@article {15484,
	title = {Shared neural transcriptomic patterns underlie the repeated evolution of mutualistic cleaning behavior in Labridae wrasses.},
	journal = {EcoEvoRxiv},
	year = {Submitted},
	url = {https://ecoevorxiv.org/4p638/},
	author = {Young, R.L. and Weitekamp, C and Triki, Z and Su, Y and Bshary, R and Hofmann, H.A.}
}
@article {14985,
	title = {Sex differences in parental response to offspring begging are associated with pair bond strength across birds},
	journal = {bioRxiv },
	year = {Submitted},
	url = {https://doi.org/10.1101/2021.10.14.464423},
	author = {Caro, SM and Wu, K and Hofmann, H. A.}
}
@article {14984,
	title = {Morpholino-mediated knockdown of the brain mineralocorticoid receptor affects glucocorticoid signaling and neuroplasticity in wild ocellated wrasse (Symphodus ocellatus)},
	journal = {bioRxiv},
	year = {Submitted},
	url = {https://doi.org/10.1101/2021.11.17.468986},
	author = {Nugent, BM and Stiver, KA and Han, J and Kindsvater, HK and Marsh-Rollo, SE and Hofmann, H. A. and Alonzo, SH}
}
@article {14833,
	title = {A tagging method for very small fish},
	journal = {bioRxiv },
	volume = {437772},
	year = {Submitted},
	month = {2018},
	url = {https://doi.org/10.1101/437772},
	author = {Solomon-Lane, TK and Hofmann, H. A.}
}
@article {13371,
	title = {Transcriptome analysis of hippocampal subfields identifies gene expression profiles associated with long-term active place avoidance memory.},
	journal = {bioRxiv},
	year = {Submitted},
	month = {2020},
	abstract = {typical protein kinase C isoform PKC\&nbsp;ι/λ\&nbsp;for acquisition of the conditioned behavior, whereas persistent activation of the other atypical PKC, protein kinase M zeta (PKMζ) is necessary for maintaining the memory for at least a month. It nonetheless remains unclear what other molecules and their interactions maintain active place avoidance long-term memory, and the candidate molecule approach is both impractical and inadequate to identify new candidates since there are so many to survey. Here we use a complementary approach to identify candidates by transcriptional profiling of hippocampus subregions after formation of the long-term active place avoidance memory. Interestingly, 24-h after conditioning and soon after expressing memory retention, immediate early genes were upregulated in the dentate gyrus but not Ammon{\textquoteright}s horn of the memory expressing group. In addition to determining what genes are differentially regulated during memory maintenance, we performed an integrative, unbiased survey of the genes with expression levels that covary with behavioral measures of active place avoidance memory persistence. Gene Ontology analysis of the most differentially expressed genes shows that active place avoidance memory is associated with activation of transcription and synaptic differentiation in dentate gyrus but not CA3 or CA1, whereas hypothesis-driven candidate molecule analyses identified insignificant changes in the expression of many LTP-associated molecules in the various hippocampal subfields, nor did they covary with active place avoidance memory expression, ruling out strong transcriptional regulation but not translational regulation, which was not investigated. These findings and the data set establish an unbiased resource to screen for molecules and evaluate hypotheses for the molecular components of a hippocampus-dependent, long-term active place avoidance memory.},
	url = {https://doi.org/10.1101/2020.02.05.935759},
	author = {Harris, R.M. and Kao, HY and Alarc{\'o}n, JM and Fenton, AA and Hofmann, H.A.}
}
@article {15486,
	title = {Vasopressin mediates nonapeptide and glucocorticoid signaling and social dynamics in juvenile dominance hierarchies of a highly social cichlid fish.},
	journal = {Hormones \& Behavior},
	volume = {145:105238},
	year = {2022},
	url = {https://doi.org/10.1016/j.yhbeh.2022.105238},
	author = {Solomon-Lane, TK and Butler, RM and Hofmann, H. A.}
}
@article {15485,
	title = {Social status mediates behavioral, endocrine, and neural responses to an intruder challenge in a social cichlid, Astatotilapia burtoni.},
	journal = {Hormones \& Behavior},
	volume = {145:105241},
	year = {2022},
	url = {https://doi.org/10.1016/j.yhbeh.2022.105241},
	author = {Friesen, CN and Maclaine, KD and Hofmann, H. A.}
}
@article {14834,
	title = {Social ascent changes cognition, behavior, and physiology in a highly social cichlid fish.},
	journal = {Philosophical Transactions B},
	volume = {377:20200448},
	year = {2022},
	url = {https://royalsocietypublishing.org/doi/abs/10.1098/rstb.2020.0448},
	author = {Wallace, KJ and Choudhary, KD and Kutty, LA and Le, DH and Lee, MT and Wu, K and Hofmann, H.A.}
}
@article {13904,
	title = {Differential neural activity patterns mediate learning across contexts in a social cichlid fish.},
	journal = {Proc R. Soc},
	year = {2022},
	month = {2},
	url = {https://royalsocietypublishing.org/doi/10.1098/rspb.2022.0135},
	author = {Rodriguez-Santiago, M and Jordan, AL and Hofmann, H.A.}
}
@article {14836,
	title = {A 2b-RAD parentage analysis pipeline for complex and mixed DNA samples.},
	journal = {Forensics Science International. Genetics},
	volume = {55:102590},
	year = {2021},
	url = {https://doi.org/10.1016/j.fsigen.2021.102590},
	author = {Miller-Crews, I and Matz, MV and Hofmann, H.A.}
}
@article {14835,
	title = {Human population density and reproductive health: a changing world needs endocrinology},
	journal = {Endocrinology},
	volume = {162:1{\textendash}3},
	year = {2021},
	url = {https://doi.org/10.1210/endocr/bqab198},
	author = {Weitekamp, C.A. and Hofmann, H.A.}
}
@article {14004,
	title = {Decision-making in a social world: integrating cognitive ecology and social neuroscience},
	journal = {Current Opinion in Neurobiology},
	volume = {68},
	year = {2021},
	pages = {152-158},
	abstract = {Understanding animal decision-making involves simultaneously dissecting and reconstructing processes across levels of biological organization, such as behavior, physiology, and brain function, as well as considering the environment in which decisions are made. Over the past few decades, foundational breakthroughs\&nbsp;originating from a variety of model systems and disciplines\&nbsp;have painted an increasingly comprehensive picture of how individuals sense information, process it, and subsequently modify behavior or states. Still, our understanding of decision-making in social contexts is far from complete and requires integrating novel approaches and perspectives. The fields of social neuroscience and cognitive ecology have approached social decision-making from orthogonal perspectives. The integration of these perspectives (and fields) is critical in developing comprehensive and testable theories of the brain.},
	url = {https://doi.org/10.1016/j.conb.2021.03.009},
	author = {Wallace, KJ and Hofmann, H.A.}
}
@article {14003,
	title = {Effects of air pollution exposure on social behavior: a synthesis and call for research.},
	journal = {Environmental Health},
	volume = {20:72},
	year = {2021},
	abstract = {
	Background: There is a growing literature from both epidemiologic and experimental animal studies suggesting that exposure to air pollution can lead to neurodevelopmental and neuropsychiatric disorders. Here, we suggest that efects of air pollutant exposure on the brain may be even broader, with the potential to afect social decision-making in general. Methods: We discuss how the neurobiological substrates of social behavior are vulnerable to air pollution, then briefy present studies that examine the efects of air pollutant exposure on social behavior-related outcomes.



	Results: Few experimental studies have investigated the efects of air pollution on social behavior and those that have focus on standard laboratory tests in rodent model systems. Nonetheless, there is sufcient evidence to support a critical need for more research. Conclusion: For future research, we suggest a comparative approach that utilizes diverse model systems to probe the efects of air pollution on a wider range of social behaviors, brain regions, and neurochemical pathways. Keywords: Air pollution, Social behavior, Particulate matter, Ozone, Social decision-making network, Dopamine, Sex steroids, Inhalation, Hazardous air pollutants

},
	url = {https://doi.org/10.1186/s12940-021-00761-8},
	author = {Weitekamp, C.A. and Hofmann, H.A.}
}
@article {13905,
	title = {Social network dynamics predict hormone levels and behavior in a highly social cichlid fish},
	journal = {Hormones \& Behavior},
	volume = {132:104994.},
	year = {2021},
	url = {https://doi.org/10.1016/j.yhbeh.2021.104994},
	author = {Maguire, S.M. and DeAngelis, R and Dijkstra, P D and Jordan, A and Hofmann, H.A.}
}
@article {13374,
	title = {Transcription factor motifs associated with anterior insula gene-expression underlying mood disorder phenotypes.},
	journal = {Molecular Neurobiology},
	year = {2021},
	abstract = {
	Background\&nbsp;Mood disorders represent a major cause of morbidity and mortality worldwide but the brain-related molecular pathophysiology in mood disorders remains largely undefined.



	Methods\&nbsp;Because the anterior insula is reduced in volume in patients with mood disorders, RNA was extracted from postmortem mood disorder samples and compared with unaffected control samples for RNA-sequencing identification of differentially expressed genes (DEGs) in\&nbsp;a) bipolar disorder (BD; n=37) versus (vs.) controls (n=33), and\&nbsp;b) major depressive disorder (MDD n=30) vs controls, and\&nbsp;c) low vs. high Axis-I comorbidity (a measure of cumulative psychiatric disease burden). Given the regulatory role of transcription factors (TFs) in gene expression via specific-DNA-binding domains (motifs), we used JASPAR TF binding database to identify TF-motifs.



	Results\&nbsp;We found that DEGs in BD vs. controls, MDD vs. controls, and high vs. low Axis-I comorbidity were associated with TF-motifs that are known to regulate expression of toll-like receptor genes, cellular homeostatic-control genes, and genes involved in embryonic, cellular/organ and brain development.



	Discussion\&nbsp;Robust imaging-guided transcriptomics\&nbsp;(i.e., using meta-analytic imaging results to guide independent post-mortem dissection for RNA-sequencing) was applied by targeting the gray matter volume reduction in the anterior insula in mood disorders, to guide independent postmortem identification of TF motifs regulating DEG. TF motifs were identified for immune, cellular, embryonic and neurodevelopmental processes.



	Conclusion\&nbsp;Our findings of TF-motifs that regulate the expression of immune, cellular homeostatic-control, and developmental genes provides novel information about the hierarchical relationship between gene regulatory networks, the TFs that control them, and proximate underlying neuroanatomical phenotypes in mood disorders.

},
	url = {https://link.springer.com/article/10.1007/s12035-020-02195-8},
	author = {Arasappan, D and Eickhoff, SB and Nemeroff, CB and Hofmann, H.A. and Jabbi, M}
}
@article {13373,
	title = {Prenatal exposure to EDCs dis-integrates and reconstitutes neuromolecular-behavioral relationships in adult rats.},
	journal = {Journal of the Endocrine Society},
	year = {2021},
	abstract = {Exposure to endocrine-disrupting chemicals (EDCs) is ubiquitous in all species, including humans. Previous studies have shown behavioral deficits caused by EDCs that have implications for social competence and sexual selection. The neuromolecular mechanisms for these behavioral changes induced by EDCs have not been thoroughly explored. Here, we tested the hypothesis that EDCs administered to rats during a critical period of embryonic brain development would lead to disruption of normal social preference behavior, and that this involves a network of underlying gene pathways in brain regions that regulate these behaviors. Rats were exposed prenatally to human-relevant concentrations of EDCs [polychlorinated biphenyls (PCB), an industrial chemical mixture; vinclozolin (VIN), a fungicide], or vehicle. In adulthood, a sociosexual preference test (choice between hormone-primed and hormone-depleted opposite-sex rats) was administered. We profiled gene expression of in three brain regions involved in these behaviors [preoptic area (POA), medial amygdala (MeA), ventromedial nucleus (VMN)]. Prenatal PCBs impaired sociosexual preference in both sexes, and VIN disrupted this behavior in males. Each brain region (POA, MeA, VMN) had unique sets of genes altered in a sex- and EDC-specific manner. Sexually dimorphic gene expression disruption was particularly prominent for gene modules pertaining to sex steroid hormones and nonapeptides in the MeA. EDC exposure also changed the relationships between gene expression and behavior in the mate preference test, a pattern we refer to as dis-integration and reconstitution. These findings underscore the profound effects that developmental exposure to EDCs can have on adult social behavior, highlight sex-specific and individual variation in responses, and provide a foundation for further work on the disruption of mate preference behavior after prenatal exposure to EDCs.},
	url = {https://doi.org/10.1210/jendso/bvab021},
	author = {Hernandez Scudder, ME and Young, R.L. and Thompson, LM and Kore, P and Crews, D and Hofmann, H.A. and Gore, AC}
}
@article {13372,
	title = {Equal performance but distinct behaviors: sex differences in a novel object recognition task and spatial maze in a highly social cichlid fish},
	journal = {Animal Cognition },
	year = {2021},
	abstract = {
	Sex differences in behavior and cognition can be driven by differential selection pressures from the environment and in the underlying neuromolecular mechanisms of decision-making. The highly social cichlid fish\&nbsp;Astatotilapia burtoni\&nbsp;exhibits dynamic and complex social hierarchies, yet explicit cognitive testing (outside of social contexts) and investigations of sex differences in cognition have yet to be fully explored. Here we assessed male and female\&nbsp;A. burtoni\&nbsp;in two cognitive tasks: a novel object recognition task and a spatial task. We hypothesized that males outperform females in a spatial learning task and exhibit more neophilic/exploratory behavior in across both tasks. In the present study we find that both sexes prefer the familiar object in a novel object recognition task, but the time at which they exhibit this preference differs between the sexes. Females more frequently learned the spatial task, exhibiting longer decision latencies and quicker error correction, suggesting a potential speed-accuracy tradeoff.



	Furthermore, the sexes differ in space use in both tasks and in a principal component analysis of the spatial task. A model selection analysis finds that preference, approach, and interaction duration in the novel object recognition task that reach a threshold of importance averaged across all models. This work highlights the need to explicitly test for sex differences in cognition to better understand how individuals navigate dynamic social environments.

},
	url = {https://doi.org/10.1007/s10071-021-01498-0},
	author = {Wallace, KJ and Hofmann, H.A.}
}
@article {13370,
	title = {Comparative transcriptomics reveal distinct patterns of gene expression conservation through vertebrate embryogenesis.},
	journal = {Genome Biology and Evolution},
	year = {2021},
	abstract = {Despite life{\textquoteright}s diversity, studies of variation across animals often remind us of our shared evolutionary past. Abundant genome sequencing over the last ~25 years reveals remarkable conservation of genes and recent analyses of gene regulatory networks illustrate that not only genes but entire pathways are conserved, reused, and elaborated in the evolution of diversity. Predating these discoveries, 19th-century embryologists observed that though morphology at birth varies tremendously, certain stages of embryogenesis appear remarkably similar across vertebrates. Specifically, while early and late stages are variable across species, anatomy of mid-stages embryos (the {\textquoteleft}phylotypic{\textquoteright} stage) is conserved. This model of vertebrate development and diversification has found mixed support in recent analyses comparing gene expression across species possibly owing to differences across studies in species, embryonic stages, and gene sets compared. Here we perform a comparative analysis using 186 microarray and RNA-seq expression data sets covering embryogenesis in six vertebrate species spanning ~420 million years of evolution. We use an unbiased clustering approach to group stages of embryogenesis by transcriptomic similarity and ask whether gene expression similarity of clustered embryonic stages deviates from the null hypothesis of no relationship between timing and diversification. We use a phylogenetic comparative approach to characterize expression conservation pattern (i.e., early conservation, hourglass, inverse hourglass, late conservation, or no relationship) of each gene at each evolutionary node. Across vertebrates, we find an enrichment of genes exhibiting early conservation, hourglass, late conservation patterns and a large depletion of gene exhibiting no distinguishable pattern of conservation in both microarray and RNA-seq data sets. Enrichment of genes showing patterned conservation through embryogenesis indicates diversification of embryogenesis may be temporally constrained. However, the circumstances (e.g., gene groups, evolutionary nodes, species) under which each pattern emerges remain unknown and require both broad evolutionary sampling and systematic examination of embryogenesis across species.},
	url = {https://doi.org/10.1093/gbe/evab160},
	author = {Chan, ME and Bhamidipati, PS and Goldsby, HJ and Hintze, A and Hofmann, H.A. and Young, R.L.}
}
@article {13351,
	title = {Courting danger: Socially dominant cichlid fish adjust their startle-escape behavior to compensate for increased visual conspicuousness to avian predators.},
	journal = {Hydrobiologia},
	year = {2021},
	url = {https://doi.org/10.1007/s10750-020-04475-9},
	author = {Whitaker, K W and Alvarez, M and Preuss, T and Cummings, ME and Hofmann, H.A.}
}
@article {13350,
	title = {Neural and molecular mechanisms underlying female mate choice decisions in vertebrates},
	journal = {Journal of Experimental Biology},
	volume = {223},
	year = {2020},
	pages = {jeb207324},
	abstract = {Female mate choice is a dynamic process that allows individuals to selectively mate with those of the opposite sex that display a preferred set of traits. Because in many species males compete with each other for fertilization opportunities, female mate choice can be a powerful agent of sexual selection, often resulting in highly conspicuous traits in males. Although the evolutionary causes and consequences of the ornamentation and behaviors displayed by males to attract mates have been well studied, embarrassingly little is known about the proximate neural mechanisms through which female choice occurs. In vertebrates, female mate choice is inherently a social behavior, and although much remains to be discovered about this process, recent evidence suggests the neural substrates and circuits underlying other fundamental social behaviors (such as pair bonding, aggression and parental care) are likely similarly recruited during mate choice. Notably, female mate choice is not static, as social and ecological environments can shape the brain and, consequently, behavior in specific ways. In this Review, we discuss how social and/or ecological influences mediate female choice and how this occurs within the brain. We then discuss our current understanding of the neural substrates underlying female mate choice, with a specific focus on those that also play a role in regulating other social behaviors. Finally, we propose several promising avenues for future research by highlighting novel model systems and new methodological approaches, which together will transform our understanding of the causes and consequences of female mate choice.},
	url = {https://doi.org/10.1242/jeb.207324},
	author = {DeAngelis, R and Hofmann, H.A.}
}
@article {13036,
	title = {Transcriptome analysis of hippocampal subfields identifies gene expression profiles associated with long-term active place avoidance memory.},
	journal = {Hippocampus},
	year = {2020},
	abstract = {The hippocampus plays a critical role in storing and retrieving spatial information. By targeting the dorsal hippocampus and manipulating specific {\textquotedblleft}candidate{\textquotedblright} molecules using pharmacological and genetic manipulations, we have previously discovered that long-term active place avoidance memory requires transient activation of particular molecules in dorsal hippocampus. These molecules include amongst others, the persistent kinases Ca-calmodulin kinase II (CaMKII) and the atypical protein kinase C isoform PKC\&nbsp;ι/λ\&nbsp;for acquisition of the conditioned behavior, whereas persistent activation of the other atypical PKC, protein kinase M zeta (PKMζ) is necessary for maintaining the memory for at least a month. It nonetheless remains unclear what other molecules and their interactions maintain active place avoidance long-term memory, and the candidate molecule approach is both impractical and inadequate to identify new candidates since there are so many to survey. Here we use a complementary approach to identify candidates by transcriptional profiling of hippocampus subregions after formation of the long-term active place avoidance memory. Interestingly, 24-h after conditioning and soon after expressing memory retention, immediate early genes were upregulated in the dentate gyrus but not Ammon{\textquoteright}s horn of the memory expressing group. In addition to determining what genes are differentially regulated during memory maintenance, we performed an integrative, unbiased survey of the genes with expression levels that covary with behavioral measures of active place avoidance memory persistence. Gene Ontology analysis of the most differentially expressed genes shows that active place avoidance memory is associated with activation of transcription and synaptic differentiation in dentate gyrus but not CA3 or CA1, whereas hypothesis-driven candidate molecule analyses identified insignificant changes in the expression of many LTP-associated molecules in the various hippocampal subfields, nor did they covary with active place avoidance memory expression, ruling out strong transcriptional regulation but not translational regulation, which was not investigated. These findings and the data set establish an unbiased resource to screen for molecules and evaluate hypotheses for the molecular components of a hippocampus-dependent, long-term active place avoidance memory.},
	url = {https://www.biorxiv.org/content/10.1101/2020.02.05.935759v1},
	author = {Harris, R. M. and Kao, H-Y and Alarc{\'o}n, JM and Fenton, AA and Hofmann, H. A.}
}
@article {13035,
	title = {Neuro-transcriptomic signatures for mood disorder morbidity and suicide mortality},
	journal = {Journal of Psychiatric Research},
	volume = {127},
	year = {2020},
	pages = {62-74},
	abstract = {
	Suicidal behaviors are strongly linked with mood disorders, but the specific neurobiological and functional gene-expression correlates for this linkage remain elusive. We performed neuroimaging-guided RNA-sequencing in two studies to test the hypothesis that imaging-localized gray matter volume (GMV) loss in mood disorders, harbors gene-expression changes associated with disease morbidity and related suicide mortality in an independent postmortem cohort. To do so, first, we conducted study 1 using an anatomical likelihood estimation (ALE) MRI meta-analysis including a total of 47 voxel-based morphometry (VBM) publications (i.e. 26 control versus (vs) major depressive disorder (MDD) studies, and 21 control vs bipolar disorder (BD) studies) in 2387 (living) participants. Study 1 meta-analysis identified a selective anterior insula cortex (AIC) GMV loss in mood disorders. We then used this results to guide study 2\&nbsp;postmortem\&nbsp;tissue dissection and RNA-Sequencing of 100 independent donor brain samples with a life-time history of MDD (N\&nbsp;=\&nbsp;30), BD (N\&nbsp;=\&nbsp;37) and control (N\&nbsp;=\&nbsp;33). In study 2, exploratory factor-analysis identified a higher-order factor representing number of Axis-1 diagnoses (e.g. substance use disorders/psychosis/anxiety, etc.), referred to here as\&nbsp;morbidity\&nbsp;and suicide-completion referred to as\&nbsp;mortality. Comparisons of case-vs-control, and factor-analysis defined higher-order-factor contrast variables revealed that the imaging-identified AIC GMV loss sub-region harbors differential gene-expression changes in high morbidity-\&amp;-mortality\&nbsp;versus\&nbsp;low morbidity-\&amp;-mortality cohorts in immune, inflammasome, and neurodevelopmental pathways. Weighted gene co-expression network analysis further identified co-activated gene modules for psychiatric morbidity and mortality outcomes. These results provide evidence that AIC anatomical signature for mood disorders are possible correlates for gene-expression abnormalities in mood morbidity and suicide mortality.




},
	url = {https://www.sciencedirect.com/science/article/abs/pii/S0022395619308337?via\%3Dihub},
	author = {Jabbi, M and Arasappan, D and Eickhoff, SB and Strakowski, M and Nemeroff, CB and Hofmann, H. A.}
}
@article {13034,
	title = {Brain transcriptomics of agonistic behaviour in the weakly electric fish Gymnotus omarorum, a wild teleost model of non-breeding aggression},
	journal = {Scientific Reports},
	volume = {10},
	number = {9496},
	year = {2020},
	abstract = {
	
		
			Article
		
		
			Open Access
		
		
			Published:\&nbsp;11 June 2020
		
	

	
		Brain transcriptomics of agonistic behaviour in the weakly electric fish\&nbsp;Gymnotus omarorum, a wild teleost model of non-breeding aggression
	

	
		
			Guillermo Eastman,\&nbsp;
		
		
			Guillermo Vali{\~n}o,\&nbsp;
		
		
			Santiago Rad{\'\i}o,\&nbsp;
		
		
			Rebecca L. Young,\&nbsp;
		
		
			Laura Quintana,\&nbsp;
		
		
			Harold H. Zakon,\&nbsp;
		
		
			Hans A. Hofmann,\&nbsp;
		
		
			Jos{\'e} Sotelo-Silveira\&nbsp;\&amp;\&nbsp;
		
		
			Ana Silva\&nbsp;
		
	

	
		Scientific Reports\&nbsp;volume\&nbsp;10, Article\&nbsp;number:\&nbsp;9496\&nbsp;(2020)\&nbsp;Cite this article
	

	
		
			
				543\&nbsp;Accesses
			
		
		
			
				34\&nbsp;Altmetric
			
		
		
			
				Metricsdetails
			
		
	



	
		Abstract
	

	
		Differences in social status are often mediated by agonistic encounters between competitors. Robust literature has examined social status-dependent brain gene expression profiles across vertebrates, yet social status and reproductive state are often confounded. It has therefore been challenging to identify the neuromolecular mechanisms underlying social status independent of reproductive state. Weakly electric fish,\&nbsp;Gymnotus omarorum, display territorial aggression and social dominance independent of reproductive state. We use wild-derived\&nbsp;G. omarorum\&nbsp;males to conduct a transcriptomic analysis of non-breeding social dominance relationships. After allowing paired rivals to establish a dominance hierarchy, we profiled the transcriptomes of brain sections containing the preoptic area (region involved in regulating aggressive behaviour) in dominant and subordinate individuals. We identified 16 differentially expressed genes (FDR \&lt; 0.05) and numerous genes that co-varied with behavioural traits. We also compared our results with previous reports of differential gene expression in other teleost species. Overall, our study establishes\&nbsp;G. omarorum\&nbsp;as a powerful model system for understanding the neuromolecular bases of social status independent of reproductive state.
	

