AN INVESTIGATION OF THE ROLE OF AMYGDALAR CIRCUITS IN THE PRODUCTION OF SOCIAL BEHAVIOR

Adaptive social behaviors allow animals to survive, thrive, and successfully reproduce. These behaviors, including mating, parenting, affiliation, and aggression, can be stereotyped in response to specific stimuli but often display sex-specific, and interoceptive-dependent variations in their execution. A conserved set of brain regions collectively known as the social behavior network (SBN) interprets sensory information about social cues and generates an appropriate behavioral response. In this dissertation I present 5 chapters. Chapter 1 introduces historical research focusing on the neural circuits that drive social behavior and the potential impact of environmental factors on the activity of these circuits. Chapter 2 describes a new technique that uses magnetohydrodynamic-based tissue clearing to investigate intact neural circuits rapidly and efficiently. Chapter 3 uses this approach to interrogate the synaptic connections of a primary hub for social sensory integration, the medial amygdala (MeA). I focused on neurons in the MeA that express an enzyme that plays an important role in the development of sex-specific social behaviors: aromatase and identified the sources of synaptic input to this population. These inputs included regions involved in maintaining metabolic homeostasis, production of socio-sexual behaviors, fear/anxiety, parenting, and aggressive behaviors –suggesting an expanded view of social behavior production. I demonstrate that the brain regions involved in the production of social behavior have broad access to internal physiological and external environmental information. Chapter 4, demonstrates the impact of external environmental factors on the behaviors produced in response to a social stimulus, as well as, on the early sensory representation of these stimuli in the AOB. Predator presence influences an animals’ responses to conspecific stimuli even when not presented concurrently. This effect was observed in males and females and in response to male and female stimuli, demonstrating a generalizable impact of environmental conditions on the sensory representation of social stimuli. Chapter 5 summarizes these findings in a broader context, arguing for an expanded role for the SBN in integrating internal and external environmental information with sensory perceptions of social stimuli to produce appropriate behavioral response for not only a specific social stimulus, but a specific environmental context