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Evolution of Social Brains
- The document discusses the evolution of social brains in animals from different perspectives including differences in brain regions, genes, molecules, and behaviors between species. - Key findings include that similar brain regions regulate social behaviors across species, including the mesolimbic reward system and social behavior network, and that similar genes and molecules like dopamine and vasopressin influence social behaviors in all animals. - Differences in behaviors between species arise from quantitative differences in the activity of these shared neuromolecular systems, influenced by ecology and other factors, giving rise to diversity in mating systems and other social decisions.
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Evolution of Social Brains
- 1. Evolution of SocialBrains Rayna M. Harris Graduate Researcher, Hans Hofmann’s Lab rayna.harris@utexas.edu raynamharris@github.io Comparative Animal Physiology (BIO 361T) April 7, 2016 1
- 2.
- 3. Brains are awesomelydiverse and complex! 3
- 4. Learning, memory, and thehippocampus 4
- 5. Evolution of SocialBrains • Bird, frog, fish, reptile, and mammal brains • Brain regions and molecules that regulate aggressive and mating behavior • Differences in mating systems 5
- 6. “Endless forms mostbeautiful and wonderful” Fish Amphibians Reptiles Birds Mammals 6
- 7. Animal brains arevery diverse as well! Amphibians Reptiles Birds Mammals Fish 7
- 8. Ecology can shapebrain size! Somatosensory (touch) cortex Auditory (echolocation) cortex Visual cortex “…the fittest succeed in adapting themselves best to their environment.” 8
- 9. What else couldgive rise to the similarities and differences in animal brains? 9
- 10. Hox genes controlbody development in all animals! Hox Genes Developing embryos Adults Rodents Nobel Prize: 1995: Lewis, Nüsslein-Volhard, and Wieschaus Flies Fish 10
- 11. Do similar genescontrol brain development? Amphibians Reptiles Birds Mammals Fish O'Connell & Hofmann, 2011 & 2012 11
- 12. Yes, similar genescontrol brain development! Amphibians Reptiles Birds Mammals Fish O'Connell & Hofmann, 2011a & 2012 12
- 13. What decisions doanimals (including humans) make? 13
- 14. Some categories ofdecision making Find foodFind mates Find shelter Care for family Fight competitors 14
- 15. All animals facechallengesand opportunities O'Connell & Hofmann, 2011b 15
- 16. Some brain regionsregulate social behaviors Dopaminergic Reward System Social Behavior NetworkSocial Decision Making Network O'Connell & Hofmann, 2011a & 2012 16
- 17. Do the samebrain regions control social behavior in all animals? Fish Amphibians Reptiles Birds Mammals O'Connell & Hofmann, 2011a & 2012 17
- 18. Yes, the samebrain regions control behavior! Mesolimbic Reward System Newman’s Social Behavior Network Shared by both circuits Fish O'Connell & Hofmann, 2011a & 2012 18
- 19. Do the samemolecules control behavior in all animals? Signaling Molecules Receptors O'Connell & Hofmann, 2011a & 2012 19
- 20. Some molecules areknown to influence animal social behavior Dopamine Vasopressin Testosterone Estradiol 20
- 21. How conserved isgene activity in the same brain regions? O'Connell & Hofmann 2012 Androgen receptor Estrogen receptor Progesterone receptor Dopamine receptor Vasopressin receptor Oxytocin receptor Vasopressin Oxytocin Tyrosine hydroxylase 21 • Which molecules in the striatum are present in all species examined? • Which molecules in the striatum are absent in all species examined? • Which two pairs of species are more similar to each other than to the rest?
- 22. How conserved isgene activity in the same brain regions? O'Connell & Hofmann 2012 22 Androgen receptor Estrogen receptor Progesterone receptor Dopamine receptor Vasopressin receptor Oxytocin receptor Vasopressin Oxytocin Tyrosine hydroxylase • What are the most striking similarities and differences in gene expression between the striatum and the proptic area
- 23. How conserved isgene activity in the same brain regions? Where signals are received is well conserved Where signals are produced is less conserved. 12 brain regions * 10 genes = 120 rows O'Connell & Hofmann 2012 23
- 24. Social animals usesimilar neuromolecular networks to generate similar behaviors Fish Amphibians Reptiles Birds Mammals 24
- 25. If all brainsare made of the same parts, how what gives rise to diversity in behavior? 25
- 26. Differences in decisionmaking Find foodFind mates Find shelter Care for family Fight competitors 26
- 27. How does diversityin mating system arise? Neuromolecular networks that regulates mating system Monogamy Polygamy Oldfield et al. 2013 27
- 28. Herichthys cichlid fishes Herichthyscyanoguttatus Texas Cichlid Herichthys minckleyi Cuatro Cienegas Cichlid Oldfield et al. 2013 28
- 29. Does behavior changewhen levels of these neurochemical change? • V1aR, OTR, D1, D2 • ER, PR, AR Dopamine Arginine Vasopressin Testosterone Estradiol 29
- 30. This experiment integrates ecology,endocrinology, and molecular biology 1. Catch fish in Shoal Creek 2. Collect blood 3. Dissect brains 4. Quantify hormone levels 5. Extract RNA 6. Quantify gene expression Oldfield et al. 2013 30
- 31. 11-ketotestosterone is higherin haremic males Monogamous Haremic High testosterone often leads to: • Decreased paternal care • Increased Aggression Oldfield et al. 2013 31
- 32. Vasopressin Receptor activityis higher in the hypothalamus of haremic males Monogamous Haremic High vasopresin receptor is often associated with • Increased aggression • Increased territory size • Important for social behavior Oldfield et al. 2013 32
- 33. Diversity in socialbehavior is a result of quantitative differences in neuromolecular activity Fish Birds Mammals 33
- 34. Links to thefour papers discussed • O’Connell LA, Hofmann HA (2011a) The vertebrate mesolimbic reward system and social behavior network: A comparative synthesis. Journal of Comparative Neurology. 519:3599-639. PDF • O'Connell LA, Hofmann, HA (2011b) Genes, hormones, and circuits: An integrative approach to study the evolution of social behavior. Frontiers in Neuroendocrinology 32:320–335. PDF • O'Connell LA & Hofmann HA (2012) Evolution of a Vertebrate Social Decision-Making Network. Science 336, 1154-1157. PDF • Oldfield RG, Harris RM, Hendrickson DA, Hofmann HA (2013) Arginine Vasotocin and Androgen Pathways are Associated with Mating System Variation in North American Cichlid Fishes. Hormones and Behavior 64, 44–52. PDF 34
- 35. Acknowledgements Hans Hofmann Lab TheUniversity of Texas at Austin rayna.harris@utexas.edu raynamharris@github.io 35