},
	url = {https://www.nature.com/articles/s41598-020-66494-9},
	author = {Eastman, G and Vali{\~n}o, G and Rad{\'\i}o, S and Young, R.L. and Quintana, L and Zakon, HH and Hofmann, H. A. and Sotelo-Silveira, J and Silva, A}
}
@article {13033,
	title = {Behavior-related gene regulatory networks: A new level of organization in the brain.},
	journal = {Proceedings of the National Academy of Sciences USA},
	year = {2020},
	abstract = {Neuronal networks are the standard heuristic model today for describing brain activity associated with animal behavior. Recent studies have revealed an extensive role for a completely distinct layer of networked activities in the brain{\textemdash}the gene regulatory network (GRN){\textemdash}that orchestrates expression levels of hundreds to thousands of genes in a behavior-related manner. We examine emerging insights into the relationships between these two types of networks and discuss their interplay in spatial as well as temporal dimensions, across multiple scales of organization. We discuss properties expected of behavior-related GRNs by drawing inspiration from the rich literature on GRNs related to animal development, comparing and contrasting these two broad classes of GRNs as they relate to their respective phenotypic manifestations. Developmental GRNs also represent a third layer of network biology, playing out over a third timescale, which is believed to play a crucial mediatory role between neuronal networks and behavioral GRNs. We end with a special emphasis on social behavior, discuss whether unique GRN organization and\&nbsp;cis-regulatory architecture underlies this special class of behavior, and review literature that suggests an affirmative answer.},
	url = {https://www.pnas.org/content/early/2020/07/10/1921625117},
	author = {S Sinha and Jones, BM and Traniello, IM and Bukhari, SA and Halfon, MS and Hofmann, H. A. and Huang, S and Katz, PS and Keagy, J and Lynch, VJ and Sokolowski, MB and Stubbs, LJ and Tabe-Bordbar, S and Wolfner, MF and Robinson, GE}
}
@article {13032,
	title = {Behavioral traits that define social dominance are the same that reduce social influence in a consensus task.},
	journal = {Proceedings of the National Academy of Sciences USA},
	year = {2020},
	abstract = {Dominant individuals are often most influential in their social groups, affecting movement, opinion, and performance across species and contexts. Yet, behavioral traits like aggression, intimidation, and coercion, which are associated with and in many cases define dominance, can be socially aversive. The traits that make dominant individuals influential in one context may therefore reduce their influence in other contexts. Here, we examine this association between dominance and influence using the cichlid fish\&nbsp;Astatotilapia burtoni, comparing the influence of dominant and subordinate males during normal social interactions and in a more complex group consensus association task. We find that phenotypically dominant males are aggressive, socially central, and that these males have a strong influence over normal group movement, whereas subordinate males are passive, socially peripheral, and have little influence over normal movement. However, subordinate males have the greatest influence in generating group consensus during the association task. Dominant males are spatially distant and have lower signal-to-noise ratios of informative behavior in the association task, potentially interfering with their ability to generate group consensus. In contrast, subordinate males are physically close to other group members, have a high signal-to-noise ratio of informative behavior, and equivalent visual connectedness to their group as dominant males. The behavioral traits that define effective social influence are thus highly context specific and can be dissociated with social dominance. Thus, processes of hierarchical ascension in which the most aggressive, competitive, or coercive individuals rise to positions of dominance may be counterproductive in contexts where group performance is prioritized.},
	url = {https://www.pnas.org/content/early/2020/07/15/2000158117},
	author = {Rodriguez-Santiago, M and N{\"u}hrenberg, P and Derry, J and Deussen, O and Francisco, FA and Garrison, LK and Garza, SF and Hofmann, H.A. and Jordan, A}
}
@article {11433,
	title = {Estradiol treatment improves biological rhythms in a preclinical rat model of menopause},
	journal = {Neurobiology of Aging},
	year = {2019},
	abstract = {The perimenopausal transition at middle age is often associated with hot flashes and sleep disruptions, metabolic changes, and other symptoms. Whereas the mechanisms for these processes are incompletely understood, both aging and a loss of ovarian estrogens play contributing roles. Furthermore, the timing of when estradiol treatment should commence, and for how long, are key clinical questions in the management of symptoms. Using a rat model of surgical menopause, we determined the effects of regimens of estradiol treatment with differing time at onset and duration of treatment on diurnal rhythms of activity and core temperature, and on food intake and body weight. Reproductively mature (MAT, \~{}4 mo.) or aging (AG, \~{}11 mo.) female rats were ovariectomized, implanted intraperitoneally with a telemetry device, and given either a vehicle (V) or estradiol (E) subcutaneous capsule implantation. Rats were remotely recorded for 10 days per month for 3 (MAT) or 6 (AG) months. To ascertain whether delayed onset of treatment affected rhythms, a subset of AG-V rats had their capsules switched to E at the end of 3 months. Another set of AG-E rats had their capsules removed at 3 months to determine whether beneficial effects of E would persist. Overall, activity and temperature mesor, robustness, and amplitude declined with aging. Compared to V treatment, E treated rats showed: 1) better maintenance of body weight and food intake; 2) higher, more consolidated activity and temperature rhythms; and 3) higher activity and temperature robustness and amplitude. In the AG arm of the study, switching treatment from V to E or E to V quickly reversed these patterns. Thus, the presence of E was the dominant factor in determining stability and amplitude of locomotor activity and temperature rhythms. As a whole the results show benefits of E treatment, even with a delay, on biological rhythms and physiological functions.},
	author = {Yin, W and Borniger, JC and X Wang and Maguire, S.M. and Munselle, ML and Bezner, KS and Tesfamariam, HM and Liang, J and Garcia, AN and Hofmann, H.A. and Nelson, RJ and Gore, AC}
}
@article {11320,
	title = {Coevolution of genome architecture and social behavior},
	journal = {Trends in Ecology and Evolution},
	volume = {34},
	number = {9},
	year = {2019},
	pages = {844-855},
	abstract = {Although social behavior can have a strong genetic component, it can also result in selection on genome structure and function, thereby influencing the evolution of the genome itself. Here we explore the bidirectional links between social behavior and genome architecture by considering variation in social and/or mating behavior among populations (social polymorphisms) and across closely related species. We propose that social behavior can influence genome architecture via associated demographic changes due to social living. We establish guidelines to exploit emerging whole-genome sequences using analytical approaches that examine genome structure and function at different levels (regulatory vs structural variation) from the perspective of both molecular biology and population genetics in an ecological context.},
	url = {https://www.sciencedirect.com/science/article/pii/S0169534719301338?via\%3Dihub},
	author = {Rubenstein, DR and Agren, JA and Carbone, L and Hoekstra, HE and Kapheim, KM and Keller, L and Moreau, CS and Toth, AL and Yeaman, S and Hofmann, H. A.}
}
@article {11319,
	title = {Multimodal stimuli regulate reproductive behavior and physiology in male t{\'u}ngara frogs},
	journal = {Hormones and Behavior},
	year = {2019},
	abstract = {Unlike in terrestrial animals, the boundary between internal (e.g., hormones) and external (e.g., social) stimulation can be blurred for aquatic and amphibious species. When chemicals such as hormones and glandular secretions leach into the water, they can further interact with other signaling systems, creating multimodal stimuli. It is unclear, however, whether water-borne chemical secretions from courting male frogs affect the physiology and behavior of their rivals. In order to address this question we first established non-invasive, continuous sampling methods for simultaneously measuring both hormones and behavior in amphibious species. Then, we examined whether interactions between water-borne chemical secretions and conspecific calls affect reproductive behavior and physiology (testosterone and corticosterone) of courting male t{\'u}ngara frogs. Our results demonstrate that conspecific acoustic stimulation alone increases locomotor activity, decreases latency to call, and increases calling behavior but does not alter the amount of hormones excreted. In response to water containing chemical secretions from rivals, but in the absence of calls from other males, males excrete more testosterone. Interestingly, the combined acoustic and chemical stimulus causes a multiplicative increase in both calling behavior and hormonal excretion. Taken together, our results suggest that a multimodal chemical-acoustic stimulus physiologically primes males for aggressive behavior.},
	url = {https://www.sciencedirect.com/science/article/pii/S0018506X1930128X?via\%3Dihub},
	author = {Still, MB and Lea, AM and Hofmann, H. A. and Ryan, M. J.}
}
@article {11318,
	title = {Molecular profiling of single neurons of known identity in two ganglia from the crab Cancer borealis},
	journal = {Proceedings of the National Academy of Sciences USA},
	year = {2019},
	abstract = {Understanding circuit organization depends on identification of cell types. Recent advances in transcriptional profiling methods have enabled classification of cell types by their gene expression. While exceptionally powerful and high throughput, the ground-truth validation of these methods is difficult: if cell type is unknown, how does one assess whether a given analysis accurately captures neuronal identity? To shed light on the capabilities and limitations of solely using transcriptional profiling for cell type classification, we performed two forms of transcriptional profiling {\textendash} RNA-seq and quantitative RT-PCR, in single, unambiguously identified neurons from two small crustacean networks: the stomatogastric and cardiac ganglia. We then combined our knowledge of cell type with unbiased clustering analyses and supervised machine learning to determine how accurately functionally-defined neuron types can be classified by expression profile alone. Our results demonstrate that expression profile is able to capture neuronal identity most accurately when combined with multimodal information that allows for post-hoc grouping so analysis can proceed from a supervised perspective. Solely unsupervised clustering can lead to misidentification and an inability to distinguish between two or more cell types. Therefore, our study supports the general utility of cell identification by transcriptional profiling, but adds a caution: it is difficult or impossible to know under what conditions transcriptional profiling alone is capable of assigning cell identity. Only by combining multiple modalities of information such as physiology, morphology or innervation target can neuronal identity be unambiguously determined.},
	url = {https://www.biorxiv.org/content/10.1101/690388v1},
	author = {Northcutt, AJ and Kick, DR and Otopalik, A. G. and Goetz, BM and Harris, R.M. and Santin, JM and Hofmann, H.A. and Marder, E and Schulz, DJ}
}
@article {11108,
	title = {Hippocampal transcriptomic responses to enzyme-mediated cellular dissociation},
	journal = {Hippocampus},
	year = {2019},
	pages = {1-7},
	abstract = {
	Single-neuron gene expression studies may be especially important for understanding nervous system structure and function because of the neuron-specific functionality and plasticity that defines functional neural circuits. Cellular dissociation is a prerequi- site technical manipulation for single-cell and single cell-population studies, but the extent to which the cellular dissociation process affects neural gene expression has not been determined. This information is necessary for interpreting the results of experi- mental manipulations that affect neural function such as learning and memory. The goal of this research was to determine the impact of cellular dissociation on brain transcriptomes. We compared gene expression of microdissected samples from the dentate gyrus (DG), CA3, and CA1 subfields of the mouse hippocampus either prepared by a standard tissue homogenization protocol or subjected to enzymatic digestion used to dissociate cells within tissues. We report that compared to homoge- nization, enzymatic dissociation alters about 350 genes or 2\% of the hippocampal transcriptome. While only a few genes canonically implicated in long-term potentiation and fear memory change expression levels in response to the dissociation procedure, these data indicate that sample preparation can affect gene expression profiles, which might confound interpretation of results depending on the research question. This study is important for the investigation of any complex tissues as research effort moves from subfield level analysis to single cell analysis of gene expression.

},
	url = {https://onlinelibrary.wiley.com/doi/epdf/10.1002/hipo.23095},
	author = {Harris, Rayna M. and Kao, Hsin-Yi and Alarcon, Juan Marcos and Hofmann, Hans A. and Fenton, Andre A.}
}
@article {10369,
	title = {Molecular origins and outcomes of status and stress in primates},
	journal = {Proceedings of the National Academy of Sciences USA},
	volume = {116},
	number = {4},
	year = {2019},
	pages = {1081-1083},
	url = {www.pnas.org/cgi/doi/10.1073/pnas.1819472116},
	author = {Friesen, CN and Hofmann, H.A.}
}
@article {10366,
	title = {Early-life social environment alters juvenile behavior and neuroendocrine function in a highly social cichlid fish},
	journal = {Hormones and Behavior},
	volume = {115},
	year = {2019},
	abstract = {Early-life experiences can shape adult behavior, with consequences for fitness and health, yet fundamental questions remain unanswered about how early-life social experiences are translated into variation in brain and behavior. The African cichlid fish\&nbsp;Astatotilapia burtoni, a model system in social neuroscience, is well known for its highly plastic social phenotypes in adulthood. Here, we rear juveniles in either social groups or pairs to investigate the effects of early-life social environments on behavior and neuroendocrine gene expression. We find that both juvenile behavior and neuroendocrine function are sensitive to early-life effects. Behavior robustly co-varies across multiple contexts (open field, social cue investigation, and dominance behavior assays) to form a behavioral syndrome, with pair-reared juveniles towards the end of syndrome that is less active and socially interactive. Pair-reared juveniles also submit more readily as subordinates. In a separate cohort, we measured whole brain expression of stress and sex hormone genes. Expression of glucocorticoid receptor 1a was elevated in group-reared juveniles, supporting a highly-conserved role for the stress axis mediating early-life effects. The effect of rearing environment on androgen receptor α and estrogen receptor α expression was mediated by treatment duration (1 vs. 5 weeks). Finally, expression of corticotropin-releasing factor and glucocorticoid receptor 2 decreased significantly over time. Rearing environment also caused striking differences in gene co-expression, such that expression was tightly integrated in pair-reared juveniles but not group-reared or isolates. Together, this research demonstrates the important developmental origins of behavioral phenotypes and identifies potential behavioral and neuroendocrine mechanisms.},
	url = {https://www.sciencedirect.com/science/article/pii/S0018506X1830518X?via\%3Dihub},
	author = {Solomon-Lane, TK and Hofmann, H.A.}
}
@article {10365,
	title = {Conserved transcriptomic profiles underpin monogamy across vertebrates},
	journal = {Proc. Natl. Acad. Sci. USA},
	volume = {116},
	number = {4},
	year = {2019},
	pages = {1331-1336},
	abstract = {Social monogamy, typically characterized by the formation of a pair bond, increased territorial defense, and often biparental care, has evolved numerous times in animals. Despite the independent evolutionary origins of monogamous mating systems, several homologous brain regions and neuroendocrine pathways play conserved roles in regulating social affiliation and parental care, but little is known about the evolution of the neuromolecular mechanisms underlying monogamy. Here, we show that shared transcriptomic profiles are associated with monogamy across vertebrates and discuss the importance of our discovery for understanding the origins of behavioral diversity. We compare neural transcriptomes of reproductive males in monogamous and nonmonogamous species pairs of mice, voles, parid songbirds, frogs, and cichlid fishes. Our results provide evidence of a universal transcriptomic code underlying monogamy in vertebrates.},
	url = {https://www.pnas.org/content/early/2019/01/02/1813775116},
	author = {Young, R.L. and Ferkin, MH and Ockendon, NF and Orr, VN and Phelps, SM and Pog{\'a}ny, {\'A} and Richards-Zawacki, CL and Summers, K and Sz{\'e}kely, T and Trainor, BC and Urrutia, AO and Zachar, G and O{\textquoteright}Connell, LA and Hofmann, H.A.}
}
@article {10364,
	title = {Experimentally-induced variation in neuroendocrine processes affects male reproductive behavior, sperm characteristics, and social interactions.},
	journal = {Molecular Ecology},
	volume = {2019},
	year = {2019},
	abstract = {
	While extensive research has focused on how social interactions evolve, the fitness consequences of the neuroendocrine mechanisms underlying these interactions have rarely been documented, especially in the wild. Here, we measure how the neuroendocrine mechanisms underlying male behavior affecting mating success and sperm competition in the ocellated wrasse (Symphodus ocellatus). In this species, males exhibit three alternative reproductive types. {\textquoteleft}Nesting males{\textquoteright} provide parental care, defend territories, and form cooperative associations with unrelated {\textquoteleft}satellites{\textquoteright}, who cheat by sneaking fertilizations but help by reducing sperm competition from {\textquoteleft}sneakers{\textquoteright} who do not cooperate or provide care. To measure the fitness consequences of the mechanisms underlying these social interactions, we used {\textquotedblleft}phenotypic engineering{\textquotedblright} that involved administering an androgen receptor antagonist (flutamide) to wild, free-living fish. Nesting males treated with flutamide shifted their aggression from sneakers to satellite males and experienced decreased submissiveness by sneaker males (which correlated with decreased nesting male mating success). The preoptic area (POA), a region controlling male reproductive behaviors, exhibited dramatic down-regulation of androgen receptor (AR) and vasotocin 1a receptor (V1aR) mRNA following experimental manipulation of androgen signaling. We did not find a direct effect of the manipulation on male mating success, paternity or larval production. However, variation in neuroendocrine mechanisms generated by the experimental manipulation was significantly correlated with changes in behavior and mating success: V1aR expression was negatively correlated with satellite-directed aggression and expression of its ligand arginine vasotocin (AVT) was positively correlated with courtship and mating success, thus revealing the potential for sexual selection on these mechanisms.

},
	url = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/mec.14999},
	author = {Nugent, BM and Stiver, KA and Hofmann, H. A. and Alonzo, SH}
}
@article {9087,
	title = {SArKS: de novo discovery of gene expression regulatory motif sites and domains by suffix array kernel smoothing},
	journal = {Bioinformatics},
	volume = {btz198},
	year = {2019},
	abstract = {
	\&nbsp;Motivation: We set out to develop an algorithm that can mine differential gene expression data to identify candidate cell type-specific DNA regulatory sequences. Differential expression is usually quantified as a continuous score{\textemdash}fold-change, test-statistic, P-value{\textemdash}comparing biological classes. Unlike existing approaches, our de novo strategy, termed SArKS, applies non-parametric kernel smoothing to uncover promoter motif sites that correlate with elevated differential expression scores. SArKS detects motif k-mers by smoothing sequence scores over sequence similarity. A second round of smoothing over spatial proximity reveals multi-motif domains (MMDs). Discovered motif sites can then be merged or extended based on adjacency within MMDs. False positive rates are estimated and controlled by permutation testing. Results: We applied SArKS to published gene expression data representing distinct neocortical neuron classes in Mus musculus and interneuron developmental states in Homo sapiens. When benchmarked against several existing algorithms using a cross-validation procedure, SArKS identified larger motif sets that formed the basis for regression models with higher correlative power. Availability and implementation: https://github.com/denniscwylie/sarks. Contact: denniswylie@austin.utexas.edu or zemelmanb@mail.clm.utexas.edu Supplementary information: Supplementary data are available at Bioinformatics online.

},
	url = {https://academic.oup.com/bioinformatics/advance-article/doi/10.1093/bioinformatics/btz198/5418797},
	author = {Wylie, DC and Hofmann, H.A. and Zemelman BV}
}
@article {11434,
	title = {A tagging method for very small fish},
	journal = {bioRxiv},
	year = {2018},
	abstract = {The ability to reliably identify individuals over time and across contexts is essential in numerous areas of science. There are a variety of well-established methods for uniquely marking individuals, such as using paint or dye, visible implant elastomer tags, numbers or barcodes glued to the animal, passive integrated transponders, and more. For some species, life history stages, and/or experiments, however, these existing tagging methods are not sufficient. Here, we describe the method we developed for tagging juveniles of the African cichlid fish,\&nbsp;Astatotilapia burtoni, which are too small for the methods used to tag adults. We used fishing line threaded through the needle of an insulin syringe to tie a loop of line through the dorsal muscle of juveniles as small as 10 mm standard length. Unique color patterns on the line can be used to distinguish among individuals. The tag is compatible with normal locomotion and social behavior, discernible to the eye and on camera, durable enough to last at least months, and the juvenile can grow with the tag. For\&nbsp;A. burtoni, which is a model system in social neuroscience, the lack of an appropriate tagging method for very small juveniles likely contributes to the relative lack of early-life studies, and the same may be true for other small species. We expect this method to be useful in a variety of species and will facilitate the integration of organismal and behavioral development into more research programs.},
	author = {Solomon-Lane, TK and Hofmann, H. A.}
}
@article {10469,
	title = {Comparative neuroendocrinology: A call for more study of reptiles!},
	journal = {Hormones and Behavior},
	volume = {106},
	year = {2018},
	pages = {189-192},
	url = {https://doi.org/10.1016/j.yhbeh.2018.10.005},
	author = {Kabelik, D and Hofmann, H.A.}
}
@conference {10368,
	title = {Serendipitous Scaffolding to improve a Genetic Algorithm\&$\#$39;s Speed and Quality},
	booktitle = {Genetic and Evolutionary Computation Conference (GECCO)},
	year = {2018},
	pages = {959-966},
	address = {Kyoto (Japan)},
	abstract = {A central challenge to evolutionary computation is enabling techniques to evolve increasingly complex target end products. Frequently direct approaches that reward only the target end product itself are not successful because the path between the starting conditions and the target end product traverses through a complex fitness landscape, where the directly accessible intermediary states may be require deleterious or even simply neutral mutations. As such, a host of techniques have sprung up to support evolutionary computation techniques taking these paths. One technique is scaffolding where intermediary targets are used to provide a path from the starting state to the end state. While scaffolding can be successful within well-understood domains it also poses the challenge of identifying useful intermediaries. Within this paper we first identify some shortcomings of scaffolding approaches --- namely, that poorly selected intermediaries may in fact hurt the evolutionary computation{\textquoteright}s chance of producing the desired target end product. We then describe a light-weight approach to selecting intermediate scaffolding states that improve the efficacy of the evolutionary computation.},
	url = {https://dl.acm.org/citation.cfm?id=3205455.3205617},
	author = {Goldsby, HJ and Young, R.L. and Hofmann, H. A. and Hintze, A}
}
@article {10367,
	title = {Real or fake? Natural and artificial social stimuli elicit divergent behavioral and neural responses in the mangrove rivulus fish, Kryptolebias marmoratus.},
	journal = {Proc. R. Soc. B.},
	volume = {285},
	number = {20181610},
	year = {2018},
	abstract = {Understanding how the brain processes social information and generates adaptive behavioural responses is a major goal in neuroscience. We examined behaviour and neural activity patterns in socially relevant brain nuclei of hermaphroditic mangrove rivulus fish (Kryptolebias marmoratus) provided with different types of social stimuli: stationary model opponent, regular mirror, non-reversing mirror and live opponent. We found that: (i) individuals faced with a regular mirror were less willing to interact with, delivered fewer attacks towards and switched their orientation relative to the opponent more frequently than fish exposed to a non-reversing mirror image or live opponent; (ii) fighting with a regular mirror image caused higher expression of immediate-early genes (IEGs: egr-1 and c-Fos) in the teleost homologues of the basolateral amygdala and hippocampus, but lower IEG expression in the preoptic area, than fighting with a non-reversing mirror image or live opponent; (iii) stationary models elicited the least behavioural and IEG responses among the four stimuli; and (iv) the nonreversing mirror image and live opponent drove similar behavioural and neurobiological responses. These results suggest that the various stimuli provide different types of information related to conspecific recognition in the context of aggressive contests, which ultimately drive different neurobiological responses.},
	url = {http://dx.doi.org/10.1098/rspb.2018.1610},
	author = {Li, CY and Hofmann, H. A. and Harris, ML and Earley, RL}
}
@article {10264,
	title = {Neural activity in the social decision-making network of the brown anole during reproductive and agonistic encounters},
	journal = {Hormones and Behavior},
	volume = {106},
	year = {2018},
	pages = {178-188},
	abstract = {Animals have evolved flexible strategies that allow them to evaluate and respond to their social environment by integrating the salience of external stimuli with internal physiological cues into adaptive behavioral responses. A highly conserved social\&nbsp;decision-makingnetwork (SDMN), consisting of interconnected\&nbsp;social behavior\&nbsp;and\&nbsp;mesolimbic\&nbsp;reward networks, has been proposed to underlie such adaptive behaviors across all vertebrates, although our understanding of this system in reptiles is very limited. Here we measure neural activation across the SDMN and associated regions in the male brown anole (Anolis sagrei), within both reproductive and\&nbsp;agonistic\&nbsp;contexts, by quantifying the expression density of the\&nbsp;immediate early gene\&nbsp;product Fos. We then relate this neural activity measure to social context, behavioral expression, and activation (as measured by colocalization with Fos) of different\&nbsp;phenotypes\&nbsp;of {\textquoteleft}source{\textquoteright} node neurons that produce\&nbsp;neurotransmittersand\&nbsp;neuropeptides\&nbsp;known to modulate SDMN {\textquoteleft}target{\textquoteright} node activity. Our results demonstrate that measures of neural activation across the SDMN network are generally independent of specific behavioral output, although Fos induction in a few select nodes of the social behavior network component of the SDMN does vary with social environment and behavioral output. Under control conditions, the mesolimbic reward nodes of the SDMN actually correlate little with the social behavior nodes, but the interconnectivity of these SDMN components increases dramatically within a reproductive context. When relating behavioral output to specific source node activation profiles, we found that\&nbsp;catecholaminergic\&nbsp;activation is associated with the frequency and intensity of reproductive behavior output, as well as with aggression intensity. Finally, in terms of the effects of source node activation on SDMN activity, we found that Ile8-oxytocin (mesotocin) populations correlate positively, while Ile3-vasopressin (vasotocin),\&nbsp;catecholamine, and\&nbsp;serotonin\&nbsp;populations correlate negatively with SDMN activity. Taken together, our findings present evidence for a highly dynamic SDMN in reptiles that is responsive to salient cues in a social context-dependent manner.},
	url = {https://doi.org/10.1016/j.yhbeh.2018.06.013},
	author = {Kabelik, David and Weitekamp, Chelsea A. and Choudhury, Shelley C. and Hartline, Jacob T. and Smith, Alexandra N. and Hofmann, Hans A.}
}
@article {9088,
	title = {Gene expression signatures of mating system evolution},
	journal = {Genome},
	year = {2018},
	abstract = {
	The diversity of mating systems among animals is astounding. Importantly, similar mating systems have evolved even across distantly related taxa. However, our understanding of the mechanisms underlying these convergently evolved phenotypes is limited. Here, we examine on a genomic scale the neuromolecular basis of social organization in Ectodini cichlids from Lake Tanganyika. Using field collected males and females of four closely related species representing two independent evolutionary transitions from polygyny to monogamy, we take a comparative transcriptomic approach to test the hypothesis that these independent transitions have recruited similar gene sets. Our results demonstrate that while lineage and species exert a strong influence on neural gene expression profiles, social phenotype can also drive gene expression evolution. Specifically, 331 genes (~6\% of those assayed) were associated with monogamous mating systems independent of species or sex. Among these genes, we find a strong bias (4:1 ratio) toward genes with increased expression in monogamous individuals. A highly conserved nonapeptide system known to be involved in the regulation of social behavior across animals was not associated with mating system in our analysis. Overall, our findings suggest deep molecular homologies underlying the convergent or parallel evolution of monogamy in different lineages of Ectodini cichlids.

},
	url = {https://doi.org/10.1139/gen-2017-0075},
	author = {Renn, S C P and Machado, HE and Duftner, N and Sessa, AK and Harris, R.M. and Hofmann, H.A.}
}
@conference {9728,
	title = {Increasing the complexity of solutions produced by an evolutionary developmental system.},
	booktitle = {Genetic and Evolutionary Computation Conference (GECCO)},
	year = {2017},
	pages = {57-58},
	address = {Berlin (Germany)},
	abstract = {
	Evolutionary computation and neuroevolution seek to create systems of ever increasing sophistication, such that the digitally evolved forms reflect the variety, diversity, and complexity seen within nature in living organisms. In general, most evolutionary computation and neuroevolution techniques do so by encoding the final form without any type of development. This is in contrast to nature, where most complex organisms go through a developmental period. Here we focus on an evolving digital tissues that develop from a single cell and unfold into a complex body plan. It quickly became evident that evolving developing forms is quite challenging. We compare four different techniques that have successfully been employed within evolutionary computation to evolve complex forms and behavior: scaffolding (i.e., gradually increasing the difficulty of the task rewarded by the environment over evolutionary time), stepping stones (i.e., rewarding easier tasks within an environment that can co-opted for the performance of more complex tasks), and island models (i.e., rewarding different fitness functions within different subpopulations with migration). We show the effect of these methods on the evolution of complex forms that develop from a single cell, the rate of adaptation, and different dimensions of robustness and variation among solutions.

},
	author = {Goldsby, H.J. and Young, R.L. and Hofmann, H.A. and Hintze, A.}
}
@inbook {9089,
	title = {Neurogenomics of behavioural plasticity in socioecological contexts.},
	booktitle = {Encyclopedia of Life Sciences},
	year = {2017},
	publisher = {John Wiley \& Sons, Ltd},
	organization = {John Wiley \& Sons, Ltd},
	address = {Chichester},
	abstract = {
	Social and ecological challenges often elicit behavioural and physiological responses that are adaptive and subject to selection. The varying behavioural states and traits of animals are a direct output of the nervous system and underlying molecular substrates. Changes in gene expression in response to a variety of contexts such as mate choice, aggression and developmental experience can alter a number of cellular and neural pathways that lead to changes in behaviour. A common framework has emerged to understand the role of the transcriptome in animal behaviour. Behavioural plasticity describes both an individual{\textquoteright}s ability to modify behavioural states and correlated suites of behaviour in populations, which may constrain variance across contexts. By integrating the study of behavioural plasticity with genome scale, bioinformatics and candidate gene analyses, we are rapidly expanding our understanding of this kind of organismal flexibility, its relationship with the genome and its evolutionary implications.

},
	url = {10.1002/9780470015902.a0026839},
	author = {Baker, MR and Hofmann, H. A. and Wong, RY}
}
@article {8868,
	title = {Arginine vasotocin preprohormone is expressed in surprising regions of the teleost forebrain},
	journal = {Frontiers in Endocrinology},
	volume = {8},
	year = {2017},
	abstract = {Nonapeptides play a fundamental role in the regulation of social behavior, among numerous other functions. In particular, arginine vasopressin and its non-mammalian homolog, arginine vasotocin (AVT), have been implicated in regulating affiliative, reproductive, and aggressive behavior in many vertebrate species. Where these nonapeptides are synthesized in the brain has been studied extensively in most vertebrate lineages. While several hypothalamic and forebrain populations of vasopressinergic neurons have been described in amniotes, the consensus suggests that the expression of AVT in the brain of teleost fish is limited to the hypothalamus, specifically the preoptic area (POA) and the anterior tuberal nucleus (putative homolog of the mammalian ventromedial hypothalamus). However, as most studies in teleosts have focused on the POA, there may be an ascertainment bias. Here, we revisit the distribution of AVT preprohormone mRNA across the dorsal and ventral telencephalon of a highly social African cichlid fish. We first use in situ hybridization to map the distribution of AVT preprohormone mRNA across the telencephalon. We then use quantitative real-time polymerase chain reaction to assay AVT expression in the dorsomedial telencephalon, the putative homolog of the mammalian basolateral amygdala. We find evidence for AVT preprohormone mRNA in regions previously not associated with the expression of this nonapeptide, including the putative homologs of the mammalian extended amygdala, hippocampus, striatum, and septum. In addition, AVT preprohormone mRNA expression within the basolateral amygdala homolog differs across social contexts, suggesting a possible role in behavioral regulation. We conclude that the surprising presence of AVT preprohormone mRNA within dorsal and medial telencephalic regions warrants a closer examination of possible AVT synthesis locations in teleost fish, and that these may be more similar to what is observed in mammals and birds.},
	url = {http://journal.frontiersin.org/article/10.3389/fendo.2017.00195/full?utm_source=FRN\&utm_medium=EMAIL_IRIS\&utm_campaign=EMI_FRN_ARTICLEPUBLISHED_COAUTHORS\&utm_content=ARTICLE_TITLE},
	author = {Rodriguez-Santiago, Mariana and Nguyen, Jessica and Winton, Lin S. and Weitekamp, Chelsea A. and Hofmann, Hans A.}
}
@article {8694,
	title = {Neuromolecular Regulation of Aggression Differs by Social Role during Joint Territory Defense},
	journal = {Integrative and Comparative Biology},
	year = {2017},
	pages = {1-9},
	abstract = {In response to a territory intrusion, neighboring males of the African cichlid fish Astatotilapia burtoni engage in aggressive joint territory defense in a manner that depends on their social role. Here, we examine the possible function of several neuroendocrine and neuromodulator pathways previously implicated in the regulation of complex social behavior. We find that the neuromolecular regulation of aggression during joint territory defense is very much dependent on an individual{\textquoteright}s role in this context. In neighbors but not in residents, aggression is correlated to gene expression in the medial part of the dorsal telencephalon (area Dm), the putative homolog to the mammalian basolateral amygdala. This correlation is strikingly high for expression of the serotonin receptor 5-HT2c, suggesting the serotonin system is important in regulating context-dependent behavior. Furthermore, by examining candidate gene expression co-variance patterns in area Dm and in the lateral part of the dorsal telencephalon (area Dl), the putative homolog to the mammalian hippocampus, we identify two main patterns: gene expression is co-regulated within, but not across, brain regions, and co-regulation is synergistic rather than antagonistic. Our results highlight the critical effect of social context on both behavior and its neuromolecular basis.},
	author = {Weitekamp, C.A. and Nguyen, J. and Hofmann, H.A.}
}
@article {8695,
	title = {Social context affects behavior, preoptic area gene expression, and response to D2 receptor manipulationduring territorial defense in a cichlid fish},
	journal = {Genes, Brain and Behavior},
	volume = {16},
	year = {2017},
	pages = {601-611},
	abstract = {
	Social context often has profound effects on behavior, yet the neural and molecular mechanisms which mediate flexible behavioral responses to different social environments are not well understood. We used the African cichlid fish, Astatotilapia burtoni, to examine aggressive defense behavior across three social contexts representing different motivational states: a reproductive opportunity, a familiar male and a neutral context.To elucidate how differences in behavior across con-texts may be mediated by neural gene expression, we examined gene expression in the preoptic area, a brain region known to control male aggressive and sexual behavior. We show that social context has broad effects on preoptic gene expression. Specifically, we found that the expression of genes encoding nonapeptides and sex steroid receptors are upregulated in the familiar male context. Furthermore, circulating levels of testosterone and cortisol varied markedly depending on social context. We also manipulated the D2 receptor (D2R) ineach social context, given that it has been implicated in mediating context-dependent behavior. We found that a D2R agonist reduced intruder-directed aggression in the reproductive opportunity and familiar male contexts, while a D2R antagonist inhibited intruder-directed aggression in the reproductive opportunity context and increased aggression in the neutral context. Our results demonstrate a critical role for preoptic gene expression, as well as circulating steroid hormone levels, in encoding information from the social environment and in shaping adaptive behavior. In addition, they provide further evidence for a role of D2R in context-dependent behavior.

},
	author = {Weitekamp, C.A. and Nguyen, J and Hofmann, H. A.}
}
@article {8518,
	title = {Evolution of Animal Neural Systems},
	journal = {Annual Review of Ecology, Evolution, and Systematics},
	volume = {48},
	year = {2017},
	pages = {377-398},
	abstract = {
	Nervous systems are among the most spectacular products of evolution. Their provenance and evolution have been of interest and often the subjects of intense debate since the late nineteenth century. The genomics era has provided researchers with a new set of tools with which to study the early evolution of neurons, and recent progress on the molecular evolution of the first neurons has been both exciting and frustrating. It has become increasingly obvious that genomic data are often insufficient to reconstruct complex phenotypes in deep evolutionary time because too little is known about how gene function evolves over deep time. Therefore, additional functional data across the animal tree are a prerequisite to a fuller understanding of cell evolution. To this end, we review the functional modules of neurons and the evolution of their molecular components, and we introduce the idea of hierarchical molecular evolution.

},
	author = {Liebeskind, BJ and Hofmann, H.A. and Hillis, DA and Zakon, HH}
}
@article {8520,
	title = {The melanocortin system regulates body pigmentation and social behaviour in the cichlid fish Astatotilapia burtoni},
	journal = {Proc R Soc B},
	year = {2017},
	author = {Dijkstra, P.D. and Maguire, S.M. and Harris, R.M. and Rodriguez, A.A. and DeAngelis, R.S. and Flores, S.A. and Hofmann, H.A.}
}
@article {8519,
	title = {A role for oxytocin-like receptor in social habituation in a teleost},
	journal = {Brain, Behavior, and Evolution},
	volume = {89},
	year = {2017},
	pages = {153-161},
	abstract = {
	Oxytocin (OT) mediates social habituation in rodent model systems, but its role in mediating this effect in other vertebrates is unknown. We used males of the African cichlid fish, Astatotilapia burtoni , to investigate two aspects of isotocin (IT; an OT homolog) signaling in social habituation. First, we examined the expression of IT receptor 2 (ITR2) as well as two immediate early genes in brain regions implicated in social recognition. Next, we examined IT neuron activity using immunohistochemistry. Patterns of gene expression in homologs of the amygdala and hippocampus implicate IT signaling in these regions in social habituation to a territorial neighbor. In the preoptic area, the expression of the ITR2 subtype and IT neuron activity respond to the presence of a male, independent of familiarity. Our results implicate IT in mediating social habituation in a teleost.

},
	author = {Weitekamp, C.A. and Solomon-Lane, TK and Del Valle, P and Triki, Z and Nugent, BM and Hofmann, H. A.}
}
@inbook {7711,
	title = {Chapter 15: Brain Evolution, Development, and Plasticity},
	booktitle = {The Wiley Handbook of Evolutionary Neuroscience},
	year = {2017},
	pages = {422-443},
	publisher = {John Wiley \& Sons, Ltd},
	organization = {John Wiley \& Sons, Ltd},
	edition = {1},
	author = {Harris, R.M. and O{\textquoteright}Connell, L.A. and Hofmann, H.A.},
	editor = {Shepherd, S.V.}
}
@article {7684,
	title = {Neuromolecular correlates of cooperation and conflict during territory defense in a cichlid fish},
	journal = {Hormones and Behavior},
	volume = {89},
	year = {2017},
	pages = {145-156},
	abstract = {Cooperative behavior is widespread among animals, yet the neural mechanisms have not been studied in detail. We examined cooperative territory defense behavior and associated neural activity in candidate forebrain regions in the cichlid fish,\&nbsp;Astatotilapia burtoni. We find that a territorial male neighbor will engage in territory defense dependent on the perceived threat of the intruder. The resident male, on the other hand, engages in defense based on the size and behavior of his partner, the neighbor. In the neighbor, we find that an index of engagement correlates with neural activity in the putative homolog of the mammalian basolateral amygdala and in the preoptic area, as well as in preoptic dopaminergic neurons. In the resident, neighbor behavior is correlated with neural activity in the homolog of the mammalian hippocampus. Overall, we find distinct neural activity patterns between the neighbor and the resident, suggesting that an individual perceives and processes an intruder challenge differently during cooperative territory defense depending on its own behavioral role.},
	url = {http://www.sciencedirect.com/science/article/pii/S0018506X16302616},
	author = {Weitekamp, Chelsea A. and Hofmann, Hans A.}
}
@inbook {7559,
	title = {Brain Systems Underlying Social Behavior},
	booktitle = {Evolution of Nervous Systems},
	volume = {1},
	year = {2017},
	pages = {327-334},
	publisher = {Elsevier},
	organization = {Elsevier},
	edition = {2},
	address = {Oxford},
	abstract = {Recent progress in animal behavior research, based on the insight that proximate mechanisms both shape and constrain behavioral responses to natural and sexual selection, has reinforced the importance of knowing the neuromolecular basis of social behavior for understanding its evolution. Here, we review the current state of knowledge of the neural substrates of vertebrate social behavior, with an emphasis on the neuroendocrine and neurochemical pathways involved. Using an integrative perspective, we then discuss the evolution of these mechanisms and highlight several challenges that have hampered progress in this area. Finally, we provide a road map for an integrative evolutionary neuroethology.},
	author = {Weitekamp, C.A. and Hofmann, H. A.},
	editor = {Kaas, J.}
}
@article {7479,
	title = {Dissecting the transcriptional patterns of social dominance across teleosts},
	journal = {Integrative and Comparative Biology},
	volume = {56},
	year = {2016},
	month = {2016},
	pages = {1250-1265},
	abstract = {In many species, under varying ecological conditions, social interactions among individuals result in the formation of dominance hierarchies. Despite general similarities, there are robust differences among dominance hierarchies across species, populations, environments, life stages, sexes, and individuals. Understanding the proximate mechanisms underlying the variation is an important step toward understanding the evolution of social behavior. However, physiological changes associated with dominance, such as gonadal maturation and somatic growth, often complicate efforts to identify the specific underlying mechanisms. Traditional gene expression analyses are useful for generating candidate gene lists, but are biased by choice of significance cut-offs and difficult to use for between-study comparisons. In contrast, complementary analysis tools allow one to both test a priori hypotheses and generate new hypotheses. Here we employ a meta-analysis of high-throughput expression profiling experiments to investigate the gene expression patterns that underlie mechanisms and evolution of behavioral social phenotypes. Specifically, we use a collection of datasets on social dominance in fish across social contexts, sex, and species. Using experimental manipulation to produce female dominance hierarchies in the cichlid Astatotilapia burtoni, heralded as a genomic model of social dominance, we generate gene lists, and assess molecular gene modules. In the dominant female gene expression profile, we demonstrate a strong pattern of up-regulation of genes previously identified as having male-biased expression and furthermore, compare expression biases between male and female dominance phenotypes. Using a threshold-free approach to identify correlation throughout ranked gene lists, we query previously published datasets associated with maternal behavior, alternative reproductive tactics, cooperative breeding, and sex-role reversal to describe correlations among these various neural gene expression profiles associated with different instances of social dominance. These complementary approaches capitalize on the high-throughput gene expression profiling from similar behavioral phenotypes in order to address the mechanisms associated with social dominance behavioral phenotypes.},
	url = {http://icb.oxfordjournals.org/content/56/6/1250.full.pdf?keytype=ref\&ijkey=kgyCjxohpLRxpvr},
	author = {Renn, S C P and O{\textquoteright}Rourke, C.F. and Aubin-Horth, N. and Fraser, E.J. and Hofmann, H. A.}
}
@article {7477,
	title = {The Global Challenge in Neuroscience Education and Training: The MBL Perspective},
	journal = {Neuron},
	volume = {92},
	year = {2016},
	month = {2 Nov, 2016},
	pages = {632-636},
	abstract = {The greatest challenge in moving neuroscience research forward in the 21st century is recruiting, training, and retaining the brightest, rigorous, and most diverse scientists. The MBL research training courses Neurobiology and Neural Systems \&amp; Behavior, and the Summer Program in Neuroscience, Excellence, and Success provide a model for full immersion, discovery-based training while enhancing cultural, geographic, and racial diversity.},
	url = {http://ac.els-cdn.com/S0896627316307760/1-s2.0-S0896627316307760-main.pdf?_tid=1d7ffdb0-b80f-11e6-9625-00000aacb35d\&acdnat=1480628754_f73ed9ab397f33493b184caf4919be23},
	author = {Nishi, Rae and Castaneda, Edward and Davis, Graeme W. and Fenton, Andre A. and Hofmann, Hans A. and King, Jean and Ryan, Timothy A. and Trujillo, Keith A.}
}
@article {7476,
	title = {Inhibition of Aromatase Induces Partial Sex Change in a Cichlid Fish: Distinct Functions for Sex Steroids in Brains and Gonads},
	journal = {Sexual Development},
	volume = {10},
	year = {2016},
	month = {18 Feb, 2016},
	pages = {97-110},
	abstract = {\&nbsp;Sex steroids are major drivers of sexual development and also responsible for the maintenance of the established gender. Especially fishes exhibit great plasticity and less conservation in sex determination and sexual development compared to other vertebrate groups. In addition, fishes have a constant sex steroid production throughout their entire lifespan, which makes them particularly susceptible to interferences with the endogenous sex steroid system. This susceptibility has recently been used to show that inhibition of the key enzyme of estrogen synthesis, aromatase Cyp19a1, can induce functional sex reversal even in adult fish. Here, we investigated the impact of the aromatase inhibitor (AI) fadrozole in adult females of the East African cichlid fish Astatotilapia burtoni. Using gene expression, phenotypic measurements, behavioral experiments, and hormone measurements, we assessed if females treated with fadrozole develop a male-like phenotype. We found that AI treatment has a different effect on gene expression in the gonad compared to the brain, the 2 tissues mostly implicated in sexual development. In contrast to observations in other gonochoristic species, A. burtoni ovaries cannot be transformed into functional testis by AI. However, rapid changes towards a male-like phenotype can be induced with AI in coloration, hormone levels, and behavior.\&nbsp;},
	url = {http://www.karger.com/Article/Pdf/445463},
	author = {Goppert, Carolin and Harris, Rayna M. and Theis, Anya and Boila, Anna and Hohl, Simon and Ruegg, Attila and Hofmann, Hans A. and Salzburger, Walter and Bohne, Astrid}
}
@article {7475,
	title = {Neuroendocrine profiles associated with discrete behavioural variation in Symphodus ocellatus, a species with male alternative reproductive tactics},
	journal = {Molecular Ecology},
	volume = {25},
	number = {20},
	year = {2016},
	month = {October 2016},
	pages = {5212-5227},
	abstract = {The molecular mechanisms underlying phenotypic plasticity are not well understood. Identifying mechanisms underlying alternative reproductive tactics (ARTs) in species for which the behavioural and fitness consequences of this variation are well characterized provides an opportunity to integrate evolutionary and mechanistic understanding of the maintenance of variation within populations. In the ocellated wrasse\&nbsp;Symphodus ocellatus, the behavioural phenotypes of three distinct male morphs (sneakers, satellites and nesting males), which arise from a single genome, have been thoroughly characterized. To determine the neuroendocrine and genomic mechanisms associated with discrete phenotypic variation and ARTs in\&nbsp;S.\&nbsp;ocellatus\&nbsp;in their natural environment, we constructed a whole-brain\&nbsp;de novo\&nbsp;transcriptome and compared global patterns of gene expression between sexes and male morphs. Next, we quantified circulating cortisol and 11-ketotestosterone (11-kt), mediators of male reproductive behaviours, as well as stress and gonadal steroid hormone receptor expression in the preoptic area, ventral subpallial division of the telencephalon and dorsolateral telencephalon, critical brain regions for social and reproductive behaviours. We found higher levels of 11-kt in nesting males and higher levels of cortisol in sneaker males relative to other male morphs and females. We also identified distinct patterns of brain region-specific hormone receptor expression between males such that most hormone receptors are more highly expressed in satellites and nesting males relative to sneakers and females. Our results establish the neuroendocrine and molecular mechanisms that underlie ARTs in the wild and provide a foundation for experimentally testing hypotheses about the relationship between neuromolecular processes and reproductive success.},
	url = {http://onlinelibrary.wiley.com/doi/10.1111/mec.13828/full},
	author = {Nugent, BM and Stiver, KA and Alonzo, SH and Hofmann, H. A.}
}
@article {7481,
	title = {Optimization of next-generation sequencing transcriptome annotation for species lacking sequenced genomes},
	journal = {Molecular Ecology Resources},
	volume = {16},
	year = {2016},
	pages = {446-458},
	abstract = {Next-generation sequencing methods, such as RNA-seq, have permitted the exploration of gene expression in a rangeof organisms which have been studied in ecological contexts but lack a sequenced genome. However, the efficacyand accuracy of RNA-seq annotation methods using reference genomes from related species have yet to be robustlycharacterized. Here we conduct a comprehensive power analysis employing RNA-seq data from Drosophila melano-gaster in conjunction with 11 additional genomes from related Drosophila species to compare annotation methodsand quantify the impact of evolutionary divergence between transcriptome and the reference genome. Our analysesdemonstrate that, regardless of the level of sequence divergence, direct genome mapping (DGM), where transcriptshort reads are aligned directly to the reference genome, significantly outperforms the widely used de novo andguided assembly-based methods in both the quantity and accuracy of gene detection. Our analysis also reveals thatDGM recovers a more representative profile of Gene Ontology functional categories, which are often used to inter-pret emergent patterns in genomewide expression analyses. Lastly, analysis of available primate RNA-seq datademonstrates the applicability of our observations across diverse taxa. Our quantification of annotation accuracy andreduced gene detection associated with sequence divergence thus provides empirically derived guidelines for thedesign of future gene expression studies in species without sequenced genomes.},
	url = {http://onlinelibrary.wiley.com/doi/10.1111/1755-0998.12465/epdf},
	author = {Ockendon, Nina F and O{\textquoteright}Connell, Lauren A. and Bush, Stephen, J. and Monzonsandoval, Jimena and Barnes, Holly and Szekely, Tamas and Hofmann, Hans A. and Dorus, Steve and Urrutia, Araxi O}
}
@article {7480,
	title = {The social and ecological costs of an "over-extended" phenotype},
	journal = {Proceedings of the Royal Society B},
	volume = {283},
	year = {2016},
	month = {6 Jan, 2016},
	pages = {20152359},
	abstract = {
Extended phenotypes offer a unique opportunity to experimentally manipulate and identify sources of selection acting on traits under natural conditions. The social cichlid fish\&nbsp;Neolamprologus multifasciatus\&nbsp;builds nests by digging up aquatic snail shells, creating an extended sexual phenotype that is highly amenable to experimental manipulation through addition of extra shells. Here, we find sources of both positive sexual selection and opposing natural selection acting on this trait; augmenting shell nests increases access to mates, but also increases social aggression and predation risk. Increasing the attractiveness of one male also changed social interactions throughout the social network and altered the entire community structure. Manipulated males produced and received more displays from neighbouring females, who also joined augmented male territories at higher rates than unmanipulated groups. However, males in more attractive territories received more aggression from neighbouring males, potentially as a form of social policing. We also detected a significant ecological cost of the {\textquoteleft}over-extended{\textquoteright} phenotype; heterospecific predators usurped augmented nests at higher rates, using them as breeding sites and displacing residents. Using these natural experiments, we find that both social and ecological interactions generate clear sources of selection mediating the expression of an extended phenotype in the wild.

},
	url = {http://rspb.royalsocietypublishing.org/content/283/1822/20152359},
	author = {Jordan, L.A. and Maguire, S.M. and Hofmann, H. A. and Kohda, M.}
}
@article {7365,
	title = {Complex Homology and the Evolution of Nervous Systems},
	journal = {Trends in Ecology and Evolution},
	volume = {31},
	number = {2},
	year = {2016},
	month = {2016///},
	pages = {127 - 135},
	publisher = {Elsevier Ltd},
	abstract = {We examine the complex evolution of animal nervous systems and discuss the ramifications of this complexity for inferring the nature of early animals. Although reconstructing the origins of nervous systems remains a central challenge in biology, and the phenotypic complexity of early animals remains controversial, a compelling picture is emerging. We now know that the nervous system and other key animal innovations contain a large degree of homoplasy, at least on the molecular level. Conflicting hypotheses about early nervous system evolution are due primarily to differences in the interpretation of this homoplasy. We highlight the need for explicit discussion of assumptions and discuss the limitations of current approaches for inferring ancient phenotypic states.},
	isbn = {0169534715},
	url = {http://dx.doi.org/10.1016/j.tree.2015.12.005},
	author = {Liebeskind, Benjamin J and Hillis, David M and Zakon, Harold H and Hofmann, Hans A.}
}
@article {7384,
	title = {New Frontiers in the Integrative Study of Animal Behavior: Nothing in Neuroscience Makes Sense Except in the Light of Behavior},
	journal = {Integrative and Comparative Biology},
	year = {2016},
	month = {2016///},
	pages = {icw127 - icw127},
	url = {http://icb.oxfordjournals.org/lookup/doi/10.1093/icb/icw127},
	author = {Hofmann, Hans A. and Renn, Suzy C. P. and Rubenstein, Dustin R.}
}
@article {7483,
	title = {Copy number variation in the melanocortin 4 receptor gene and alternative reproductive tactics the swordtail Xiphophorus multilineatus},
	journal = {Environmental Biology of Fishes},
	volume = {98},
	number = {1},
	year = {2015},
	month = {Jan 2015},
	pages = {23-33},
	abstract = {Alternative reproductive tactics are powerful examples of how variation in genetics and physiology among individuals can lead to striking diversity in phenotype. In the swordtails (genus\&nbsp;Xiphophorus), copy number variation (CNV) at the melanocortin 4 receptor (mc4r) locus is correlated with male body size, which in turn is correlated with male mating behavior. We measured the relationship between\&nbsp;mc4r\&nbsp;CNV, behavior, and 11-ketotesterone (11-KT) in\&nbsp;X. multilineatus\&nbsp;to determine whether\&nbsp;mc4r\&nbsp;CNV was associated with other components of male tactics in addition to body size. We confirmed the results of previous studies, showing that male size increases with\&nbsp;mc4r\&nbsp;CNV and that mating behavior toward females was size-dependent. We also examined agonistic behavior by exposing males to their mirror image and found that male-male displays behavior were size-dependent. Small males were less likely to exhibit an agonistic response, suggesting that alternative reproductive tactics span intrasexual and intersexual contexts. There was no significant association between\&nbsp;mc4r\&nbsp;CNV and behavior or 11-KT hormone titer.\&nbsp;Mc4r\&nbsp;CNV is thus associated with the variation in male body size, but not with other traits independent of body size.},
	url = {http://link.springer.com/article/10.1007/s10641-014-0234-y},
	author = {Smith, C. C. and Harris, R. M. and Lampert, K. P. and Schartl, M. and Hofmann, H. A. and Ryan, M. J.}
}
@article {7478,
	title = {Integrating resource defence theory with a neural nonapeptide pathway to explain territory-based mating systems},
	journal = {Frontiers in Zoology},
	volume = {12(Suppl 1)},
	year = {2015},
	month = {24 Aug, 2015},
	pages = {S16},
	abstract = {The ultimate-level factors that drive the evolution of mating systems have been well studied, but an evolutionarily conserved neural mechanism involved in shaping behaviour and social organization across species has remained elusive. Here, we review studies that have investigated the role of neural arginine vasopressin (AVP), vasotocin (AVT), and their receptor V1a in mediating variation in territorial behaviour. First, we discuss how aggression and territoriality are a function of population density in an inverted-U relationship according to resource defence theory, and how territoriality influences some mating systems. Next, we find that neural AVP, AVT, and V1a expression, especially in one particular neural circuit involving the lateral septum of the forebrain, are associated with territorial behaviour in males of diverse species, most likely due to their role in enhancing social cognition. Then we review studies that examined multiple species and find that neural AVP, AVT, and V1a expression is associated with territory size in mammals and fishes. Because territoriality plays an important role in shaping mating systems in many species, we present the idea that neural AVP, AVT, and V1a expression that is selected to mediate territory size may also influence the evolution of different mating systems. Future research that interprets proximate-level neuro-molecular mechanisms in the context of ultimate-level ecological theory may provide deep insight into the brain-behaviour relationships that underlie the diversity of social organization and mating systems seen across the animal kingdom.},
	url = {http://download.springer.com/static/pdf/257/art\%253A10.1186\%252F1742-9994-12-S1-S16.pdf?originUrl=http\%3A\%2F\%2Ffrontiersinzoology.biomedcentral.com\%2Farticle\%2F10.1186\%2F1742-9994-12-S1-S16\&token2=exp=1480629806~acl=\%2Fstatic\%2Fpdf\%2F257\%2Fart\%25253A10.11},
	author = {Oldfield, Ronald G. and Harris, Rayna M. and Hofmann, Hans A.}
}
@article {7482,
	title = {Parental care in the Cuatro Ci{\'e}negas cichlid, Herichthys minckleyi (Teleostei: Cichlidae)},
	journal = {Hydrobiologia},
	volume = {748},
	number = {1},
	year = {2015},
	month = {April 2015},
	pages = {233-257},
	abstract = {Behavioral studies have often examined parental care by measuring phenotypic plasticity of behavior within a species. Phylogenetic studies have compared parental care among species, but only at broad categories (e.g., care vs. no care). Here we provide a detailed account that integrates phylogenetic analysis with quantitative behavioral data to better understand parental care behavior in the Cuatro Ci{\'e}negas cichlid, Herichthys minckleyi. We found that H. minckleyi occurs in a clade of sexually monochromatic or weakly dichromatic monogamous species, but that male and female H. minckleyi have dramatically different reproductive coloration patterns, likely as a result of sexual selection. Furthermore, we found that males are polygynous; large males guard large territories, and smaller males may attempt alternative mating tactics (sneaking). Finally, compared to the closely related monogamous Rio Grande cichlid, H. cyanoguttatus, males of H. minckleyi were present at their nests less often and performed lower rates of aggressive offspring defense, and females compensated for the absence of their mates by performing higher levels of offspring defense. Body color, mating system, and parental care in H. minckleyi appear to have evolved after it colonized Cuatro Ci{\'e}negas, and are likely a result of evolution in an isolated, stable environment.},
	url = {http://link.springer.com/article/10.1007/s10750-014-2081-4},
	author = {Oldfield, Ronald, G. and Mandrekar, Kapil and Nieves, M. Xavier and Hendrickson, Dean A. and Chakrabarty, Prosanta and Swanson, Brook O. and Hofmann, Hans A.}
}
@article {7366,
	title = {Arginine vasotocin regulates social ascent in the African cichlid fish Astatotilapia burtoni},
	journal = {General and Comparative Endocrinology},
	volume = {212},
	year = {2015},
	month = {2015///},
	pages = {106 - 113},
	publisher = {Elsevier Inc.},
	abstract = {Neuropeptides modulate many aspects of behavior and physiology in a broad range of animals. Arginine vasotocin (AVT) is implicated in mediating social behavior in teleost fish, although its specific role varies between species, sexes, life stages, and social context. To investigate whether the effects of AVT on behavior depend on social context, we used the African cichlid fish Astatotilapia burtoni, which is well-known for its remarkable behavioral plasticity. We pharmacologically manipulated the AVT system in established socially dominant and subordinate A. burtoni males, as well as in males ascending to dominance status in a socially unstable environment. Our results show that exogenous AVT causes a stress response, as evidenced by reduced behavioral activity and increased circulating levels of cortisol in established dominant and subordinate males. Administration of the AVT antagonist Manning compound, on the other hand, did not affect established subordinate or dominant males. However, AVT antagonist-treated males ascending from subordinate to dominant status exhibited reduced aggressive and increased courtship behavior compared to vehicle-treated animals. Finally, we measured circulating cortisol levels and brain gene expression levels of AVT and its behaviorally relevant V1a2 receptor in all three social phenotypes and found that plasma cortisol and mRNA levels of both genes were increased in ascending males compared to dominant and subordinate males. Our results provide a more detailed understanding of the role of the AVT system in the regulation of complex behavior in a dynamically changing social environment.},
	keywords = {Aggression, Manning compound, Nonapeptides, Plasticity, Social dominance},
	url = {http://dx.doi.org/10.1016/j.ygcen.2014.03.004},
	author = {Huffman, Lin S. and Hinz, Flora I. and Wojcik, Sophie and Aubin-Horth, Nadia and Hofmann, Hans A.}
}
@article {7369,
	title = {Neural Gene Expression Profiles and Androgen Levels Underlie Alternative Reproductive Tactics in the Ocellated Wrasse, Symphodus ocellatus},
	journal = {Ethology},
	volume = {121},
	number = {2},
	year = {2015},
	month = {2015///},
	pages = {152 - 167},
	abstract = {Discrete variation in reproductive behavior and physiology is observed in diverse taxa. Although it is known that most within-sex alternative reproductive tactics arise as a consequence of phenotypic plasticity, relatively little is known about differential neural gene expression among plastic alternative reproductive phenotypes. In the ocellated wrasse Symphodus ocellatus, males exhibit one of three alternative tactics (nesting, satellite, and sneaker) within a reproductive season, but switch tactics between years. Satellites and sneakers spawn parasitically in dominant (nesting) males{\textquoteright} nests, but only nesting males provide parental care. Nesting and satellite males show transient cooperative defense of nests against sneakers. Here, we analyze circulating sex steroid hormone levels and neural gene expression profiles in these three male phenotypes and in females. 11-ketotestosterone (but not testosterone) was highest in nesting males, while estradiol was highest in females. Brain transcriptomes of satellites and females were most similar to each other and intermediate to nesting and sneaker males. Sneakers showed more total expression differences, whereas nesting males showed higher magnitude expression differences. Our findings reveal the surprising extent to which neural gene expression patterns vary across reproductive tactics that vary in a number of social traits, including aggression, territoriality, and cooperation, providing important insights into the molecular mechanisms that may underlie variation in cooperative and reproductive behavior.},
	keywords = {Androgens, competition, Cooperation, Mating tactic, Microarray, Reproduction},
	author = {Stiver, Kelly A. and Harris, Rayna M. and Townsend, Jeffrey P. and Hofmann, Hans A. and Alonzo, Suzanne H.}
}
@article {7368,
	title = {Seeing is believing: dynamic evolution of gene families},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {112},
	number = {5},
	year = {2015},
	month = {2015///},
	pages = {1252 - 1253},
	abstract = {Educated by his deep appreciation of nature, Darwin observed that "from so simple a beginning endless forms most beautiful" have arisen throughout the evolutionary history of life on earth (1). The spectacular diversity of orchids (2) and beetles (3) has long fascinated naturalists and casual observers alike. More recently, the adaptive radiations of Hawaiian drosophilids (4), Caribbean Anolis lizards (5), and African cichlid fishes (6) have become prime examples for understanding the mechanisms that enable diversification. Gene duplication and deletion are generally considered important evolutionary mechanisms that give rise to phenotypic diversity (7). Following gene duplication and loss, adaptation and speciation appear to proceed through a combination of both structural and cis-regulatory changes in one or more paralogous genes (8). Recent advances in sequencing technology have enabled researchers to make significant progress in understanding the molecular evolution that has facilitated diversification. In PNAS, Cortesi et al. (9) examine the evolution of vertebrate opsin genes as a spectacular example of how gene duplication and deletion events that affect spectral sensitivity have driven adaptation to diverse light environments and visual displays.},
	author = {Harris, Rayna M. and Hofmann, Hans A.}
}
@article {7370,
	title = {Social odors conveying dominance and reproductive information induce rapid physiological and neuromolecular changes in a cichlid fish},
	journal = {BMC Genomics},
	volume = {16},
	number = {1},
	year = {2015},
	month = {2015///},
	pages = {1 - 13},
	abstract = {Social plasticity is a pervasive feature of animal behavior. Animals adjust the expression of their social behavior to the daily changes in social life and to transitions between life-history stages, and this ability has an impact in their Darwinian fitness. This behavioral plasticity may be achieved either by rewiring or by biochemically switching nodes of the neural network underlying social behavior in response to perceived social information. Independent of the proximate mechanisms, at the neuromolecular level social plasticity relies on the regulation of gene expression, such that different neurogenomic states emerge in response to different social stimuli and the switches between states are orchestrated by signaling pathways that interface the social environment and the genotype. Here, we test this hypothesis by characterizing the changes in the brain profile of gene expression in response to social odors in the Mozambique Tilapia, Oreochromis mossambicus. This species has a rich repertoire of social behaviors during which both visual and chemical information are conveyed to conspecifics. Specifically, dominant males increase their urination frequency during agonist encounters and during courtship to convey chemical information reflecting their dominance status.},
	keywords = {cichlid, correspondence, ispa, jsimoes, Microarray, olfaction, olfactory bulb, pt, telencephalon, transcriptomics},
	isbn = {1471-2164 (Electronic)
1471-2164 (Linking)},
	url = {http://dx.doi.org/10.1186/s12864-015-1255-4},
	author = {Sim{\~o}es, Jos{\'e} M and Barata, Eduardo N and Harris, Rayna M. and O{\textquoteright}Connell, Lauren A. and Hofmann, Hans A. and Oliveira, Rui F}
}
@article {7371,
	title = {Taxon matters: Promoting integrative studies of social behavior: NESCent Working Group on Integrative Models of Vertebrate Sociality: Evolution, Mechanisms, and Emergent Properties},
	journal = {Trends in Neurosciences},
	volume = {38},
	number = {4},
	year = {2015},
	month = {2015///},
	pages = {189 - 191},
	abstract = {The neural and molecular mechanisms underlying social behavior - including their functional significance and evolution - can only be fully understood using data obtained under multiple social, environmental, and physiological conditions. Understanding the complexity of social behavior requires integration across levels of analysis in both laboratory and field settings. However, there is currently a disconnect between the systems studied in the laboratory versus the field. We argue that recent conceptual and technical advances provide exciting new opportunities to close this gap by making non-model organisms accessible to modern approaches in both laboratory and nature.},
	keywords = {Ecology, Evolution, Integration, Model species, Neural and endocrine mechanisms, Sociality},
	isbn = {1878-108X (Electronic)\r0166-2236 (Linking)},
	author = {Taborsky, Michael and Hofmann, Hans A. and Beery, Annaliese K. and Blumstein, Daniel T. and Hayes, Loren D. and Lacey, Eileen A. and Martins, Em{\'\i}lia P. and Phelps, Steven M. and Solomon, Nancy G. and Rubenstein, Dustin R.}
}
@article {7367,
	title = {Testing the critical window hypothesis of timing and duration of estradiol treatment on hypothalamic gene networks in reproductively mature and aging female rats},
	journal = {Endocrinology},
	volume = {156},
	number = {8},
	year = {2015},
	month = {2015///},
	pages = {2918 - 2933},
	abstract = {At menopause, the dramatic loss of ovarian estradiol (E2) necessitates the adaptation of estrogen-sensitive neurons in the hypothalamus to an estrogen-depleted environment. We developed a rat model to test the "critical window" hypothesis of the effects of timing and duration of E2 treatment after deprivation on the hypothalamic neuronal gene network in the arcuate nucleus and the medial preoptic area. Rats at 2 ages (reproductively mature or aging) were ovariectomized and given E2 or vehicle replacement regimes of differing timing and duration. Using a 48-gene quantitative low-density PCR array and weighted gene coexpression network analysis, we identified gene modules differentially regulated by age, timing, and duration of E2 treatment. Of particular interest, E2 status differentially affected suites of genes in the hypothalamus involved in energy balance, circadian rhythms, and reproduction. In fact, E2 status was the dominant factor in determining gene modules and hormone levels; age, timing, and duration had more subtle effects. Our results highlight the plasticity of hypothalamic neuroendocrine systems during reproductive aging and its surprising ability to adapt to diverse E2 replacement regimes.},
	author = {Yin, Weiling and Maguire, Sean M. and Pham, Brian and Garcia, Alexandra N. and Dang, Nguyen Vy and Liang, Jingya and Wolfe, Andrew and Hofmann, Hans A. and Gore, Andrea C}
}
@article {7561,
	title = {Neurogenomics of Behavioral Plasticity},
	journal = {Advances in Experimental Medicine and Biology},
	volume = {781},
	year = {2014},
	month = {January 2014},
	pages = {149-168},
	abstract = {Across animals, there is remarkable diversity in behavior. Modern genomic approaches have made it possible to identify the molecular underpinnings of varied behavioral phenotypes. By examining species with plastic phenotypes we have begun to understand the dynamic and flexible nature of neural transcriptomes and identified gene modules associated with variation in social and reproductive behaviors in diverse species. Importantly, it is becoming increasingly clear that some candidate genes and gene networks are involved in complex social behaviors across even divergent species, yet few comparative transcriptomics studies have been conducted that examine a specific behavior across species. We discuss the implications of a range of important and insightful studies that have increased our understanding of the neurogenomics of behavioral plasticity. Despite its successes, behavioral genomics has been criticized for its lack of hypotheses and causative insights. We propose here a novel avenue to overcome some of these short-comings by complementing "forward genomics" studies (i.e., from phenotype to behaviorally relevant gene modules) with a "reverse genomics" approach (i.e., manipulating novel gene modules to examine effects on behavior, hormones, and the genome itself) to examine the functional causes and consequences of differential gene expression patterns. We discuss how several established approaches (such as pharmacological manipulations of a novel candidate pathway, fine scale mapping of novel candidate gene expression in the brain, or identifying direct targets of a novel transcription factor of interest) can be used in combination with the analysis of the accompanying neurogenomic responses to reveal unexpected biological processes. The integration of forward and reverse genomics will move the field beyond statistical associations and yield great insights into the neural and molecular control of social behavior and its evolution.},
	url = {https://www.ncbi.nlm.nih.gov/pubmed/24277299},
	author = {Harris, R. M. and Hofmann, H. A.}
}
@article {7484,
	title = {The genomic substrate for adaptive radiation in African cichlid fish},
	journal = {Nature},
	volume = {513},
	year = {2014},
	pages = {375-381},
	abstract = {Cichlid fishes are famous for large, diverse and replicated adaptive radiations in the Great Lakes of East Africa. To understand themolecularmechanisms underlying cichlid phenotypic diversity,wesequenced the genomesand transcriptomes of five lineages of Africancichlids: theNile tilapia (Oreochromis niloticus), an ancestral lineagewith low diversity; and four members of the East African lineage: Neolamprologus brichardi/pulcher (older radiation, Lake Tanganyika), Metriaclima zebra (recent radiation, LakeMalawi),Pundamilia nyererei (very recent radiation, LakeVictoria), andAstatotilapia burtoni (riverine species around Lake Tanganyika).Wefound an excess of gene duplications in the East African lineage compared to tilapia and other teleosts, an abundance of non-coding element divergence, accelerated coding sequence evolution, expression divergence associated with transposable element insertions, and regulation by novel microRNAs. In addition, we analysed sequence data from sixty individuals representing six closely related species from Lake Victoria, and show genome-wide diversifying selection on coding and regulatory variants, some of which were recruited fromancient polymorphisms. Weconclude that a numberof molecular mechanisms shaped East African cichlid genomes, and that amassing of standing variation during periods of relaxed purifying selectionmayhave been important in facilitating subsequent evolutionary diversification.},
	url = {http://www.nature.com/nature/journal/v513/n7518/pdf/nature13726.pdf},
	author = {Brewand, D. and Wagner, C.E. and Li, Y.I. and Malinsky, M. and Keller, I. and Fan, S. and Simakov, O. and Ng, A.Y. and Lim, Z.W. and Bezault, E. and Turner-Maier, J. and Johnson, J. and Alcazar, R. and Noh, H.J. and Russell, P. and Aken, B. and Alfodi, J. and Amemiya, C. and Azzouzi, N. and Baroiller, J.F. and Barloy-Hubler, F. and Berlin, A. and Bloomquist, R. and Carleton, K.L. and Conte, M.a. and D{\textquoteright}Cotta, H. and Eshel, O. and Gaffney, L. and Galibert, F. and Grante, H.F. and Gnerre, S. and Greuter, L. and Guyon, R. and Haddad, N.S. and Haerty, W. and Harris, R. M. and Hofmann, H. A. and Hourlier, T. and Hulata, G. and Jaffe, D.B. and Lara, M. and Lee, A.P. and MacCallum, I. and Mwaiko, S. and Nikaido, M. and Nishihara, H. and Ozouf-Costaz, C. and Penman, D.J. and Przybylski, D. and Rakotomanga, M. and Renn, S.C. and Ribeiro, F.J. and Ron, M. and Salzburger, W and Sanchez-Pulido, L. and Santos, M.E. and Searle, S. and Sharpe, T. and Swofford, R. and Tan, F.J. and Williams, L. and Young, S. and Yin, S and Okada, N. and Kocher, T.D. and Miska, E.a. and Lander, E.S. and Venkatesh, B. and Fernald, R D and Meyer, A. and Ponting, C.P. and Streelman, J.T. and Lindblad-Toh, K. and Seehausen, O. and Di Palmer, F.}
}
@article {7378,
	title = {Complex structural and regulatory evolution of the pro-opiomelanocortin gene family},
	journal = {General and Comparative Endocrinology},
	volume = {195},
	year = {2014},
	month = {2014///},
	pages = {107 - 115},
	publisher = {Elsevier Inc.},
	abstract = {The melanocortin system is a neuroendocrine machinery that has been associated with phenotypic diversification in a number of vertebrate lineages. Central to the highly pleiotropic melanocortin system is the pro-opiomelanocortin (pomc) gene family, a family of pre-prohormones that each give rise to melanocyte stimulating hormone (MSH), adrenocorticotropic releasing hormone (ACTH), ??-lipotropin hormone, and ??-endorphin. Here we examine the structure, tissue expression profile, and pattern of cis transcriptional regulation of the three pomc paralogs (??1, ??2, and ??) in the model cichlid fish Astatotilapia burtoni and other cichlids, teleosts, and mammals. We found that the hormone-encoding regions of pomc ??1, pomc ??2 and pomc ?? are highly conserved, with a few notable exceptions. Surprisingly, the pomc ?? gene of cichlids and pomacentrids (damselfish) encodes a novel melanocortin peptide, ??-MSH, as a result of a tandem duplication of the segment encoding ACTH. All three genes are expressed in the brain and peripheral tissues, but pomc ??1 and ??2 show a more spatially restricted expression profile than pomc ??. In addition, the promoters of each pomc gene have diverged in nucleotide sequence, which may have facilitated the diverse tissue-specific expression profiles of these paralogs across species. Increased understanding of the mechanisms regulating pomc gene expression will be invaluable to the study of pomc in the context of phenotypic evolution. ?? 2013 Elsevier Inc.},
	keywords = {??-MSH, cichlid, Gene Duplication, Genome duplication, Melanocortin system, Pomc},
	url = {http://dx.doi.org/10.1016/j.ygcen.2013.10.007},
	author = {Harris, Rayna M. and Dijkstra, Peter D. and Hofmann, Hans A.}
}
@article {7379,
	title = {Copy number variation in the melanocortin 4 receptor gene and alternative reproductive tactics the swordtail Xiphophorus multilineatus},
	journal = {Environmental Biology of Fishes},
	volume = {98},
	number = {1},
	year = {2014},
	month = {2014///},
	pages = {23 - 33},
	keywords = {11-Ketotestosterone, Alternative reproductive tactics, Copy number variation, Melanocortin 4 receptor, P-gene, Xiphophorus},
	isbn = {1064101402},
	author = {Smith, C. C. and Harris, R. M. and Lampert, K. P. and Schartl, M. and Hofmann, H. A. and Ryan, M. J.}
}
@article {7381,
	title = {An evolutionary framework for studying mechanisms of social behavior},
	journal = {Trends in Ecology and Evolution},
	volume = {29},
	number = {10},
	year = {2014},
	month = {2014///},
	pages = {581 - 589},
	publisher = {Elsevier Ltd},
	abstract = {
	Social interactions are central to most animals and have a fundamental impact upon the phenotype of an individual. Social behavior (social interactions among conspecifics) represents a central challenge to the integration of the functional and mechanistic bases of complex behavior. Traditionally, studies of proximate and ultimate elements of social behavior have been conducted by distinct groups of researchers, with little communication across perceived disciplinary boundaries. However, recent technological advances, coupled with increased recognition of the substantial variation in mechanisms underlying social interactions, should compel investigators from divergent disciplines to pursue more integrative analyses of social behavior. We propose an integrative conceptual framework intended to guide researchers towards a comprehensive understanding of the evolution and maintenance of mechanisms governing variation in sociality.

},
	keywords = {Complex sociality, Evolution, Genomics, Group-living, Hormones, neural circuits, Social Behavior},
	isbn = {0269-7653},
	url = {http://dx.doi.org/10.1016/j.tree.2014.07.008},
	author = {Hofmann, Hans A. and Beery, Annaliese K. and Blumstein, Daniel T. and Couzin, Iain D. and Earley, Ryan L. and Hayes, Loren D. and Hurd, Peter L. and Lacey, Eileen A. and Phelps, Steven M. and Solomon, Nancy G. and Taborsky, Michael and Young, Larry J. and Rubenstein, Dustin R.}
}
@article {7372,
	title = {Evolutionary themes in the neurobiology of social cognition},
	journal = {Current Opinion in Neurobiology},
	volume = {28},
	year = {2014},
	month = {2014///},
	pages = {22 - 27},
	publisher = {Elsevier Ltd},
	abstract = {Remarkable examples of social cognition have been described across a diverse range of species, yet surprisingly little is known about the neurobiological underpinnings of these behaviors. Recent studies suggest that the molecular pathways and neural networks that mediate social behavior have been relatively conserved across vertebrate evolution, suggesting that shared mechanisms may drive adaptive behavioral responses to social stimuli. Here, we review recent advances in the neurobiology of flexible and context-dependent social behaviors across vertebrate taxa, focusing on female mate choice, pair-bonding, and aggressive behavior. Furthermore, we highlight the outstanding opportunities for uncovering the mechanisms mediating cooperative behavior, an exemplar of social cognition. We suggest a framework for investigating context-dependent neural organization and the evoked neural response to social stimuli. ?? 2014 Elsevier Ltd.},
	isbn = {1873-6882 (Electronic)\r0959-4388 (Linking)},
	url = {http://dx.doi.org/10.1016/j.conb.2014.06.005},
	author = {Weitekamp, Chelsea A. and Hofmann, Hans A.}
}
@article {7374,
	title = {The genomic substrate for adaptive radiation in African cichlid fish},
	journal = {Nature},
	volume = {513},
	year = {2014},
	month = {2014///},
	pages = {375 - 381},
	abstract = {Cichlid fishes are famous for large, diverse and replicated adaptive radiations in the Great Lakes of East Africa. To under- standthemolecularmechanismsunderlying cichlidphenotypic diversity,wesequencedthegenomesandtranscriptomes of fivelineages of Africancichlids: theNile tilapia (Oreochromis niloticus),anancestral lineagewithlowdiversity;andfour members of the East African lineage: Neolamprologus brichardi/pulcher (older radiation, Lake Tanganyika),Metriaclima zebra(recent radiation,LakeMalawi),Pundamilianyererei (veryrecentradiation,LakeVictoria),andAstatotilapiaburtoni (riverine species aroundLakeTanganyika).Wefound an excess of gene duplications in the East African lineagecompared to tilapia and other teleosts, an abundance of non-coding element divergence, accelerated coding sequence evolution, expression divergence associated with transposable element insertions,and regulationby novel microRNAs. In addition, we analysed sequence data from sixty individuals representing six closely related species from Lake Victoria, and show genome-widediversifying selectiononcodingandregulatoryvariants,someofwhichwererecruited fromancientpoly- morphisms.Weconclude that anumberof molecular mechanismsshaped East African cichlid genomes, and that amass- ing of standing variation during periods of relaxed purifying selectionmayhavebeenimportantin facilitating subsequent evolutionary diversification.},
	isbn = {0000017892},
	author = {Brawand, D. and Wagner, C.E. and Li, Y.I. and Malinsky, M. and Keller, I. and Fan, S. and Simakov, O. and Ng, A.Y. and Lim, Z.W. and Bezault, E. and Turner-Maier and J. Johnson, J. and Alcazar, R. and Noh, H.J. and Russell, P. and Aken, B. and Alf{\"o}ldi, J. and Amemiya, C. and Azzouzi, N. and Baroiller, J.-F. and Barloy-Hubler, F. and Berlin, A. and Bloomquist, R. and Carleton, K.L. and Conte, M.a. and D{\textquoteright}Cotta, H. and Eshel, O. and Gaffney, L. and Galibert, F. and Gante, H.F. and Gnerre, S. and Greuter, L. and Guyon, R. and Haddad, N.S. and Haerty, W. and Harris, R. M. and Hofmann, H. A. and Hourlier, T. and Hulata, G. and Jaffe, D.B. and Lara, M. and A.P., Lee. and MacCallum, I. and Mwaiko, S. and Nikaido, M. and Nishihara, H. and Ozouf-Costaz, C. and Penman, D.J. and Przybylski, D. and Rakotomanga, M. and Renn, S C P and Ribeiro, F.J. and Ron, M. and Salzburger, W and Sanchez-Pulido, L. and Santos, M.E. and Searle, S. and Sharpe, T. and Swofford, R. and Tan, F.J. and Williams, L. and Young, S. and Yin, S and Okada, N. and Kocher, T.D. and Miska, E.a. and Lander, E.S. and Venkatesh, B. and Fernald, R D and Meyer, A. and Ponting, C.P. and Streelman, J.T. and Lindblad-Toh, K. and Seehausen, O. and Di Palma, F.}
}
@article {7376,
	title = {NSF workshop report: Discovering general principles of nervous system organization by comparing brain maps across species},
	journal = {Journal of Comparative Neurology},
	volume = {522},
	number = {7},
	year = {2014},
	month = {2014///},
	pages = {1445 - 1453},
	abstract = {Efforts to understand nervous system structure and function have received new impetus from the federal Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative. Comparative analyses can contribute to this effort by leading to the discovery of general principles of neural circuit design, information processing, and gene-structure-function relationships that are not apparent from studies on single species. We here propose to extend the comparative approach to nervous system {\textquoteright}maps{\textquoteright} comprising molecular, anatomical, and physiological data. This research will identify which neural features are likely to generalize across species, and which are unlikely to be broadly conserved. It will also suggest causal relationships between genes, development, adult anatomy, physiology, and, ultimately, behavior. These causal hypotheses can then be tested experimentally. Finally, insights from comparative research can inspire and guide technological development. To promote this research agenda, we recommend that teams of investigators coalesce around specific research questions and select a set of {\textquoteright}reference species{\textquoteright} to anchor their comparative analyses. These reference species should be chosen not just for practical advantages, but also with regard for their phylogenetic position, behavioral repertoire, well-annotated genome, or other strategic reasons. We envision that the nervous systems of these reference species will be mapped in more detail than those of other species. The collected data may range from the molecular to the behavioral, depending on the research question. To integrate across levels of analysis and across species, standards for data collection, annotation, archiving, and distribution must be developed and respected. To that end, it will help to form networks or consortia of researchers and centers for science, technology, and education that focus on organized data collection, distribution, and training. These activities could be supported, at least in part, through existing mechanisms at NSF, NIH, and other agencies. It will also be important to develop new integrated software and database systems for cross-species data analyses. Multidisciplinary efforts to develop such analytical tools should be supported financially. Finally, training opportunities should be created to stimulate multidisciplinary, integrative research into brain structure, function, and evolution.},
	keywords = {Brain evolution, Brain Mapping, Comparative method},
	isbn = {0021-9967; 1096-9861},
	author = {Striedter, Georg F. and Belgard, T. Grant and Chen, Chun Chun and Davis, Fred P. and Finlay, Barbara L. and G{\"u}nt{\"u}rk{\"u}n, Onur and Hale, Melina E. and Harris, Julie A. and Hecht, Erin E. and Hof, Patrick R. and Hofmann, Hans A. and Holland, Linda Z. and Iwaniuk, Andrew N. and Jarvis, Erich D. and Karten, Harvey J. and Katz, Paul S. and Kristan, William B. and Macagno, Eduardo R. and Mitra, Partha P. and Moroz, Leonid L. and Preuss, Todd M. and Ragsdale, Clifton W. and Sherwood, Chet C. and Stevens, Charles F. and St{\"u}ttgen, Maik C. and Tsumoto, Tadaharu and Wilczynski, Walter}
}
@article {7377,
	title = {Parental care in the Cuatro Cienegas cichlid, Herichthys minckleyi (Teleostei: Cichlidae)},
	journal = {Hydrobiologia},
	volume = {748},
	number = {1},
	year = {2014},
	month = {2014///},
	pages = {233 - 257},
	abstract = {Behavioral studies have often examined parental care by measuring phenotypic plasticity of behavior within a species. Phylogenetic studies have compared parental care among species, but only at broad categories (e.g., care vs. no care). Here we provide a detailed account that integrates phylogenetic analysis with quantitative behavioral data to better understand parental care behavior in the Cuatro Ci{\'e}negas cichlid, Herichthys minckleyi. We found that H. minckleyi occurs in a clade of sexually monochromatic or weakly dichromatic monogamous species, but that male and female H. minckleyi have dramatically different reproductive coloration patterns, likely as a result of sexual selection. Furthermore, we found that males are polygynous; large males guard large territories, and smaller males may attempt alternative mating tactics (sneaking). Finally, compared to the closely related monogamous Rio Grande cichlid, H. cyanoguttatus, males of H. minckleyi were present at their nests less often and performed lower rates of aggressive offspring defense, and females compensated for the absence of their mates by performing higher levels of offspring defense. Body color, mating system, and parental care in H. minckleyi appear to have evolved after it colonized Cuatro Ci{\'e}negas, and are likely a result of evolution in an isolated, stable environment.},
	keywords = {Aggression, Cuatro Ci??negas, Herichthys, Mating systems, Polygyny, Sexual selection},
	isbn = {1075001420},
	author = {Oldfield, Ronald G. and Mandrekar, Kapil and Nieves, M. Xavier and Hendrickson, Dean A. and Chakrabarty, Prosanta and Swanson, Brook O. and Hofmann, Hans A.}
}
@article {7380,
	title = {Predator exposure alters stress physiology in guppies across timescales},
	journal = {Hormones and Behavior},
	volume = {65},
	number = {2},
	year = {2014},
	month = {2014///},
	pages = {165 - 172},
	publisher = {Elsevier Inc.},
	abstract = {In vertebrates, glucocorticoids mediate a wide-range of responses to stressors. For this reason, they are implicated in adaptation to changes in predation pressure. Trinidadian guppies ( Poecilia reticulata) from high-predation environments have repeatedly and independently colonized and adapted to low-predation environments, resulting in parallel changes in life history, morphology, and behavior. We validated methods for non-invasive waterborne hormone sample collection in this species, and used this technique to examine genetic and environmental effects of predation on basal glucocorticoid (cortisol) levels. To examine genetic differences, we compared waterborne cortisol levels in high- and low-predation fish from two distinct population pairs. We found that fish from high-predation localities had lower cortisol levels than their low-predation counterparts. To isolate environmental influences, we compared waterborne cortisol levels in genetically similar fish reared with and without exposure to predator chemical cues. We found that fish reared with predator chemical cues had lower waterborne cortisol levels than those reared without. Comparisons of waterborne and whole-body cortisol levels demonstrated that populations differed in overall cortisol levels in the body, whereas rearing conditions altered the release of cortisol from the body into the water. Thus, evolutionary history with predators and lifetime exposure to predator cues were both associated with lower cortisol release, but depended on distinct physiological mechanisms. ?? 2013 Elsevier Inc.},
	keywords = {Adaptive evolution, Cortisol, Glucocorticoids, Poecilia reticulata, Predation, Stress},
	url = {http://dx.doi.org/10.1016/j.yhbeh.2013.12.010},
	author = {Fischer, Eva K. and Harris, Rayna M. and Hofmann, Hans A. and Hoke, Kim L.}
}
@article {7373,
	title = {Single-Neuron gene expression analysis using the Maxwell {\textregistered} 16 LEV System in the neural systems and behavior course},
	journal = {Promega},
	number = {January},
	year = {2014},
	month = {2014///},
	pages = {1 - 6},
	author = {Harris, Rayna M. and Otopalik, Adriane G and Smith, Colin S and Bucher, Dirk and Golowasch, Jorge and Hofmann, Hans A.}
}
@article {7350,
	title = {Arginine vasotocin and androgen pathways are associated with mating system variation in North American cichlid fishes},
	journal = {Hormones and Behavior},
	volume = {64},
	number = {1},
	year = {2013},
	month = {2013///},
	pages = {44 - 52},
	abstract = {Neuroendocrine pathways that regulate social behavior are remarkably conserved across divergent taxa. The neuropeptides arginine vasotocin/vasopressin (AVT/AVP) and their receptor V1a mediate aggression, space use, and mating behavior in male vertebrates. The hormone prolactin (PRL) also regulates social behavior across species, most notably paternal behavior. Both hormone systems may be involved in the evolution of monogamous mating systems. We compared AVT, AVT receptor V1a2, PRL, and PRL receptor PRLR1 gene expression in the brains as well as circulating androgen concentrations of free-living reproductively active males of two closely related North American cichlid species, the monogamous Herichthys cyanoguttatus and the polygynous Herichthys minckleyi. We found that H. cyanoguttatus males bond with a single female and together they cooperatively defend a small territory in which they reproduce. In H. minckleyi, a small number of large males defend large territories in which they mate with several females. Levels of V1a2 mRNA were higher in the hypothalamus of H. minckleyi, and PRLR1 expression was higher in the hypothalamus and telencephalon of H. minckleyi. 11-ketotestosterone levels were higher in H. minckleyi, while testosterone levels were higher in H. cyanoguttatus. Our results indicate that a highly active AVT/V1a2 circuit(s) in the brain is associated with space use and social dominance and that pair bonding is mediated either by a different, less active AVT/V1a2 circuit or by another neuroendocrine system. ?? 2013 Elsevier Inc.},
	keywords = {AVP, AVT, Herichthys, monogamy, polygamy, prolactin, vasopressin},
	isbn = {0018-506x},
	author = {Oldfield, Ronald G. and Harris, Rayna M. and Hendrickson, Dean A. and Hofmann, Hans A.}
}
@article {7383,
	title = {Aromatase regulates aggression in the African cichlid fish Astatotilapia burtoni},
	journal = {Physiology and Behavior},
	volume = {112-113},
	year = {2013},
	month = {2013///},
	pages = {77 - 83},
	publisher = {Elsevier Inc.},
	abstract = {The roles of estrogen and androgens in male social behavior are well studied, but little is known about how these hormones contribute to behavior in a social hierarchy. Here we test the role of aromatase, the enzyme that converts testosterone into estradiol, in mediating aggression and reproductive behavior in male Astatotilapia burtoni, an African cichlid fish that displays remarkable plasticity in social behavior. We first measured aromatase expression in subordinate and dominant males in brain regions that regulate social behavior and found that subordinate males have higher aromatase expression than dominant males in the magnocellular and gigantocellular regions of the preoptic area. Next, we functionally tested the role of aromatase in regulating behavior by intraperitoneally injecting dominant males with either saline or fadrozole (FAD), an aromatase inhibitor, and found that FAD treatment decreases aggressive, but not reproductive, behaviors compared to saline controls. To determine the underlying physiological and molecular consequences of FAD treatment, we measured estradiol and testosterone levels from plasma and brain aromatase expression in FAD and saline treated dominant males. We found that estradiol levels decreased and testosterone levels increased in response to FAD treatment. Moreover, FAD treated males had increased aromatase expression in the gigantocellular portion of the POA, possibly a compensatory response. Overall, our results suggest aromatase is a key enzyme that promotes aggression in A. burtoni males through actions in the preoptic area. ?? 2013 Elsevier Inc.},
	keywords = {Aggression, Aromatase, Estrogen, Fadrozole, Testosterone},
	isbn = {0031-9384},
	url = {http://dx.doi.org/10.1016/j.physbeh.2013.02.004},
	author = {Huffman, Lin S. and O{\textquoteright}Connell, Lauren A. and Hofmann, Hans A.}
}
@article {7347,
	title = {Female preference for males depends on reproductive physiology in the African cichlid fish Astatotilapia burtoni},
	journal = {General and Comparative Endocrinology},
	volume = {180},
	number = {1},
	year = {2013},
	month = {2013///},
	pages = {56 - 63},
	publisher = {Elsevier Inc.},
	abstract = {Mate choice is fundamental to sexual selection, yet little is known about underlying physiological mechanisms that influence female mating decisions. We investigated the endocrine underpinnings of female mate choice in the African cichlid Astatotilapia burtoni, a non-seasonal breeder. In addition to profiling behavioral and hormonal changes across the female reproductive cycle, we tested two hypotheses regarding possible factors influencing female mate choice. We first asked whether female mate choice is influenced by male visual and/or chemical cues. A. burtoni females were housed for one full reproductive cycle in the center of a dichotomous choice apparatus with a large (attractive) or small (unattractive) conspecific male on either side. Females associated mostly with small, less attractive males, but on the day of spawning reversed their preference to large, attractive males, with whom they mated almost exclusively, although this choice depended on the relative amount of androgens released into the water by small males. We next asked whether male behavior or androgen levels change in relation to the stimulus females{\textquoteright} reproductive state. We found that stimulus male aggression decreased and reproductive displays increased as the day of spawning approached. Moreover male testosterone levels changed throughout the females{\textquoteright} reproductive cycle, with larger males releasing more testosterone into the water than small males. Our data suggest that female association in a dichotomous choice assay is only indicative of the actual mate choice on the day of spawning. Furthermore, we show that male behavior and hormone levels are dependent on the reproductive state of conspecific females. ?? 2012 Elsevier Inc.},
	keywords = {Mate choice, Prostaglandin F2??, Reproductive physiology, Sex steroid hormones, Sexual behavior, Sexual selection},
	url = {http://dx.doi.org/10.1016/j.ygcen.2012.10.014},
	author = {Kidd, Michael R. and O{\textquoteright}Connell, Lauren A. and Kidd, Celeste E. and Chen, Christine W. and Fontenot, Miles R. and Williams, Sidney J. and Hofmann, Hans A.}
}
@article {7348,
	title = {Neurochemical profiling of dopaminergic neurons in the forebrain of a cichlid fish, Astatotilapia burtoni},
	journal = {Journal of Chemical Neuroanatomy},
	volume = {47},
	year = {2013},
	month = {2013///},
	pages = {106 - 115},
	publisher = {Elsevier B.V.},
	abstract = {Across vertebrates, the mesolimbic reward system is a highly conserved neural network that serves to evaluate the salience of environmental stimuli, with dopamine as the neurotransmitter most relevant to its function. Although brain regions in the dopaminergic reward system have been well characterized in mammals, homologizing these brain areas with structures in teleosts has been controversial, especially for the mesencephalo-diencephalic dopaminergic cell populations. Here we examine the neurochemical profile of five dopaminergic cell groups (Vc, POA, PPr, TPp, pTn) in the model cichlid Astatotilapia burtoni to better understand putative homology relationships between teleosts and mammals. We characterized in the adult brain the expression patterns of three genes (etv5, nr4a2, and pitx3) that either specify dopaminergic cell fate or maintain dopaminergic cell populations. We then determined whether these genes are expressed in dopaminergic cells. We find many striking similarities in these gene expression profiles between dopaminergic cell populations in teleosts and their putative mammalian homologs. Our results suggest that many of these dopaminergic cell groups are indeed evolutionarily ancient and conserved across vertebrates. ?? 2013 Elsevier B.V.},
	keywords = {dopamine, Etv5, Nr4a2, Nurr1, Pitx3, Tyrosine hydroxylase, Ventral tegmental area},
	url = {http://dx.doi.org/10.1016/j.jchemneu.2012.12.007},
	author = {O{\textquoteright}Connell, Lauren A. and Fontenot, Miles R. and Hofmann, Hans A.}
}
@article {7382,
	title = {Neuroendocrine Mechanisms Underlying Sensory Integration of Social Signals},
	journal = {Journal of Neuroendocrinology},
	volume = {25},
	number = {7},
	year = {2013},
	month = {2013///},
	pages = {644 - 654},
	abstract = {Individuals integrate information about their environment into adaptive behavioural responses, yet how different sensory modalities contribute to these decisions and where in the brain this integration occurs is not well understood. We presented male cichlid fish (Astatotilapia burtoni) with sensory information in three social contexts: intruder challenge, reproductive opportunity and a socially neutral situation. We then measured behavioural and hormonal responses along with induction of the immediate early gene c-Fos in candidate forebrain regions. In the intruder challenge context, males were exposed to either a visual stimulus of a dominant male, the putative male pheromone androstenedione, or both. We found that, compared to the neutral context, a visual stimulus was necessary and sufficient for an aggressive response, whereas both chemical and visual stimuli were needed for an androgen response. In the reproductive opportunity context, males were exposed to either a visual stimulus of a receptive female, a progesterone metabolite (female pheromone) only, or both. We further found that the visual stimulus is necessary and sufficient for an androgen response in the reproductive opportunity context. In the brain, we observed c-Fos induction in response to a visual challenge stimulus specifically in dopaminergic neurones of area Vc (the central region of the ventral telencephalon), a putative striatal homologue, whereas presentation of a chemical stimulus did not induce c-Fos induction in the intruder challenge context. Our results suggest that different sensory cues are processed in a social context-specific manner as part of adaptive decision-making processes.},
	keywords = {Androgens, androstenedione, c-Fos, challenge response, dopamine, social behaviour},
	isbn = {1365-2826 (Electronic)\r0953-8194 (Linking)},
	author = {O{\textquoteright}Connell, L A and Rigney, M M and Dykstra, D W and Hofmann, H. A.}
}
@article {7349,
	title = {New Frontiers for Organismal Biology},
	journal = {BioScience},
	volume = {63},
	number = {6},
	year = {2013},
	month = {2013///},
	pages = {464 - 471},
	abstract = {Understanding how complex organisms function as integrated units that constantly interact with their environment is a long-standing chal- lenge in biology. To address this challenge, organismal biology reveals general organizing principles of physiological systems and behavior{\textemdash}in particular, in complex multicellular animals. Organismal biology also focuses on the role of individual variability in the evolutionary main- tenance of diversity. To broadly advance these frontiers, cross-compatibility of experimental designs, methodological approaches, and data interpretation pipelines represents a key prerequisite. It is now possible to rapidly and systematically analyze complete genomes to elucidate genetic variation associated with traits and conditions that define individuals, populations, and species. However, genetic variation alone does not explain the varied individual physiology and behavior of complex organisms. We propose that such emergent properties of complex organisms can best be explained through a renewed emphasis on the context and life-history dependence of individual phenotypes to comple- ment genetic data.},
	keywords = {environment interaction, Evolution, gene, individuality, life history, Phenotype},
	url = {http://www.jstor.org/stable/info/10.1525/bio.2013.63.6.8},
	author = {K{\"u}ltz, Dietmar and Clayton, David F and Robinson, Gene E and Albertson, Craig and Carey, Hannah V and Molly, E and Dewar, Ken and Edwards, Scott V and Hofmann, Hans A. and Gross, Louis J and Kingsolver, Joel G}
}
@article {7345,
	title = {Prostaglandin F2alpha facilitates female mating behavior based on male performance},
	journal = {Behavioral Ecology and Sociobiology},
	volume = {67},
	number = {8},
	year = {2013},
	month = {2013///},
	pages = {1307 - 1315},
	abstract = {Hormones play an important role in the regulation of reproductive behavior. Here, we examined the effects of the fatty acid derivative prostaglandin F2{\^I}{\textpm} (PGF2) on female sexual behavior as well as the interaction between PGF2-induced mating behavior with male courtship display in the lek-breeding African cichlid fish, Astatotilapia burtoni. In a two-way choice paradigm, we found that nonreproductive females preferred to associate with smaller, less aggressive males over larger, more aggressive males. However, PGF2-treated females dramatically reversed their preference to larger males. In a second experiment, PGF2 treatment dramatically increased sexual behavior in nonreproductive females as measured by time spent in the bower of the stimulus male, even when the female and the stimulus male were separated by a transparent divider. This effect was even more pronounced when the stimulus males were exposed to the putative female pheromone 17{\^I}{\textpm},20{\^I}{\texttwosuperior}-progesterone (17{\^I}{\textpm},20{\^I}{\texttwosuperior}-P). Under full-contact conditions, only PGF2-treated females visited a stimulus male{\textquoteright}s bower, where they even displayed circling behavior usually only seen during spawning. Interestingly, male performance prior to PGF2 treatment predicted female sexual response. Our study demonstrates the importance of PGF2 in the control of female reproductive behavior in interaction with male performance.},
	keywords = {Astatotilapia burtoni, cichlid, Mate choice, Prostaglandin F2 alpha, Reproductive physiology, Sexual behavior, Sexual selection},
	author = {Kidd, Michael R. and Dijkstra, Peter D. and Alcott, Callison and Lavee, Dagan and Ma, Jacqualine and O{\textquoteright}Connell, Lauren A. and Hofmann, Hans A.}
}
@article {7346,
	title = {Sex differences and similarities in the neuroendocrine regulation of social behavior in an African cichlid fish},
	journal = {Hormones and Behavior},
	volume = {64},
	number = {3},
	year = {2013},
	month = {2013///},
	pages = {468 - 476},
	publisher = {Elsevier Inc.},
	abstract = {An individual{\textquoteright}s position in a social hierarchy profoundly affects behavior and physiology through interactions with community members, yet little is known about how the brain contributes to status differences between and within the social states or sexes. We aimed to determine sex-specific attributes of social status by comparing circulating sex steroid hormones and neural gene expression of sex steroid receptors in dominant and subordinate male and female Astatotilapia burtoni, a highly social African cichlid fish. We found that testosterone and 17??-estradiol levels are higher in males regardless of status and dominant individuals regardless of sex. Progesterone was found to be higher in dominant individuals regardless of sex. Based on pharmacological manipulations in males and females, progesterone appears to be a common mechanism for promoting courtship in dominant individuals. We also examined expression of androgen receptors, estrogen receptor ??, and the progesterone receptor in five brain regions that are important for social behavior. Most of the differences in brain sex steroid receptor expression were due to sex rather than status. Our results suggest that the parvocellular preoptic area is a core region for mediating sex differences through androgen and estrogen receptor expression, whereas the progesterone receptor may mediate sex and status behaviors in the putative homologs of the nucleus accumbens and ventromedial hypothalamus. Overall our results suggest sex differences and similarities in the regulation of social dominance by gonadal hormones and their receptors in the brain. ?? 2013 Elsevier Inc.},
	keywords = {Aggression, Androgen, androgen receptor, Estrogen, estrogen receptor, Progesterone, progesterone receptor, Reproduction, Social Behavior},
	isbn = {1095-6867 (Electronic)\r0018-506X (Linking)},
	url = {http://dx.doi.org/10.1016/j.yhbeh.2013.07.003},
	author = {O{\textquoteright}Connell, Lauren A. and Ding, Julia H. and Hofmann, Hans A.}
}
@article {7351,
	title = {Sex steroid hormones modulate responses to social challenge and opportunity in males of the monogamous convict cichlid, Amatitliana nigrofasciata},
	journal = {General and Comparative Endocrinology},
	volume = {189},
	year = {2013},
	month = {2013///},
	pages = {59 - 65},
	publisher = {Elsevier Inc.},
	abstract = {Steroid hormones play an important role in modulating behavioral responses to various social stimuli. It has been suggested that variation in the hormonal regulation of behavior across species is associated with social organization and/or mating system. In order to further elucidate the interplay of hormones and behavior in social situations, we exposed males of the monogamous convict cichlid Amatitliana nigrofasciata to three social stimuli: gravid female, intruder male, and a nonsocial stimulus. We used a repeated measure design to create behavioral profiles and explore how sex steroid hormones respond to and regulate social behavior. Results show distinct behavioral responses to different social situations, with circulating 11-ketotestosterone increasing in response to social stimuli. Pharmacological manipulations using specific androgen and estrogen receptor agonists and antagonists exposed complex control over digging behavior in the social opportunity context. In the social challenge context, aggressive behaviors decreased in response to blocking the androgen receptor pathway. Our results extend our understanding of sex steroid regulation of behavioral responses to social stimulation. ?? 2013 Elsevier Inc.},
	keywords = {11-Ketotestosterone, Androgen, Estrogen, Reproduction, Social Behavior, Testosterone},
	url = {http://dx.doi.org/10.1016/j.ygcen.2013.04.031},
	author = {Sessa, Anna K and Harris, Rayna M. and Hofmann, Hans A.}
}
@article {7360,
	title = {Androgens coordinate neurotransmitter-related gene expression in male whiptail lizards},
	journal = {Genes, Brain and Behavior},
	volume = {11},
	number = {7},
	year = {2012},
	month = {2012///},
	pages = {813 - 818},
	abstract = {Sex steroid hormones coordinate neurotransmitter systems in the male brain to facilitate sexual behavior. Although neurotransmitter release in the male brain has been well documented, little is known about how androgens orchestrate changes in gene expression of neurotransmitter receptors. We used male whiptail lizards (Cnemidophorus inornatus) to investigate how androgens alter neurotransmitter-related gene expression in brain regions involved in social decision making. We focused on three neurotransmitter systems involved in male-typical sexual behavior, including the N-methyl-d-aspartate (NMDA) glutamate receptor, nitric oxide and dopamine receptors. Here, we show that in androgen-treated males, there are coordinated changes in neurotransmitter-related gene expression. In androgen-implanted castrates compared with blank-implanted castrates (control group), we found associated increases in neuronal nitric oxide synthase gene expression in the nucleus accumbens (NAcc), preoptic area and ventromedial hypothalamus, a decrease of NR1 gene expression (obligate subunit of NMDA receptors) in the medial amygdaloid area and NAcc and a decrease in D1 and D2 dopamine receptor gene expression in the NAcc. Our results support and expand the current model of androgen-mediated gene expression changes of neurotransmitter-related systems that facilitate sexual behavior in males. This also suggests that the proposed evolutionarily ancient reward system that reinforces sexual behavior in amniote vertebrates extends to reptiles.},
	keywords = {Androgens, dopamine receptors, glutamate, neuronal nitric oxide synthase, Sexual behavior},
	isbn = {1601-183X (Electronic)\r1601-183X (Linking)},
	author = {O{\textquoteright}Connell, L A and Mitchell, M M and Hofmann, H. A. and Crews, D}
}
@article {7353,
	title = {Distribution of nonapeptide systems in the forebrain of an African cichlid fish, Astatotilapia burtoni},
	journal = {Journal of Chemical Neuroanatomy},
	volume = {44},
	number = {2},
	year = {2012},
	month = {2012///},
	pages = {86 - 97},
	publisher = {Elsevier B.V.},
	abstract = {Nonapeptides and their receptors have important functions in mediating social behavior across vertebrates. Where these nonapeptides are synthesized in the brain has been studied extensively in most vertebrate lineages, yet we know relatively little about the neural distribution of nonapeptide receptors outside of mammals. As nonapeptides play influential roles in behavioral regulation in all vertebrates, including teleost fish, we mapped the distributions of the receptors for arginine vasotocin (AVT; homolog of arginine vasopressin) and isotocin (IST; homolog of oxytocin/mesotocin) throughout the forebrain of Astatotilapia burtoni, an African cichlid fish with behavioral phenotypes that are plastic and reversible based on the immediate social environment. We characterized the distribution of the AVT V1a2 receptor (V1aR) and the IST receptor (ITR) using both immunohistochemistry for protein detection and in situ hybridization for mRNA detection, as well as AVT and IST using immunohistochemistry. Expression of the neuropeptide receptors was widely distributed throughout the fore- and midbrain, including the proposed teleost homologs of the mammalian amygdala complex, striatum, hypothalamus, and ventral tegmental area. We conclude that although the location of nonapeptide synthesis is restricted compared to tetrapod vertebrates, the distribution of nonapeptide receptors is highly conserved across taxa. Our results significantly extend our knowledge of where nonapeptides act in the brains of teleosts to mediate social transitions and behavior. ?? 2012 Elsevier B.V.},
	keywords = {Arginine vasotocin, Isotocin, Isotocin receptor, Mesolimbic reward system, Social behavior network, V1a receptor},
	isbn = {1873-6300 (Electronic) 0891-0618 (Linking)},
	url = {http://dx.doi.org/10.1016/j.jchemneu.2012.05.002},
	author = {Huffman, Lin S. and O{\textquoteright}Connell, Lauren A. and Kenkel, Carly D. and Kline, Richard J. and Khan, Izhar A. and Hofmann, Hans A.}
}
@article {7359,
	title = {Divergent hormonal responses to social competition in closely related species of haplochromine cichlid fish},
	journal = {Hormones and Behavior},
	volume = {61},
	number = {4},
	year = {2012},
	month = {2012///},
	pages = {518 - 526},
	publisher = {Elsevier Inc.},
	abstract = {The diverse cichlid species flocks of the East African lakes provide a classical example of adaptive radiation. Territorial aggression is thought to influence the evolution of phenotypic diversity in this system. Most vertebrates mount hormonal (androgen, glucocorticoid) responses to a territorial challenge. These hormones, in turn, influence behavior and multiple aspects of physiology and morphology. Examining variation in competition-induced hormone secretion patterns is thus fundamental to an understanding of the mechanisms of phenotypic diversification. We test here the hypothesis that diversification in male aggression has been accompanied by differentiation in steroid hormone levels. We studied two pairs of sibling species from Lake Victoria belonging to the genera Pundamilia and Mbipia. The two genera are ecologically differentiated, while sibling species pairs differ mainly in male color patterns. We found that aggression directed toward conspecific males varied between species and across genera: Pundamilia nyererei males were more aggressive than Pundamilia pundamilia males, and Mbipia mbipi males were more aggressive than Mbipia lutea males. Males of both genera exhibited comparable attack rates during acute exposure to a novel conspecific intruder, while Mbipia males were more aggressive than Pundamilia males during continuous exposure to a conspecific rival, consistent with the genus difference in feeding ecology. Variation in aggressiveness between genera, but not between sibling species, was reflected in androgen levels. We further found that M. mbipi displayed lower levels of cortisol than M. lutea. Our results suggest that concerted divergence in hormones and behavior might play an important role in the rapid speciation of cichlid fishes. ?? 2012 Elsevier Inc.},
	keywords = {11-Ketotestosterone, cichlid, Cortisol, Male-male competition, speciation, steroid, teleost, Testosterone},
	isbn = {1095-6867 (Electronic) 0018-506X (Linking)},
	url = {http://dx.doi.org/10.1016/j.yhbeh.2012.01.011},
	author = {Dijkstra, Peter D. and Verzijden, Machteld N and Groothuis, Ton G G and Hofmann, Hans A.}
}
@article {7354,
	title = {Evolution of a Vertebrate Social Decision-Making Network},
	journal = {Science},
	volume = {336},
	number = {6085},
	year = {2012},
	month = {2012///},
	pages = {1154 - 1157},
	abstract = {Animals evaluate and respond to their social environment with adaptive decisions. Revealing the neural mechanisms of such decisions is a major goal in biology. We analyzed expression profiles for 10 neurochemical genes across 12 brain regions important for decision-making in 88 species representing five vertebrate lineages. We found that behaviorally relevant brain regions are remarkably conserved over 450 million years of evolution. We also find evidence that different brain regions have experienced different selection pressures, because spatial distribution of neuroendocrine ligands are more flexible than their receptors across vertebrates. Our analysis suggests that the diversity of social behavior in vertebrates can be explained, in part, by variations on a theme of conserved neural and gene expression networks.},
	isbn = {1095-9203 (Electronic)\n0036-8075 (Linking)},
	url = {http://www.sciencemag.org/content/336/6085/1154\%5Cnhttp://www.ncbi.nlm.nih.gov/pubmed/22654056\%5Cnhttp://www.sciencemag.org/content/336/6085/1154.full.pdf\%5Cnhttp://www.sciencemag.org/content/336/6085/1154.short},
	author = {O{\textquoteright}Connell, Lauren A and Hofmann, Hans A.}
}
@article {7357,
	title = {Females of an African cichlid fish display male-typical social dominance behavior and elevated androgens in the absence of males},
	journal = {Hormones and Behavior},
	volume = {61},
	number = {4},
	year = {2012},
	month = {2012///},
	pages = {496 - 503},
	publisher = {Elsevier Inc.},
	abstract = {Social environment can affect the expression of sex-typical behavior in both males and females. Males of the African cichlid species Astatotilapia burtoni have long served as a model system to study the neural, endocrine, and molecular basis of socially plastic dominance behavior. Here we show that in all-female communities of A. burtoni, some individuals acquire a male-typical dominance phenotype, including aggressive territorial defense, distinctive color patterns, and courtship behavior. Furthermore, dominant females have higher levels of circulating androgens than either subordinate females or females in mixed-sex communities. These male-typical traits do not involve sex change, nor do the social phenotypes in all-female communities differ in relative ovarian size, suggesting that factors other than gonadal physiology underlie much of the observed variation. In contrast to the well-studied situation in males, dominant and subordinate females do not differ in the rate of somatic growth. Dominant females are not any more likely than subordinates to spawn with an introduced male, although they do so sooner. These results extend the well known extraordinary behavioral plasticity of A. burtoni to the females of this species and provide a foundation for uncovering the neural and molecular basis of social dominance behavior while controlling for factors such as sex, gonadal state and growth. ?? 2012 Elsevier Inc.},
	keywords = {Aggression, Growth, Reproduction, Sex steroid hormones, Social dominance},
	isbn = {1095-6867 (Electronic) 0018-506X (Linking)},
	url = {http://dx.doi.org/10.1016/j.yhbeh.2012.01.006},
	author = {Renn, Suzy C. P. and Fraser, Eleanor J. and Aubin-Horth, Nadia and Trainor, Brian C. and Hofmann, Hans A.}
}
@article {7356,
	title = {Isotocin regulates paternal care in a monogamous cichlid fish},
	journal = {Hormones and Behavior},
	volume = {61},
	number = {5},
	year = {2012},
	month = {2012///},
	pages = {725 - 733},
	publisher = {Elsevier Inc.},
	abstract = {While the survival value of paternal care is well understood, little is known about its physiological basis. Here we investigate the neuroendocrine contributions to paternal care in the monogamous cichlid, Amatitlania nigrofasciata. We first explored the dynamic range of paternal care in three experimental groups: biparental males (control fathers housed with their mate), single fathers (mate removed), or lone males (mate and offspring removed). We found that control males gradually increase paternal care over time, whereas single fathers increased care immediately after mate removal. Males with offspring present had lower levels of circulating 11-ketotestosterone (11-KT) yet still maintained aggressive displays toward brood predators. To determine what brain regions may contribute to paternal care, we quantified induction of the immediate early gene c-Fos, and found that single fathers have more c-Fos induction in the forebrain area Vv (putative lateral septum homologue), but not in the central pallium (area Dc). While overall preoptic area c-Fos induction was similar between groups, we found that parvocellular preoptic isotocin (IST) neurons in single fathers showed increased c-Fos induction, suggesting IST may facilitate the increase of paternal care after mate removal. To functionally test the role of IST in regulating paternal care, we treated biparental males with an IST receptor antagonist, which blocked paternal care. Our results indicate that isotocin plays a significant role in promoting paternal care, and more broadly suggest that the convergent evolution of paternal care across vertebrates may have recruited similar neuroendocrine mechanisms. ?? 2012 Elsevier Inc..},
	keywords = {11-Ketotestosterone, Isotocin, Lateral septum, Paternal care, Preoptic Area, Testosterone},
	isbn = {1095-6867 (Electronic) 0018-506X (Linking)},
	url = {http://dx.doi.org/10.1016/j.yhbeh.2012.03.009},
	author = {O{\textquoteright}Connell, Lauren A. and Matthews, Bryan J. and Hofmann, Hans A.}
}
@article {7355,
	title = {Repeated parallel evolution of parental care strategies within xenotilapia, a genus of cichlid fishes from Lake Tanganyika},
	journal = {PLoS ONE},
	volume = {7},
	number = {2},
	year = {2012},
	month = {2012///},
	abstract = {The factors promoting the evolution of parental care strategies have been extensively studied in experiment and theory. However, most attempts to examine parental care in an evolutionary context have evaluated broad taxonomic categories. The explosive and recent diversifications of East African cichlid fishes offer exceptional opportunities to study the evolution of various life history traits based on species-level phylogenies. The Xenotilapia lineage within the endemic Lake Tanganyika cichlid tribe Ectodini comprises species that display either biparental or maternal only brood care and hence offers a unique opportunity to study the evolution of distinct parental care strategies in a phylogenetic framework. In order to reconstruct the evolutionary relationships among 16 species of this lineage we scored 2,478 Amplified Fragment Length Polymorphisms (AFLPs) across the genome. We find that the Ectodini genus Enantiopus is embedded within the genus Xenotilapia and that during 2.5 to 3 million years of evolution within the Xenotilapia clade there have been 3-5 transitions from maternal only to biparental care. While most previous models suggest that uniparental care (maternal or paternal) arose from biparental care, we conclude from our species-level analysis that the evolution of parental care strategies is not only remarkably fast, but much more labile than previously expected.},
	isbn = {1932-6203 (Electronic)\n1932-6203 (Linking)},
	author = {Kidd, Michael R. and Duftner, Nina and Koblm{\"u}ller, Stephan and Sturmbauer, Christian and Hofmann, Hans A.}
}
@article {7361,
	title = {Rising StARs: Behavioral, hormonal, and molecular responses to social challenge and opportunity},
	journal = {Hormones and Behavior},
	volume = {61},
	number = {4},
	year = {2012},
	month = {2012///},
	pages = {631 - 641},
	publisher = {Elsevier Inc.},
	abstract = {Across taxa, individuals must respond to a dynamic social environment of challenges and opportunities on multiple biological levels, including behavior, hormone profiles, and gene expression. We investigated the response to a complex social environment including both territorial challenges and reproductive opportunities in the African cichlid fish Astatotilapia burtoni (Burton{\textquoteright}s mouthbrooder), a species well-known for its phenotypic plasticity. Male A. burtoni are either socially dominant or subordinate and can transition between the two phenotypes. We used this transition to simultaneously study changes in aggression, reproductive behavior, testosterone and estradiol levels, gonadal histology, and testes expression of three genes involved in testosterone synthesis. We have found that males immediately become aggressive and increase testosterone levels when they become dominant in this paradigm of challenge and opportunity. Reproductive behavior and estradiol increase slightly later but are also up-regulated within 24. h. Increases in steroid hormone levels are accompanied by an increase in expression of steroidogenic acute regulatory protein (StAR), the rate-limiting enzyme during testosterone synthesis, as well as an increase in testis maturation as measured by histological organization. Reproductive behavior was found to correlate with female gravidity, suggesting that males were able to perceive reproductive opportunity. Our study demonstrates the rapid plasticity at multiple levels of biological organization that animals can display in response to changes in their complex social environment. ?? 2012 Elsevier Inc.},
	keywords = {Aggression, Androgen, Aromatase, Gene Expression, Luteinizing hormone receptor, Plasticity, Sex steroid hormone, Sexual behavior, Social dominance},
	isbn = {1095-6867 (Electronic) 0018-506X (Linking)},
	url = {http://dx.doi.org/10.1016/j.yhbeh.2012.02.016},
	author = {Huffman, Lin S. and Mitchell, Maggie M and O{\textquoteright}Connell, Lauren A. and Hofmann, Hans A.}
}
@article {7352,
	title = {Social context influences aggressive and courtship behavior in a cichlid fish},
	journal = {PLoS ONE},
	volume = {7},
	number = {7},
	year = {2012},
	month = {2012///},
	abstract = {Social interactions require knowledge of the environment and status of others, which can be acquired indirectly by observing the behavior of others. When being observed, animals can also alter their signals based on who is watching. Here we observed how male cichlid fish (Astatotilapia burtoni) behave when being watched in two different contexts. In the first, we show that aggressive and courtship behaviors displayed by subordinate males depends critically on whether dominant males can see them, and in the second, we manipulated who was watching aggressive interactions and showed that dominant males will change their behavior depending on audience composition. In both cases, when a more dominant individual is out of view and the audience consists of more subordinate individuals, those males signal key social information to females by displaying courtship and dominant behaviors. In contrast, when a dominant male is present, males cease both aggression and courtship. These data suggest that males are keenly aware of their social environment and modulate their aggressive and courtship behaviors strategically for reproductive and social advantage.},
	isbn = {1932-6203 (Electronic)\r1932-6203 (Linking)},
	author = {Desjardins, Julie K. and Hofmann, Hans A. and Fernald, Russell D.}
}
@article {7358,
	title = {Social status predicts how sex steroid receptors regulate complex behavior across levels of biological organization},
	journal = {Endocrinology},
	volume = {153},
	number = {3},
	year = {2012},
	month = {2012///},
	pages = {1341 - 1351},
	abstract = {Social status strongly affects behavior and physiology, in part mediated by gonadal hormones, although how each sex steroid acts across levels of biological organization is not well understood. We examine the role of sex steroids in modulating social behavior in dominant (DOM) and subordinate (SUB) males of a highly social fish, Astatotilapia burtoni. We first used agonists and antagonists to each sex steroid receptor and found that androgens and progestins modulate courtship behavior only in DOM, whereas estrogens modulate aggressive behavior independent of social status. We then examined the hormonal and physiological responses to sex steroid receptor antagonist treatment and uncovered substantial changes in circulating steroid hormone levels and gonad size only in SUB, not in DOM. Consistent with status-based physiological sensitivities to drug manipulation, we found that neuropeptide and steroid receptor gene expression in the preoptic area was sensitive only in SUB. However, when we compared the transcriptomes of males that received either vehicle or an estrogen receptor antagonist, 8.25\% of all genes examined changed expression in DOM in comparison with only 0.56\% in SUB. Finally, we integrate behavior, physiology, and brain gene expression to infer functional modules that underlie steroid receptor regulation of behavior. Our work suggests that environmentally induced changes at one level of biological organization do not simply affect changes of similar magnitude at other levels, but that instead very few key pathways likely serve as conduits for executing plastic responses across multiple levels.},
	isbn = {1945-7170 (Electronic)\n0013-7227 (Linking)},
	author = {O{\textquoteright}Connell, Lauren A. and Hofmann, Hans A.}
}
@article {7362,
	title = {{\textquoteright}Winner effect{\textquoteright} without winning: Unresolved social conflicts increase the probability of winning a subsequent contest in a cichlid fish},
	journal = {Physiology and Behavior},
	volume = {105},
	number = {2},
	year = {2012},
	month = {2012///},
	pages = {489 - 492},
	publisher = {Elsevier Inc.},
	abstract = {Previous winning experience increases the probability of winning a subsequent contest. However, it is not clear whether winning probability is affected only by the outcome of the contest (winning or losing) or whether fighting experience itself is also sufficient to induce this effect. We investigated this question in the East African cichlid fish Pundamilia spec. To create an unresolved conflict we allowed males to fight their own mirror image prior to a real fight against a size-matched non-mirror-stimulated control male. When males fight their own mirror image, the image{\textquoteright}s response corresponds to the action of the focal animal, creating symmetrical fighting conditions without the experience of losing or winning. We found that mirror-stimulated males were more likely to win an ensuing contest than control males. Interestingly, in this species mirror stimulation also induced an increase in circulating androgens, which is consistent with the hypothesis that stimulation of these sex steroids during aggressive encounters may prepare the animal for subsequent encounters. Our results suggest that fighting experience alone coupled with an androgen response, increases the likelihood of winning, even in the absence of a winning experience. ?? 2011 Elsevier Inc.},
	keywords = {Aggression, Androgens, Challenge hypothesis, cichlid, Winner effect},
	isbn = {1873-507X (Electronic) 0031-9384 (Linking)},
	url = {http://dx.doi.org/10.1016/j.physbeh.2011.08.029},
	author = {Dijkstra, Peter D. and Schaafsma, Sara M. and Hofmann, Hans A. and Groothuis, Ton G G}
}
@article {7326,
	title = {Characterization of the dopamine system in the brain of the tungara frog, Physalaemus pustulosus},
	journal = {Brain, Behavior and Evolution},
	volume = {76},
	number = {3-4},
	year = {2011},
	month = {2011///},
	pages = {211 - 225},
	abstract = {Dopamine is an evolutionarily ancient neurotransmitter that plays an essential role in mediating behavior. In vertebrates, dopamine is central to the mesolimbic reward system, a neural network concerned with the valuation of stimulus salience, and to the nigrostriatal motor system and hypothalamic nuclei involved in the regulation of locomotion and social behavior. In amphibians, dopaminergic neurons have been mapped out in several species, yet the distribution of dopaminoreceptive cells is unknown. The t{\'u}ngara frog, Physalaemus pustulosus, is an excellent model system for the study of neural mechanisms by which valuations of stimuli salience and social decisions are made, especially in the context of mate choice. In order to better understand where dopamine acts to regulate social decisions in this species, we have determined the distribution of putative dopaminergic cells (using tyrosine hydroxylase immunohistochemistry) and cells receptive to dopaminergic signaling (using DARPP-32 immunohistochemistry) throughout the brain of P. pustulosus. The distribution of dopaminergic cells was comparable to other anurans. DARPP-32 immunoreactivity was identified in key brain regions known to modulate social behavior in other vertebrates including the proposed anuran homologues of the mammalian amygdalar complex, nucleus accumbens, hippocampus, striatum, preoptic area, anterior hypothalamus, ventromedial hypothalamus, and ventral tegmental area/substantia nigra pars compacta. Due to its widespread distribution, DARPP-32 likely also plays many roles in non-limbic brain regions that mediate non-social information processing. These results significantly extend our understanding of the distribution of the dopaminergic system in the anuran brain and beyond.},
	keywords = {DARPP-32, Dopamine receptor, Mate choice, Mesolimbic reward system, Posterior tuberculum, Tyrosine hydroxylase},
	isbn = {1421-9743 (Electronic) 0006-8977 (Linking)},
	author = {O{\textquoteright}Connell, Lauren A. and Matthews, Bryan J. and Ryan, Michael J. and Hofmann, Hans A.}
}
@article {7328,
	title = {Characterization of the dopaminergic system in the brain of an African cichlid fish, Astatotilapia burtoni},
	journal = {Journal of Comparative Neurology},
	volume = {519},
	number = {1},
	year = {2011},
	month = {2011///},
	pages = {75 - 92},
	abstract = {Catecholamines, such as dopamine, are evolutionarily ancient neurotransmitters that play an essential role in mediating behavior. In vertebrates, dopamine is central to the nigrostriatal motor and mesolimbic reward systems. Despite its importance, the distribution of the dopaminergic system has not been well studied in the teleost brain. The African cichlid fish Astatotilapia burtoni has become an important model system in social neuroscience and lends itself to uncovering how social decisions are implemented in the brain. To understand better where dopamine acts to regulate social behavior in this species, we have determined the distribution of putative dopaminergic cells and fibers (by tyrosine hydroxylase immunohistochemistry) and dopamine receptors (by in situ hybridization for the D(1A) and D(2) dopamine receptor subtypes) throughout the forebrain and part of the mesencephalon of A. burtoni. Tyrosine hydroxylase immunoreactivity was evident in several regions of the fore- and midbrain, in support of putative homologies to tetrapods. Additionally, the D(1A) and D(2) receptors were identified in brain regions known to modulate social behavior in other vertebrates, including the proposed teleost homologues of the mammalian amygdalar complex, hippocampus, striatum, preoptic area, anterior hypothalamus, ventromedial hypothalamus, and ventral tegmental area/substantia nigra pars compacta. Tyrosine hydroxylase-immunoreactive fibers as well as D(1A) and D(2) receptor expression overlap almost completely in their distribution. These results significantly extend our understanding of the distribution of the dopaminergic system in the teleost brain and suggest a conserved role of dopamine in modulating behavior across vertebrates.},
	keywords = {D1A, D2, hypothalamus, Indexing terms: dopamine receptor, Posterior tuberculum, Reward system, Social Behavior, Tyrosine hydroxylase},
	isbn = {1096-9861 (Electronic) 0021-9967 (Linking)},
	author = {O{\textquoteright}Connell, Lauren A. and Fontenot, Miles R. and Hofmann, Hans A.}
}
@article {7364,
	title = {The distribution of an avt v1a receptor in the brain of a sex changing fish, epinephelus adscensionis},
	journal = {Journal of Chemical Neuroanatomy},
	volume = {42},
	number = {1},
	year = {2011},
	month = {2011///},
	pages = {72 - 88},
	abstract = {The present study describes the distribution of an arginine vasotocin (AVT) V1a receptor (AVTr) throughout the brain of a sex-changing grouper, rock hind Epinephelus adscensionis. The objectives of this study were to describe the AVTr distribution in the brain of rock hind for potential linkages of the AVT hormone system with sex-specific behaviors observed in this species and to examine sex-specific differences that might exist. An antibody was designed for rock hind AVTr against the deduced amino acid sequence for the third intracellular loop. Protein expression, identified with immunohistochemistry showed high concordance with mRNA expression, identified with in situ hybridization. AVTr protein and mRNA expression was widely distributed throughout the brain, indicating that AVT may act as a neuromodulator via this V1a receptor subtype. AVTr protein and mRNA were present in regions associated with behavior, reproduction and spatial learning, as well as sensory functions such as vision, olfaction and lateral line sensory processing. We observed high AVTr expression in granular cell formations in the internal cellular layer of olfactory bulbs, torus longitudinalis, granular layer of the corpus cerebellum, valvula of the cerebellum, nuclei of the lateral and posterior recesses, and granular eminence. High protein and mRNA expression was also observed in the preoptic area, anterior hypothalamus, and habenular nucleus. No obvious sex differences were noted in any region of the rock hind brain. ?? 2011 Elsevier B.V.},
	keywords = {Hermaphroditism, Immunohistochemistry, In Situ Hybridization, Rock hind, Social Behavior, Vasotocin receptor},
	isbn = {1873-6300 (Electronic) 0891-0618 (Linking)},
	author = {Kline, Richard J. and O{\textquoteright}Connell, Lauren A. and Hofmann, Hans A. and Holt, G. Joan and Khan, Izhar A.}
}
@article {7327,
	title = {Genes, hormones, and circuits: An integrative approach to study the evolution of social behavior},
	journal = {Frontiers in Neuroendocrinology},
	volume = {32},
	number = {3},
	year = {2011},
	month = {2011///},
	pages = {320 - 335},
	abstract = {Tremendous progress has been made in our understanding of the ultimate and proximate mechanisms underlying social behavior, yet an integrative evolutionary analysis of its underpinnings has been difficult. In this review, we propose that modern genomic approaches can facilitate such studies by integrating four approaches to brain and behavior studies: (1) animals face many challenges and opportunities that are ecologically and socially equivalent across species; (2) they respond with species-specific, yet quantifiable and comparable approach and avoidance behaviors; (3) these behaviors in turn are regulated by gene modules and neurochemical codes; and (4) these behaviors are governed by brain circuits such as the mesolimbic reward system and the social behavior network. For each approach, we discuss genomic and other studies that have shed light on various aspects of social behavior and its underpinnings and suggest promising avenues for future research into the evolution of neuroethological systems. ?? 2010 Elsevier Inc.},
	keywords = {Approach, Avoidance, challenge response, Decision-making, Developmental system drift, Evolution, Genomics, Mesolimbic reward system, Phenologs, Social behavior network},
	isbn = {1095-6808 (Electronic) 0091-3022 (Linking)},
	author = {O{\textquoteright}Connell, Lauren A. and Hofmann, Hans A.}
}
@article {7325,
	title = {Neural distribution of the nuclear progesterone receptor in the tungara frog, Physalaemus pustulosus},
	journal = {Journal of Chemical Neuroanatomy},
	volume = {41},
	number = {3},
	year = {2011},
	month = {2011///},
	pages = {137 - 147},
	publisher = {Elsevier B.V.},
	abstract = {The gonadal steroid hormone progesterone plays an important role across all vertebrates in mediating female reproductive physiology and behavior. Many effects of progesterone are mediated by a nuclear progesterone receptor (PR), which is crucial for integration of external signals and internal physiological cues in the brain to produce an appropriate behavioral output. The t??ngara frog, Physalaemus pustulosus, is an excellent model system for the study of mechanisms by which sensory signals, such as auditory communication, are processed within neural circuits where mate choice decisions are made. To establish a framework for studying the neural basis of mate choice and social behavior in this species, we first describe the cytoarchitecture of the brain using Nissl-stained sections. Then, in order to better understand where progesterone acts to regulate social decisions, we determined the distribution of PR protein throughout the brain of P. pustulosus by immunohistochemistry. We found PR immunoreactivity in key brain regions known to modulate the processing of auditory cues and social behavior in other vertebrates. Due to its widespread distribution, PR likely also plays important roles in non-limbic brain regions that mediate non-social information processing. Further, we have colocalized PR with tyrosine hydroxylase, providing a functional context for the role of progesterone in mediating motivation and motor behavior. Our results significantly extend our understanding of hormonal modulation in the anuran brain and support the important role of the nuclear progesterone receptor in modulating female mate choice and receptivity in amphibians and across vertebrates. ?? 2011 Elsevier B.V.},
	keywords = {Amphibian, Cytoarchitecture, Mate choice, Neuroanatomy, progesterone receptor, Tyrosine hydroxylase},
	isbn = {1873-6300 (Electronic)\r0891-0618 (Linking)},
	url = {http://dx.doi.org/10.1016/j.jchemneu.2011.01.002},
	author = {O{\textquoteright}Connell, Lauren A. and Ding, Julia H. and Ryan, Michael J. and Hofmann, Hans A.}
}
@article {7330,
	title = {Neuropeptide regulation of social behavior in a monogamous cichlid fish},
	journal = {Physiology and Behavior},
	volume = {102},
	number = {3-4},
	year = {2011},
	month = {2011///},
	pages = {296 - 303},
	abstract = {The nonapeptides arginine vasopressin (AVP; including its non-mammalian homolog arginine vasotocin, AVT) and oxytocin (OT; including its non-mammalian homologs mesotocin, MT, and isotocin, IT) regulate social behavior, including aggression and reproduction, via receptors conserved across vertebrates. In monogamous prairie voles, the vasopressin and oxytocin pathways are crucially important for pair-bond formation, specifically by influencing affiliative behavior toward the mate and aggression toward non-mates. Monogamous social systems are found in diverse taxa. We hypothesized that the AVT/IT pathways are associated with mating behavior in monogamous teleost fishes. We used the monogamous convict cichlid, Amatitlania nigrofasciata, to test this idea. In the first experiment, we treated males with a general nonapeptide receptor antagonist during pair-bond formation. Control males were treated with vehicle. On the first day of treatment we observed a significant reduction in both affiliative behavior toward the potential mate and aggression toward neighbors. However, the antagonist did not prevent the pair-bond from forming and the behavioral effects disappeared on subsequent treatment days. In the second experiment, we administered on three consecutive days the AVP/OT receptor antagonist to males that were in an established pair-bond. In established pairs, male affiliation towards the mate and aggressive behavior towards territorial neighbors were not affected by the antagonist. Our results indicate that the basic social behaviors typically mediated by the AVP/OT pathways may provide the building blocks necessary for monogamous mating behavior. ?? 2010 Elsevier Inc.},
	keywords = {Aggression, Amatitlania nigrofasciata, Courtship, Isotocin, Oxytocin, Reproduction, Vasotocin},
	isbn = {1873-507X (Electronic) 0031-9384 (Linking)},
	author = {Oldfield, Ronald G. and Hofmann, Hans A.}
}
@article {7331,
	title = {The role of physiology in the divergence of two incipient cichlid species},
	journal = {Journal of Evolutionary Biology},
	volume = {24},
	number = {12},
	year = {2011},
	month = {2011///},
	pages = {2639 - 2652},
	abstract = {Sexual selection on male coloration has been implicated in the evolution of colourful species flocks of East African cichlid fish. During adaptive radiations, animals diverge in multiple phenotypic traits, but the role of physiology has received limited attention. Here, we report how divergence in physiology may contribute to the stable coexistence of two hybridizing incipient species of cichlid fish from Lake Victoria. Males of Pundamilia nyererei (males are red) tend to defeat those of Pundamilia pundamilia (males are blue), yet the two sibling species coexist in nature. It has been suggested that red males bear a physiological cost that might offset their dominance advantage. We tested the hypothesis that the two species differ in oxidative stress levels and immune function and that this difference is correlated with differences in circulating steroid levels. We manipulated the social context and found red males experienced significantly higher oxidative stress levels than blue males, but only in a territorial context when colour and aggression are maximally expressed. Red males exhibited greater aggression levels and lower humoral immune response than blue males, but no detectable difference in steroid levels. Red males appear to trade off increased aggressiveness with physiological costs, contributing to the coexistence of the two species. Correlated divergence in colour, behaviour and physiology might be widespread in the dramatically diverse cichlid radiations in East African lakes and may play a crucial role in the remarkably rapid speciation of these fish.},
	keywords = {11-Ketotestosterone, Carotenoids, cichlid, immune function, Male-male competition, Oxidative Stress, steroid, teleost, Testosterone},
	isbn = {1420-9101 (Electronic)\r1010-061X (Linking)},
	author = {Dijkstra, P D and Wiegertjes, G F and Forlenza, M and van der Sluijs, I and Hofmann, H. A. and Metcalfe, N B and Groothuis, T G G}
}
@article {7363,
	title = {Serotonergic modulation of startle-escape plasticity in an African cichlid fish: a single-cell molecular and physiological analysis of a vital neural circuit.},
	journal = {Journal of neurophysiology},
	volume = {106},
	number = {1},
	year = {2011},
	month = {2011///},
	pages = {127 - 137},
	abstract = {Social life affects brain function at all levels, including gene expression, neurochemical balance, and neural circuits. We have previously shown that in the cichlid fish Astatotilapia burtoni brightly colored, socially dominant (DOM) males face a trade-off between reproductive opportunities and increased predation risk. Compared with camouflaged subordinate (SUB) males, DOMs exposed to a loud sound pip display higher startle responsiveness and increased excitability of the Mauthner cell (M-cell) circuit that governs this behavior. Using behavioral tests, intracellular recordings, and single-cell molecular analysis, we show here that serotonin (5-HT) modulates this socially regulated plasticity via the 5-HT receptor subtype 2 (5-HTR(2)). Specifically, SUBs display increased sensitivity to pharmacological manipulation of 5-HTR(2) compared with DOMs in both startle-escape behavior and electrophysiological properties of the M-cell. Immunohistochemistry showed serotonergic varicosities around the M-cells, further suggesting that 5-HT impinges directly onto the startle-escape circuitry. To determine whether the effects of 5-HTR(2) are pre- or postsynaptic, and whether other 5-HTR subtypes are involved, we harvested the mRNA from single M-cells via cytoplasmic aspiration and found that 5-HTR subtypes 5A and 6 are expressed in the M-cell. 5-HTR(2), however, was absent, suggesting that it affects M-cell excitability through a presynaptic mechanism. These results are consistent with a role for 5-HT in modulating startle plasticity and increase our understanding of the neural and molecular basis of a trade-off between reproduction and predation.},
	isbn = {1522-1598 (Electronic) 0022-3077 (Linking)},
	author = {Whitaker, K W and Neumeister, H and Huffman, L S and Kidd, C E and Preuss, T and Hofmann, H. A.}
}
@article {7329,
	title = {The Vertebrate mesolimbic reward system and social behavior network: A comparative synthesis},
	journal = {Journal of Comparative Neurology},
	volume = {519},
	number = {18},
	year = {2011},
	month = {2011///},
	pages = {3599 - 3639},
	abstract = {All animals evaluate the salience of external stimuli and integrate them with internal physiological information into adaptive behavior. Natural and sexual selection impinge on these processes, yet our understanding of behavioral decision-making mechanisms and their evolution is still very limited. Insights from mammals indicate that two neural circuits are of crucial importance in this context: the social behavior network and the mesolimbic reward system. Here we review evidence from neurochemical, tract-tracing, developmental, and functional lesion/stimulation studies that delineates homology relationships for most of the nodes of these two circuits across the five major vertebrate lineages: mammals, birds, reptiles, amphibians, and teleost fish. We provide for the first time a comprehensive comparative analysis of the two neural circuits and conclude that they were already present in early vertebrates. We also propose that these circuits form a larger social decision-making (SDM) network that regulates adaptive behavior. Our synthesis thus provides an important foundation for understanding the evolution of the neural mechanisms underlying reward processing and behavioral regulation. J. Comp. Neurol. 519:3599{\textendash}3639, 2011. {\textcopyright} 2011 Wiley-Liss, Inc.},
	keywords = {Amphibian, bird, comparative neuroanatomy, limbic system, neural circuits, reptile, Reward system, Social Behavior, Social behavior network, teleost},
	isbn = {1096-9861 (Electronic)\r0021-9967 (Linking)},
	author = {O{\textquoteright}Connell, Lauren A. and Hofmann, Hans A.}
}
@article {7332,
	title = {Behavioural Genomics : An Organismic Perspective},
	journal = {Encyclopedia of Life science},
	year = {2010},
	month = {2010///},
	pages = {1 - 9},
	abstract = {The behavioural patterns observed in many organisms generally resultfromthe integration ofbothexternaland internal cues. Why do animals behave the way they do? The study of the proximate and ultimate mechanisms underlying animal behaviour tries to answer this ques- tion. Although various approaches have been developed for examining {\textendash} often quantitatively and with increasing specificity and resolution {\textendash} the roles genes play in the regulation of behaviour, until recently they were limited to individual candidate genes and often neglected ultim- ate mechanisms. Advances in genomic approaches in recent years have made it possible to examine gene expression patterns (in the brain and elsewhere) on a genomicscale even in nontraditional, yet ecologicallyand evolutionarily important model systems. As behavioural genomics begins to integrate proximate and ultimate mechanisms of animal behaviour, we may finally under- stand why animals behave the way they do.},
	isbn = {9780470015902},
	author = {Wong, Ryan Y and Hoffmann, Hans a}
}
@article {7341,
	title = {Distribution of sex steroid hormone receptors in the brain of an african cichlid fish, astatotilapia burtoni},
	journal = {Journal of Comparative Neurology},
	volume = {518},
	number = {16},
	year = {2010},
	month = {2010///},
	pages = {3302 - 3326},
	keywords = {androgen receptor, estrogen receptor, hypothalamus, Mesolimbic reward system, progesterone receptor, Social behavior network},
	author = {Munchrath, Lauren A. and Hofmann, Hans A.}
}
@article {7334,
	title = {Early developmental patterning sets the stage for brain evolution.},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {107},
	number = {22},
	year = {2010},
	month = {2010///},
	pages = {9919 - 9920},
	isbn = {1091-6490 (Electronic)\r0027-8424 (Linking)},
	author = {Hofmann, Hans A.}
}
@article {7338,
	title = {Measuring multiple hormones from a single water sample using enzyme immunoassays},
	journal = {General and Comparative Endocrinology},
	volume = {165},
	number = {2},
	year = {2010},
	month = {2010///},
	pages = {277 - 285},
	publisher = {Elsevier Inc.},
	abstract = {Many aquatic species, such as teleosts, release into the water and detect multiple bioactive substances to assist in schooling, migration, alarm reactions, and to stimulate behavioral and physiological responses during reproduction and in parent-offspring interactions. Understanding the complex relationship between hormones, behavior and their function in communication requires the simultaneous examination of multiple circulating hormones. However, repeated blood sampling within a short time period is not possible in smaller animals without impacting the very behaviors under investigation. The non-invasive technique of collecting and measuring hormone values in holding water using either radioimmunoassay (RIA) or enzyme immunoassay (EIA) is becoming widely used in teleost research. Commercial assay kits in particular enable rapid and reliable data generation, yet their assay buffers are often specific and potentially incompatible with each other, which can hinder measuring multiple hormones from the same sample. We present here the validation and application of a "nested" elution technique we developed that allows for repeated sampling of multiple reproductive hormones - testosterone (T), 17??-estradiol (E2), progesterone (P), prostaglandin F2?? (PGF) and 11-ketotestosterone (11KT) - from individual samples of animal holding water by using commercial EIA systems. Our results show that when using appropriate controls to account for possible technical and biological confounds, this technique provides a powerful new tool for research in aquatic endocrinology and physiology. ?? 2009 Elsevier Inc. All rights reserved.},
	keywords = {11-Ketotestosterone, 17??-Estradiol, Astatotilapia burtoni, cichlid, EIA, Environmental toxicology, Enzyme immunoassay, invertebrate, Progesterone, Prostaglandin F2??, steroid, teleost, Testosterone},
	isbn = {1095-6840 (Electronic)\n0016-6480 (Linking)},
	url = {http://dx.doi.org/10.1016/j.ygcen.2009.07.008},
	author = {Kidd, Celeste E. and Kidd, Michael R. and Hofmann, Hans A.}
}
@article {7337,
	title = {The neuroendocrine action potential. Winner of the 2008 Frank Beach Award in Behavioral Neuroendocrinology},
	journal = {Hormones and Behavior},
	volume = {58},
	number = {4},
	year = {2010},
	month = {2010///},
	pages = {555 - 562},
	publisher = {Elsevier Inc.},
	abstract = {Animals are remarkably well equipped to respond to changes in their environment across different time scales and levels of biological organization. Here, I introduce a novel perspective that incorporates the three main processes the nervous system uses to integrate and process information: electrophysiological, genomic, and neuroendocrine action potentials. After discussing several examples of neuroendocrine action potentials, I lay out the commonalities of these temporally organized responses and how they might be interrelated with electrophysiological activity and genomic responses. This framework provides a novel outlook on longstanding questions in behavioral neuroendocrinology and suggests exciting new avenues for further research that will integrate across disciplines and levels of biological organization. ?? 2010 Elsevier Inc.},
	keywords = {Ejaculation, Genomics, Hormones, Immediate early gene, Photostimulated, Refractory period, Reproduction, Seasonality, Sexual selection, Social Behavior},
	isbn = {0018-506X},
	url = {http://dx.doi.org/10.1016/j.yhbeh.2010.06.012},
	author = {Hofmann, Hans A.}
}
@article {7339,
	title = {Parallel Evolution of opsin gene expression in African cichlid fishes},
	journal = {Molecular Biology and Evolution},
	volume = {27},
	number = {12},
	year = {2010},
	month = {2010///},
	pages = {2839 - 2854},
	abstract = {Phenotypic evolution may occur either through alterations to the structure of protein-coding genes or their expression. Evidence for which of these two mechanisms more commonly contribute to the evolution of a phenotype can be garnered from examples of parallel and convergent evolution. The visual system of East African cichlid fishes is an excellent system with which to address this question. Cichlid fishes from Lakes Malawi (LM) and Victoria together exhibit three diverse palettes of coexpressed opsins and several important protein-coding mutations that both shift spectral sensitivity. Here we assess both opsin expression and protein-coding diversity among cichlids from a third rift lake, Lake Tanganyika (LT). We found that Tanganyikan cichlids exhibit three palettes of coexpressed opsins that largely overlap the short-, middle-, and long-wavelength-sensitive palettes of LM cichlids. Bayesian phenotypic clustering and ancestral state reconstructions both support the parallel evolution of the short- and middle-wavelength palettes among cichlids from LT and LM. In each case, these transitions occurred from different ancestors that expressed the same long-wavelength palette. We also identified similar but distinct patterns of correlated evolution between opsin expression, diet, and lens transmittance among cichlids from LT and LM as well. In contrast to regulatory changes, we identified few functional or potentially functional mutations in the protein-coding sequences of three variable opsins, with the possible exception of the SWS1 (ultraviolet) opsin. These results underscore the important contribution that gene regulation can make to rapid phenotypic evolution and adaptation.},
	keywords = {Cichlids, opsin, parallel evolution},
	isbn = {0737-4038\n1537-1719},
	author = {O{\textquoteright}Quin, Kelly E. and Hofmann, Christopher M. and Hofmann, Hans A. and Carleton, Karen L.}
}
@article {7336,
	title = {Paternally induced transgenerational environmental reprogramming of metabolic gene expression in mammals},
	journal = {Cell},
	volume = {143},
	number = {7},
	year = {2010},
	month = {2010///},
	pages = {1084 - 1096},
	publisher = {Elsevier Inc.},
	abstract = {Epigenetic information can be inherited through the mammalian germline and represents a plausible transgenerational carrier of environmental information. To test whether transgenerational inheritance of environmental information occurs in mammals, we carried out an expression profiling screen for genes in mice that responded to paternal diet. Offspring of males fed a low-protein diet exhibited elevated hepatic expression of many genes involved in lipid and cholesterol biosynthesis and decreased levels of cholesterol esters, relative to the offspring of males fed a control diet. Epigenomic profiling of offspring livers revealed numerous modest (\~{}20\%) changes in cytosine methylation depending on paternal diet, including reproducible changes in methylation over a likely enhancer for the key lipid regulator Ppara. These results, in conjunction with recent human epidemiological data, indicate that parental diet can affect cholesterol and lipid metabolism in offspring and define a model system to study environmental reprogramming of the heritable epigenome. {\textcopyright} 2010 Elsevier Inc.},
	isbn = {1097-4172 (Electronic)\n0092-8674 (Linking)},
	url = {http://dx.doi.org/10.1016/j.cell.2010.12.008},
	author = {Carone, Benjamin R. and Fauquier, Lucas and Habib, Naomi and Shea, Jeremy M. and Hart, Caroline E. and Li, Ruowang and Bock, Christoph and Li, Chengjian and Gu, Hongcang and Zamore, Phillip D. and Meissner, Alexander and Weng, Zhiping and Hofmann, Hans A. and Friedman, Nir and Rando, Oliver J.}
}
@article {7340,
	title = {Social and ecological regulation of a decision-making circuit.},
	journal = {Journal of neurophysiology},
	volume = {104},
	number = {October 2010},
	year = {2010},
	month = {2010///},
	pages = {3180 - 3188},
	abstract = {Ecological context, sensory inputs, and the internal physiological state are all factors that need to be integrated for an animal to make appropriate behavioral decisions. However, these factors have rarely been studied in the same system. In the African cichlid fish Astatotilapia burtoni, males alternate between two phenotypes based on position in a social hierarchy. When dominant (DOM), fish display bright body coloration and a wealth of aggressive and reproductive behavioral patterns that make them conspicuous to predators. Subordinate (SUB) males, on the other hand, decrease predation risk by adopting cryptic coloration and schooling behavior. We therefore hypothesized that DOMs would show enhanced startle-escape responsiveness to compensate for their increased predation risk. Indeed, behavioral responses to sound clicks of various intensities showed a significantly higher mean startle rate in DOMs compared with SUBs. Electrophysiological recordings from the Mauthner cells (M-cells), the neurons triggering startle, were performed in anesthetized animals and showed larger synaptic responses to sound clicks in DOMs, consistent with the behavioral results. In addition, the inhibitory drive mediated by interneurons (passive hyperpolarizing potential [PHP] cells) presynaptic to the M-cell was significantly reduced in DOMs. Taken together, the results suggest that the likelihood for an escape to occur for a given auditory stimulus is higher in DOMs because of a more excitable M-cell. More broadly, this study provides an integrative explanation of an ecological and social trade-off at the level of an identifiable decision-making neural circuit.},
	isbn = {1522-1598 (Electronic)\n0022-3077 (Linking)},
	author = {Neumeister, H and Whitaker, K W and Hofmann, H. A. and Preuss, T}
}
@article {7333,
	title = {Using comparative genomic hybridization to survey genomic sequence divergence across species: a proof-of-concept from Drosophila.},
	journal = {BMC Genomics},
	volume = {11},
	year = {2010},
	month = {2010///},
	pages = {271 - 271},
	abstract = {Genome-wide analysis of sequence divergence among species offers profound insights into the evolutionary processes that shape lineages. When full-genome sequencing is not feasible for a broad comparative study, we propose the use of array-based comparative genomic hybridization (aCGH) in order to identify orthologous genes with high sequence divergence. Here we discuss experimental design, statistical power, success rate, sources of variation and potential confounding factors. We used a spotted PCR product microarray platform from Drosophila melanogaster to assess sequence divergence on a gene-by-gene basis in three fully sequenced heterologous species (D. sechellia, D. simulans, and D. yakuba). Because complete genome assemblies are available for these species this study presents a powerful test for the use of aCGH as a tool to measure sequence divergence.},
	keywords = {Animals, Base Sequence, Comparative Genomic Hybridization, Drosophila, Drosophila melanogaster, Drosophila melanogaster: genetics, Drosophila: genetics, Genome, Microarray Analysis},
	isbn = {1471-2164},
	url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2873954\&tool=pmcentrez\&rendertype=abstract},
	author = {Renn, Suzy C. P. and Machado, Heather E and Jones, Albyn and Soneji, Kosha and Kulathinal, Rob J and Hofmann, Hans A.}
}
@article {7343,
	title = {Gene-expression signatures of Atlantic salmon{\textquoteright}s plastic life cycle},
	journal = {General and Comparative Endocrinology},
	volume = {163},
	number = {3},
	year = {2009},
	month = {2009///},
	pages = {278 - 284},
	publisher = {Elsevier Inc.},
	abstract = {How genomic expression differs as a function of life history variation is largely unknown. Atlantic salmon exhibits extreme alternative life histories. We defined the gene-expression signatures of wild-caught salmon at two different life stages by comparing the brain expression profiles of mature sneaker males and immature males, and early migrants and late migrants. In addition to life-stage-specific signatures, we discovered a surprisingly large gene set that was differentially regulated-at similar magnitudes, yet in opposite direction-in both life history transitions. We suggest that this co-variation is not a consequence of many independent cellular and molecular switches in the same direction but rather represents the molecular equivalent of a physiological shift orchestrated by one or very few master regulators. ?? 2009 Elsevier Inc. All rights reserved.},
	keywords = {Alternative reproductive tactics, ecological genomics, Gene Expression, Gene-expression signature, life history, Microarrays, migration, Module},
	isbn = {1095-6840},
	url = {http://dx.doi.org/10.1016/j.ygcen.2009.04.021},
	author = {Aubin-Horth, Nadia and Letcher, Benjamin H and Hofmann, Hans A.}
}
@article {7342,
	title = {Interspecific profiling of gene expression informed by comparative genomic hybridization: A review and a novel approach in African cichlid fishes},
	journal = {Integrative and Comparative Biology},
	volume = {49},
	number = {6},
	year = {2009},
	month = {2009///},
	pages = {644 - 659},
	abstract = {Modern genomic approaches have facilitated great progress in our understanding of the molecular and genetic underpinnings of ecological and evolutionary processes. Analysis of gene expression through heterologous hybridization in particular has enabled genome-scale studies in many ecologically and evolutionarily interesting species. However, these studies have been hampered by the difficulty of comparing-on a common array platform-gene-expression profiles across species due to sequence divergence altering the dynamics of hybridization. All too often, comparisons of expression profiles across species were limited to contrasting lists of gene or even of just functional categories. Here we review these issues and propose a novel solution. Exploiting the diverse cichlid lineages of East Africa as our model-system, we then present results from an experimental case study that compares the neural gene-expression profiles of males and females of two species that differ in mating system. Using a single microarray platform that contains genes from one species, Astatotilapia burtoni, we conducted a total of 16 direct comparisons for neural gene-expression level between individual males and females from a pair of sister species, the polygynous Enantiopus melanogenys and the monogamous Xenotilapia flavipinnis. Next, we conducted a meta-analysis with previously published data from two different intra-specific expression studies to determine whether sex-specific neural gene expression is more closely associated with behavioral phenotype than it is with gonadal sex. Our results indicate that the gene expression profiles are species-specific to a large extent, as relatively few genes show conserved expression patterns associated with either sex. Finally, we describe how competitive genomic DNA hybridizations between the two focal species allow us to assess the degree to which divergence of sequences biases the results. We propose a masking technique that correlates interspecific expression ratios obtained with cDNA with hybridization ratios obtained with genomic DNA for the same set of species and determines threshold sequence divergence to reduce false positives. Our approach should be applicable to a wide range of interesting questions related to the evolution and ecology of gene expression.},
	isbn = {1557-7023 (Electronic)\n1540-7063 (Linking)},
	author = {Machado, Heather E and Pollen, Alexander A and Hofmann, Hans A. and Renn, Suzy C. P.}
}
@article {7308,
	title = {Annotation of expressed sequence tags for the East African cichlid fish Astatotilapia burtoni and evolutionary analyses of cichlid ORFs.},
	journal = {BMC genomics},
	volume = {9},
	year = {2008},
	month = {2008///},
	pages = {96 - 96},
	abstract = {BACKGROUND: The cichlid fishes in general, and the exceptionally diverse East African haplochromine cichlids in particular, are famous examples of adaptive radiation and explosive speciation. Here we report the collection and annotation of more than 12,000 expressed sequence tags (ESTs) generated from three different cDNA libraries obtained from the East African haplochromine cichlid species Astatotilapia burtoni and Metriaclima zebra.\n\nRESULTS: We first annotated more than 12,000 newly generated cichlid ESTs using the Gene Ontology classification system. For evolutionary analyses, we combined these ESTs with all available sequence data for haplochromine cichlids, which resulted in a total of more than 45,000 ESTs. The ESTs represent a broad range of molecular functions and biological processes. We compared the haplochromine ESTs to sequence data from those available for other fish model systems such as pufferfish (Takifugu rubripes and Tetraodon nigroviridis), trout, and zebrafish. We characterized genes that show a faster or slower rate of base substitutions in haplochromine cichlids compared to other fish species, as this is indicative of a relaxed or reinforced selection regime. Four of these genes showed the signature of positive selection as revealed by calculating Ka/Ks ratios.\n\nCONCLUSION: About 22\% of the surveyed ESTs were found to have cichlid specific rate differences suggesting that these genes might play a role in lineage specific characteristics of cichlids. We also conclude that the four genes with a Ka/Ks ratio greater than one appear as good candidate genes for further work on the genetic basis of evolutionary success of haplochromine cichlid fishes.},
	keywords = {Animals, Cichlids, Cichlids: genetics, Evolution, Molecular, Expressed Sequence Tags, Gene Library, Open Reading Frames, Species Specificity, Tetraodontiformes, Tetraodontiformes: genetics},
	isbn = {1471-2164 (Electronic) 1471-2164 (Linking)},
	url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2279125\&tool=pmcentrez\&rendertype=abstract},
	author = {Salzburger, Walter and Renn, Susan C P and Steinke, Dirk and Braasch, Ingo and Hofmann, Hans A. and Meyer, Axel}
}
@article {7307,
	title = {Beyond neuroanatomy: Novel approaches to studying brain evolution},
	journal = {Brain, Behavior and Evolution},
	volume = {72},
	number = {2},
	year = {2008},
	month = {2008///},
	pages = {145 - 158},
	abstract = {The study of the evolution of brain structure and function, although fascinating, has been contentious, largely due to the correlative nature of neuroanatomical comparisons and the often ill-defined categorizations of habitat and behavior. We outline four conceptual approaches that will help the field of brain evolution emerge from a historical focus on descriptive comparative neuroanatomy. First, reliable, efficient and unbiased behavioral assays must be developed to characterize relevant cross-species differences in addition to focused studies of neuroanatomy. Second, developmental and physiological processes underlying neuroanatomical and behavioral differences can be analyzed using the comparative approach. Third, genome-wide comparisons including genome-wide linkage mapping, transcriptional profiling, and direct sequence comparisons, can be applied to identify the genetic basis for phenotypic differences. Finally, signatures of selection in DNA sequence can provide clues about adaptive genetic changes that affect the nervous system. These four approaches, which all depend on well-resolved phylogenies, will build on detailed neuroanatomical studies to provide a richer understanding of mechanistic and selective factors underlying brain evolution.},
	keywords = {Behavior, Brain development, Genomics, Molecular evolution, Neuroethology, phylogenetics},
	isbn = {1421-9743 (Electronic)\r0006-8977 (Linking)},
	author = {Pollen, Alexander A and Hofmann, Hans A.}
}
@article {7344,
	title = {Efficacy of RNA amplification is dependent on sequence characteristics: Implications for gene expression profiling using a cDNA microarray},
	journal = {Genomics},
	volume = {91},
	number = {1},
	year = {2008},
	month = {2008///},
	pages = {108 - 117},
	abstract = {Minute tissue samples or single cells increasingly provide the starting material for gene expression profiling, which often requires RNA amplification. Although much effort has been put into optimizing amplification protocols, the relative abundance of RNA templates in the amplified product is frequently biased. We applied a T7 polymerase-based technique to amplify RNA from two tissues of a cichlid fish and compared expression levels of unamplified and amplified RNA on a cDNA microarray. Amplification bias was generally minor and comprised features that were lost (1.3\%) or gained (2.5\%) through amplification and features that were scored as regulated before but unregulated after amplification (4.2\%) or vice versa (19.5\%). We examined 10 sequence-specific properties and found that GC content, folding energy, hairpin length and number, and lengths of poly(A) and poly(T) stretches significantly affected RNA amplification. We conclude that, if RNA amplification is used in gene expression studies, preceding experiments controlling for amplification bias should be performed. ?? 2007 Elsevier Inc. All rights reserved.},
	keywords = {Folding energy, GC content, Hairpin, Poly(A), Poly(T), RNA amplification bias, T7 polymerase},
	isbn = {1089-8646 (Electronic)\n0888-7543 (Linking)},
	author = {Duftner, Nina and Larkins-Ford, Jonah and Legendre, Matthieu and Hofmann, Hans A.}
}
@article {7306,
	title = {Expression of arginine vasotocin in distinct preoptic regions is associated with dominant and subordinate behaviour in an African cichlid fish},
	journal = {Proceedings of the Royal Society of London B: Biological Sciences},
	volume = {275},
	number = {1649},
	year = {2008},
	month = {2008///},
	pages = {2393 - 2402},
	abstract = {Neuropeptides have widespread modulatory effects on behaviour and physiology and are associated with phenotypic transitions in a variety of animals. Arginine vasotocin (AVT) is implicated in mediating alternative male phenotypes in teleost fish, but the direction of the association differs among species, with either higher or lower AVT related to more territorial behaviour in different fishes. To clarify the complex relationship between AVT and alternative phenotype, we evaluated AVT expression in an African cichlid in which social status is associated with divergent behaviour and physiology. We compared AVT mRNA expression between territorial and non-territorial (NT) males in both whole brains and microdissected anterior preoptic areas using transcription profiling, and in individual preoptic nuclei using in situ hybridization. These complementary methods revealed that in the posterior preoptic area (gigantocellular nucleus), territorial males exhibit higher levels of AVT expression than NT males. Conversely, in the anterior preoptic area (parvocellular nucleus), AVT expression is lower in territorial males than NT males. We further correlated AVT expression with behavioural and physiological characteristics of social status to gain insight into the divergent functions of individual AVT nuclei. Overall, our findings highlight a complex association between AVT and social behaviour.},
	keywords = {Dominance, Fish, Preoptic Area, social behaviour, Vasotocin},
	isbn = {0962-8452 (Print)\n0962-8452 (Linking)},
	url = {http://rspb.royalsocietypublishing.org/content/275/1649/2393\%5Cnhttp://dvg4ol0hclm7o.cloudfront.net//content/royprsb/275/1649/2393.full.pdf\%5Cnhttp://rspb.royalsocietypublishing.org/content/275/1649/2393.short\%5Cnhttp://www.ncbi.nlm.nih.gov/pubmed/1862811},
	author = {Greenwood, Anna K and Wark, Abigail R and Fernald, Russell D. and Hofmann, Hans A.}
}
@article {7305,
	title = {Fish and chips: functional genomics of social plasticity in an African cichlid fish},
	journal = {Journal of Experimental Biology},
	volume = {211},
	number = {18},
	year = {2008},
	month = {2008///},
	pages = {3041 - 3056},
	abstract = {... Arginine vasotocin {(AVT;} represented by multiple clones on the array), the non-mammalian homolog of arginine vasopressin {(AVP} ... In teleost fish , {AVT} is known to play a role in male mating tactics [peacock blenny {(Grober} et al., 2002; Carneiro et al., 2003); midshipman ...},
	keywords = {Behavior, cichlid, Microarray, Plasticity, Social Behavior},
	isbn = {0022-0949 (Print) 0022-0949 (Linking)},
	url = {http://jeb.biologists.org/content/211/18/3041.long\%5Cnhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.018242},
	author = {Renn, S C P and Aubin-Horth, N. and Hofmann, H. A.}
}
@article {7309,
	title = {Preface},
	journal = {Brain, Behavior and Evolution},
	volume = {72},
	number = {2},
	year = {2008},
	month = {2008///},
	pages = {89 - 90},
	author = {Hofmann, Hans A. and Shumway, Caroly A.}
}
@article {7310,
	title = {Sexual and social stimuli elicit rapid and contrasting genomic responses.},
	journal = {Proceedings of the Royal Society of London, Series B},
	volume = {275},
	number = {1633},
	year = {2008},
	month = {2008///},
	pages = {393 - 402},
	abstract = {Sensory physiology has been shown to influence female mate choice, yet little is known about the mechanisms within the brain that regulate this critical behaviour. Here we examine preference behaviour of 58 female swordtails, Xiphophorus nigrensis, in four different social environments (attractive and unattractive males, females only, non-attractive males only and asocial conditions) followed by neural gene expression profiling. We used a brain-specific cDNA microarray to identify patterns of genomic response and candidate genes, followed by quantitative PCR (qPCR) examination of gene expression with variation in behaviour. Our microarray results revealed patterns of genomic response differing more between classes of social stimuli than between presence versus absence of stimuli. We identified suites of genes showing diametrically opposed patterns of expression: genes that are turned {\textquoteright}on{\textquoteright} while females interact with attractive males are turned {\textquoteright}off{\textquoteright} when interacting with other females, and vice versa. Our qPCR results identified significant predictive relationships between five candidate genes and specific mate choice behaviours (preference and receptivity) across females exposed to males, with no significant patterns identified in female or asocial conditions or with overall locomotor activity. The identification of stimulus- and behaviour-specific responses opens an exciting window into the molecular pathways associated with social behaviour and mechanisms that underlie sexual selection.},
	keywords = {behavioural genomics, female preference, Mate choice, neural response},
	isbn = {0962-8452 (Print)\n0962-8452 (Linking)},
	author = {Cummings, Molly E and Larkins-Ford, Jonah and Reilly, Christian R L and Wong, Ryan Y and Ramsey, Mary and Hofmann, Hans A.}
}
@article {7312,
	title = {Environmental complexity and social organization sculpt the brain in Lake Tanganyikan cichlid fish},
	journal = {Brain, Behavior and Evolution},
	volume = {70},
	number = {1},
	year = {2007},
	month = {2007///},
	pages = {21 - 39},
	abstract = {Complex brains and behaviors have occurred repeatedly within vertebrate classes throughout evolution. What adaptive pressures drive such changes? Both environmental and social features have been implicated in the expansion of select brain structures, particularly the telencephalon. East African cichlid fishes provide a superb opportunity to analyze the social and ecological correlates of neural phenotypes and their evolution. As a result of rapid, recent, and repeated radiations, there are hundreds of closely-related species available for study, with an astonishing diversity in habitat preferences and social behaviors. In this study, we present quantitative ecological, social, and neuroanatomical data for closely-related species from the (monophyletic) Ectodini clade of Lake Tanganyikan cichlid fish. The species differed either in habitat preference or social organization. After accounting for phylogeny with independent contrasts, we find that environmental and social factors differentially affect the brain, with environmental factors showing a broader effect on a range of brain structures compared to social factors. Five out of seven of the brain measures show a relationship with habitat measures. Brain size and cerebellar size are positively correlated with species number (which is correlated with habitat complexity); the medulla and olfactory bulb are negatively correlated with habitat measures. The telencephalon shows a trend toward a positive correlation with rock size. In contrast, only two brain structures, the telencephalon and hypothalamus, are correlated with social factors. Telencephalic size is larger in monogamous species compared to polygamous species, as well as with increased numbers of individuals; monogamy is also associated with smaller hypothalamic size. Our results suggest that selection or drift can act independently on different brain regions as the species diverge into different habitats and social systems. Copyright {\textcopyright} 2007 S. Karger AG.},
	keywords = {Brain, cichlid, Ecology, Environmental complexity, Evolution, Fish, Habitat complexity, Social organization},
	isbn = {1421-9743 (Electronic) 0006-8977 (Linking)},
	author = {Pollen, Alexander A and Dobberfuhl, Adam P. and Scace, Justin and Igulu, Mathias M. and Renn, Susan C P and Shumway, Caroly A. and Hofmann, Hans A.}
}
@article {7313,
	title = {Masculinized dominant females in a cooperatively breeding species},
	journal = {Molecular Ecology},
	volume = {16},
	number = {7},
	year = {2007},
	month = {2007///},
	pages = {1349 - 1358},
	abstract = {The molecular mechanisms underlying complex social behaviours such as dominance are largely unknown. Studying the cooperatively breeding African cichlid Neolamprologus pulcher, we show that dominant females were similar to dominant males in dominance behaviour, high testosterone levels and brain arginine vasotocin expression (a neuropeptide involved in vertebrate territorial, reproductive and social behaviours) compared to subordinate helpers, but had lower levels of 11-ketotestosterone than males. Furthermore, brain gene expression profiles of dominant females were most similar to those of the males (independent of social rank). Dominant breeder females are masculinized at the molecular and hormonal level while being at the same time reproductively competent, suggesting a modular organization of molecular and endocrine functions, allowing for sex-specific regulation.},
	keywords = {Behaviour, Cooperative breeding, DNA microarray, Dominance, Gene Expression, Hormone, Integrative biology},
	isbn = {0962-1083 (Print)\n0962-1083 (Linking)},
	author = {Aubin-Horth, Nadia and Desjardins, Julie K. and Martei, Yehoda M. and Balshine, Sigal and Hofmann, Hans A.}
}
@article {7314,
	title = {Quantifying habitat complexity in aquatic ecosystems},
	journal = {Freshwater Biology},
	volume = {52},
	number = {6},
	year = {2007},
	month = {2007///},
	pages = {1065 - 1076},
	abstract = {Summary 1. Many aquatic studies have attempted to relate biological features, such as species diversity, abundance, brain size and behaviour, to measures of habitat complexity. Previous measures of habitat complexity have ranged from simple, habitat-specific variables, such as the number of twigs in a stream, to quantitative parameters of surface topography, such as rugosity. 2. We present a new video-based technique, called optical intensity, for assaying habitat complexity in aquatic ecosystems. Optical intensity is a visual, quantitative technique modifiable for any scale or for a nested analysis. We field-tested the technique in Lake Tanganyika, Tanzania, on 38 quadrats (5 x 5 m) to determine if three freshwater habitats (sand, rock and intermediate) were quantitatively different. 3. A comparison of the values obtained from optical intensity with a previous measure of surface topography (rugosity) showed that the two corresponded well and revealed clear differences among habitats. Both the new measure and rugosity were positively correlated with species diversity, species richness and abundance. Finally, whether used alone or in combination, both measures had predictive value for fish community parameters. 4. This new measure should prove useful to researchers exploring habitat complexity in both marine and freshwater systems.},
	keywords = {aquatic, Ecology, Optical intensity, Rugosity, Video},
	isbn = {0046-5070},
	author = {Shumway, Caroly A. and Hofmann, Hans A. and Dobberfuhl, Adam P.}
}
@article {7311,
	title = {Somatostatin and somatostatin receptor gene expression in dominant and subordinate males of an African cichlid fish},
	journal = {Behavioural Brain Research},
	volume = {179},
	number = {2},
	year = {2007},
	month = {2007///},
	pages = {314 - 320},
	abstract = {Somatostatin is a neuropeptide best known for its inhibitory effects on growth hormone secretion and has recently been implicated in the control of social behavior. Several somatostatin receptor subtypes have been identified in vertebrates, but the functional basis for this diversity is still unclear. Here we investigate the expression levels of the somatostatin prepropeptide and two of its receptors, sstR2, and sstR3, in the brains of socially dominant and subordinate Astatotilapia burtoni males using real-time PCR. Dominant males had higher somatostatin prepropeptide and sstR3 expression in hypothalamus compared to subordinate males. Hypothalamic sstR2 expression did not differ. There were no differences in gene expression in the telencephalon. We also observed an interesting difference between dominants and subordinates in the relationship between hypothalamic sstR2 expression and body size. As would be predicted based on the inhibitory effects of somatostatin on somatic growth, sstR2 expression was negatively correlated with body size in dominant males. In contrast sstR2 expression was positively correlated with body size in subordinate males. These results suggest that in A. burtoni social status affects the relationships between somatostatin prepropeptide and receptor gene expression in the hypothalamus and the control of somatic growth. ?? 2007 Elsevier B.V. All rights reserved.},
	keywords = {Aggression, Astatotilapia burtoni, Growth, Pre-optic area, Social Behavior},
	isbn = {0166-4328 (Print) 0166-4328 (Linking)},
	author = {Trainor, Brian C. and Hofmann, Hans A.}
}
@article {7315,
	title = {Gonadotropin-releasing hormone signaling in behavioral plasticity},
	journal = {Current Opinion in Neurobiology},
	volume = {16},
	number = {3},
	year = {2006},
	month = {2006///},
	pages = {343 - 350},
	abstract = {Sex and reproduction sculpt brain and behavior throughout life and evolution. In vertebrates, gonadotropin-releasing hormone (GnRH) is essential to these processes. Recent advances have uncovered novel regulatory mechanisms in GnRH signaling, such as the initiation of sexual maturation by kisspeptins. Yet despite our increasing molecular knowledge, we know very little about environmental influences on GnRH signaling and reproductive behavior. Alternative model systems have been crucial for understanding the plasticity of GnRH effects within an organismal context. For instance, GnRH signaling is under the control of seasonal cues in songbirds, whereas social signals regulate GnRH in cichlid fishes, with crucial consequences for reproduction and behavior. Analyzing cellular signaling cascades within an organismic context is essential for an integrative understanding of GnRH function. ?? 2006 Elsevier Ltd. All rights reserved.},
	isbn = {0959-4388 (Print) 0959-4388 (Linking)},
	author = {Hofmann, Hans A.}
}
@article {7316,
	title = {Somatostatin Regulates aggressive behavior in an african cichlid fish},
	journal = {Endocrinology},
	volume = {147},
	number = {11},
	year = {2006},
	month = {2006///},
	pages = {5119 - 5125},
	abstract = {Animals respond to environmental and social change with plasticity in the neural substrates underlying particular behavioral states. In the African cichlid fish Astatotilapia burtoni, social dominance status in males is accompanied by reduced somatic growth rate as well as increased somatostatin neuron size in the preoptic area. Although somatostatin is commonly studied within the context of growth, we show here for the first time that this ancient neuropeptide also plays a role in controlling social behavior. Somatostatin antagonists increased aggressive behavior in a dose-dependent fashion and the potent somatostatin agonist octreotide decreased aggression. We cloned and sequenced the genes encoding two somatostatin receptor subtypes in this species to study transcription in the gonads. When we examined somatostatin receptor gene expression in testes, expression of the somatostatin type 3 receptor was negatively correlated with an aggressive display and androgen levels. However, octreotide treatment did not reduce plasma testosterone or 11-ketotestosterone levels, suggesting that the behavioral effects of somatostatin are not mediated by androgens. These results show that somatostatin has important effects on social behavior. In dominant male A. burtoni, somatostatin may function to contain energetically costly processes such as somatic growth and aggressive behavior.},
	isbn = {0013-7227 (Print)\n0013-7227 (Linking)},
	author = {Trainor, Brian C. and Hofmann, Hans A.}
}
@article {7317,
	title = {Alternative life histories shape brain gene expression profiles in males of the same population},
	journal = {Proceedings of the Royal Society B: Biological Sciences},
	volume = {272},
	number = {1573},
	year = {2005},
	month = {2005///},
	pages = {1655 - 1662},
	abstract = {Atlantic salmon (Salmo salar) undergo spectacular marine migrations before homing to spawn in natal rivers. However, males that grow fastest early in life can adopt an alternative {\textquoteleft}sneaker{\textquoteright} tactic by maturing earlier at greatly reduced size without leaving freshwater. While the ultimate evolutionary causes have been well studied, virtually nothing is known about the molecular bases of this developmental plasticity. We investigate the nature and extent of coordinated molecular changes that accompany such a fundamental transformation by comparing the brain transcription profiles of wild mature sneaker males to age-matched immature males (future large anadromous males) and immature females. Of the ca. 3000 genes surveyed, 15\% are differentially expressed in the brains of the two male types. These genes are involved in a wide range of processes, including growth, reproduction and neural plasticity. Interestingly, despite the potential for wide variation in gene expression profiles among individuals sampled in nature, consistent patterns of gene expression were found for individuals of the same reproductive tactic. Notably, gene expression patterns in immature males were different both from immature females and sneakers, indicating that delayed maturation and sea migration by immature males, the {\textquoteleft}default{\textquoteright} life cycle, may actually result from an active inhibition of development into a sneaker.},
	keywords = {Behaviour, Brain, Gene Expression, Microarray, Plasticity, Reproduction},
	isbn = {0962-8452},
	url = {http://rspb.royalsocietypublishing.org/content/272/1573/1655\%5Cnhttp://rspb.royalsocietypublishing.org/content/272/1573/1655.full.pdf\%5Cnhttp://rspb.royalsocietypublishing.org/content/272/1573/1655.short\%5Cnhttp://www.ncbi.nlm.nih.gov/pubmed/16087419},
	author = {Aubin-Horth, Nadia and Landry, Christian R and Letcher, Benjamin H and Hofmann, Hans A.}
}
@article {7318,
	title = {Interaction of rearing environment and reproductive tactic on gene expression profiles in Atlantic salmon},
	journal = {Journal of Heredity},
	volume = {96},
	number = {3},
	year = {2005},
	month = {2005///},
	pages = {261 - 278},
	abstract = {Organisms that share the same genotype can develop into divergent phenotypes, depending on environmental conditions. In Atlantic salmon, young males of the same age can be found either as sneakers or immature males that are future anadromous fish. Just as the organism-level phenotype varies between divergent male developmental trajectories, brain gene expression is expected to vary as well. We hypothesized that rearing environment can also have an important effect on gene expression in the brain and possibly interact with the reproductive tactic adopted. We tested this hypothesis by comparing brain gene expression profiles of the two male tactics in fish from the same population that were reared in either a natural stream or under laboratory conditions. We found that expression of certain genes was affected by rearing environment only, while others varied between male reproductive tactics independent of rearing environment. Finally, more than half of all genes that showed variable expression varied between the two male tactics only in one environment. Thus, in these fish, very different molecular pathways can give rise to similar macro-phenotypes depending on rearing environment. This result gives important insights into the molecular underpinnings of developmental plasticity in relationship to the environment.},
	isbn = {0022-1503},
	author = {Aubin-Horth, N. and Letcher, B. H. and Hofmann, H. A.}
}
@article {7319,
	title = {Biologically meaningful expression profiling across species using heterologous hybridization to a cDNA microarray.},
	journal = {BMC genomics},
	volume = {5},
	number = {1},
	year = {2004},
	month = {2004///},
	pages = {42 - 42},
	abstract = {BACKGROUND: Unravelling the path from genotype to phenotype, as it is influenced by an organism{\textquoteright}s environment, is one of the central goals in biology. Gene expression profiling by means of microarrays has become very prominent in this endeavour, although resources exist only for relatively few model systems. As genomics has matured into a comparative research program, expression profiling now also provides a powerful tool for non-traditional model systems to elucidate the molecular basis of complex traits.\n\nRESULTS: Here we present a microarray constructed with approximately 4500 features, derived from a brain-specific cDNA library for the African cichlid fish Astatotilapia burtoni (Perciformes). Heterologous hybridization, targeting RNA to an array constructed for a different species, is used for eight different fish species. We quantified the concordance in gene expression profiles across these species (number of genes and fold-changes). Although most robust when target RNA is derived from closely related species (\&lt;10 MA divergence time), our results showed consistent profiles for other closely related taxa (approximately 65 MA divergence time) and, to a lesser extent, even very distantly related species (\&gt;200 MA divergence time).\n\nCONCLUSION: This strategy overcomes some of the restrictions imposed on model systems that are of importance for evolutionary and ecological studies, but for which only limited sequence information is available. Our work validates the use of expression profiling for functional genomics within a comparative framework and provides a foundation for the molecular and cellular analysis of complex traits in a wide range of organisms.},
	keywords = {Animals, Brain Chemistry, Cichlids, Cichlids: classification, Cichlids: genetics, Cyprinodontiformes, Cyprinodontiformes: genetics, DNA, Complementary, DNA, Complementary: genetics, Gene Expression Profiling, Gene Expression Profiling: methods, Gene Pool, Nerve Tissue Proteins, Nerve Tissue Proteins: genetics, Nucleic Acid Hybridization, Oligonucleotide Array Sequence Analysis, Poecilia, Poecilia: genetics, Salmo salar, Salmo salar: genetics, Species Specificity, Tilapia, Tilapia: genetics, Zebrafish, Zebrafish: genetics},
	isbn = {1471216454},
	url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=471549\&tool=pmcentrez\&rendertype=abstract},
	author = {Renn, Susan C P and Aubin-Horth, Nadia and Hofmann, Hans A.}
}
@article {7320,
	title = {Functional genomics of neural and behavioral plasticity},
	journal = {Journal of Neurobiology},
	volume = {54},
	number = {1},
	year = {2003},
	month = {2003///},
	pages = {272 - 282},
	abstract = {How does the environment, particularly the social environment, influence brain and behavior and what are the underlying physiologic, molecular, and genetic mechanisms? Adaptations of brain and behavior to changes in the social or physical environment are common in the animal world, either as short-term (i.e., modulatory) or as long-term modifications (e.g., via gene expression changes) in behavioral or physiologic properties. The study of the mechanisms and constraints underlying these dynamic changes requires model systems that offer plastic phenotypes as well as a sufficient level of quantifiable behavioral complexity while being accessible at the physiological and molecular level. In this article, I explore how the new field of functional genomics can contribute to an understanding of the complex relationship between genome and environment that results in highly plastic phenotypes. This approach will lead to the discovery of genes under environmental control and provide the basis for the study of the interrelationship between an individual{\textquoteright}s gene expression profile and its social phenotype in a given environmental context.},
	keywords = {Brain and behavior, Genomics, Neural and behavioral plasticity},
	isbn = {0022-3034 (Print) 0022-3034 (Linking)},
	author = {Hofmann, Hans A.}
}
@article {7322,
	title = {Assessment of strength and willingness to fight during aggressive encounters in crickets*},
	journal = {Animal Behaviour},
	volume = {62},
	year = {2001},
	month = {2001///},
	pages = {337 - 348},
	abstract = {Game theory predicts that at least some of the behaviour patterns displayed during aggressive encounters are used to assess asymmetries in variables that indicate fighting ability and resource value. Game theoretical models such as the sequential assessment game see assessment as the major activity during a fight. However, while these models acknowledge the existence of physical and motivational assessment parameters, there are only a few examples where a mechanism for the assessment of fighting readiness has been shown. In staged encounters between male Mediterranean field crickets, Gryllus bimaculatus, fighting behaviour follows a stereotyped escalation cascade with ritualized displays in the beginning and physical combat towards the end. Despite their larger size, heavier animals lost 30\% of the encounters even if weight asymmetry was large. To examine whether the contestants provide assessment cues that might explain this surprising result, we analysed two stereotyped displays in detail (antennal fencing and mandible spreading). The duration of antennal fencing, which is necessary to initiate a fight, was independent of experience and weight asymmetry between the contestants, but was prolonged after shortening the antennae by almost 90\%. Fights escalated only when antennal movement frequencies were high in both contestants. In blinded crickets few contests were settled by another ritualized display, mandible spreading, and fights that escalated beyond this stage were significantly shorter than in untreated crickets. We suggest that antennal fencing may be used to assess fighting readiness of the opponent, while mandible spreading may indicate fighting ability. We conclude that high willingness to fight may help crickets to overcome inferior fighting ability.},
	isbn = {0003-3472},
	url = {http://www.idealibrary.com},
	author = {Hofmann, Hans A. and Schildberger, Klaus}
}
@booklet {7321,
	title = {What cichlids tell us about the social regulation of brain and behaviour},
	journal = {Journal of aquaculture and aquatic sciences},
	volume = {9},
	year = {2001},
	month = {2001///},
	pages = {17 - 31},
	author = {Hofmann, H. A. and Fernald, R D}
}
@article {7323,
	title = {The fight and flight responses of crick - PubMed Mobile},
	journal = {J Neurobiol.},
	volume = {43},
	year = {2000},
	month = {2000///},
	pages = {107 - 20},
	keywords = {Aggression, do-, escape behavior, octopamine},
	url = {https://webvpn.uni-leipzig.de/+CSCO+00756767633A2F2F6A6A6A2E61706F762E61797A2E6176752E746269++/m/pubmed/-CSCO-3b--10770840/},
	author = {Stevenson, Paul a and Hofmann, Hans A. and Schoch, K and Schildberger, Klaus}
}
@article {7324,
	title = {Flight restores fight in crickets.},
	journal = {Nature},
	volume = {403},
	year = {2000},
	month = {2000///},
	pages = {613 - 613},
	abstract = {Aggressiveness recovers much faster in male crickets forced to fly after a defeat},
	isbn = {0028-0836},
	author = {Hofmann, H. A. and Stevenson, P a}
}
@article {7275,
	title = {Social status controls somatostatin neuron size and growth},
	journal = {Journal of Neuroscience},
	volume = {20},
	number = {12},
	year = {2000},
	month = {2000///},
	pages = {4740 - 4744},
	abstract = {Many animal species show flexible behavioral responses to environmental and social changes. Such responses typically require changes in the neural substrate responsible for particular behavioral states. We have shown previously in the African cichlid fish, Haplochromis burtoni, that changes in social status, including events such as losing or winning a territorial encounter, result in changes in somatic growth rate. Here we demonstrate for the first time that changes in social status cause changes in the size of neurons involved in the control of growth. Specifically, somatostatin-containing neurons in the hypothalamus of H. burtoni increase up to threefold in volume in dominant and socially descending animals compared with cell sizes in subordinate and socially ascending fish. Because somatostatin is known to be an inhibitor of growth hormone release, the differences in cell size suggest a possible mechanism to account for the more rapid growth rates of subordinate and socially ascending animals compared with those of dominant or socially descending fish. These results reveal possible mechanisms responsible for socially induced physiological plasticity that allow animals to shift resources from reproduction to growth or vice versa depending on the social context.},
	keywords = {1993, after individuals, Cichlid fish, Dominance, francis et al, have been studied in, however, life history, neuron size, phenotypic plasticity, social status, somatostatin, stable social situations or, tanks, the, were moved to new},
	isbn = {0270-6474 (Print) 0270-6474 (Linking)},
	url = {http://www.jneurosci.org/content/20/12/4740.short},
	author = {Hofmann, Hans A. and Fernald, Russell D.}
}
@article {7276,
	title = {Social status regulates growth rate: consequences for life-history strategies.},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {96},
	number = {24},
	year = {1999},
	month = {1999},
	pages = {14171 - 6},
	abstract = {The life-history strategies of organisms are sculpted over evolutionary time by the relative prospects of present and future reproductive success. As a consequence, animals of many species show flexible behavioral responses to environmental and social change. Here we show that disruption of the habitat of a colony of African cichlid fish, Haplochromis burtoni (G{\"u}nther) caused males to switch social status more frequently than animals kept in a stable environment. H. burtoni males can be either reproductively active, guarding a territory, or reproductively inactive (nonterritorial). Although on average 25-50\% of the males are territorial in both the stable and unstable environments, during the 20-week study, nearly two-thirds of the animals became territorial for at least 1 week. Moreover, many fish changed social status several times. Surprisingly, the induced changes in social status caused changes in somatic growth. Nonterritorial males and animals ascending in social rank showed an increased growth rate whereas territorial males and animals descending in social rank slowed their growth rate or even shrank. Similar behavioral and physiological changes are caused by social change in animals kept in stable environmental conditions, although at a lower rate. This suggests that differential growth, in interaction with environmental conditions, is a central mechanism underlying the changes in social status. Such reversible phenotypic plasticity in a crucial life-history trait may have evolved to enable animals to shift resources from reproduction to growth or vice versa, depending on present and future reproductive prospects.},
	keywords = {Animals, Perches, Perches: growth \& development, Social Behavior},
	isbn = {0027-8424 (Print)\n0027-8424 (Linking)},
	url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=24209\&tool=pmcentrez\&rendertype=abstract},
	author = {Hofmann, Hans A. and Benson, M E and Fernald, R D}
}
@booklet {7277,
	title = {Verhandlungen zur Geschichte und Theorie der Biologie},
	year = {1999},
	month = {1999///},
	pages = {51 - 58},
	author = {Hofmann, Hans A. and Rickli, Hannes}
}
