Developmental, cellular and circuit mechanisms for social behaviors in the limbic system across sexes.

National Institute Of Environmental Health Sciences

Investigators

Abstract

Social behaviors, such as mating, aggression, and parental care are crucial for survival and propagation and, therefore, shared across species. These behaviors are considered innate as they are unlearned and can take place without prior experience. We utilize the murine limbic system as an entry-point, in particular the medial amygdala (MeA), as these regions process social sensory information and are implicated in the generation of appropriate motor output responses for social behaviors. Given that these diverse social behaviors differ in their sensory trigger and behavioral outcomes, can the neuronal substrates for these behaviors be distinct? To this end, we take a developmental approach to study developmentally-defined neuronal subpopulations across the limbic system. We hypothesize that transcription factor expression is going to be predictive of sex-specific neuronal activity, function and circuitry in the amygdala and hypothalamus. To test this hypothesis, we take a multi-level approach to determine: 1) neuronal responses at the population and single-cell level using fiber photometry and miniature endoscopic imaging, respectively; 2) circuit connectivity via anterograde and retrograde tracing experiments; 3) function in social behaviors by undertaking chemogenetic and optogenetic approaches. Additionally, we study the neuronal mechanisms giving rise to social behaviors in infancy and adolescence and investigate how these mechanisms can be disrupted due to adverse environmental experiences. These studies will provide a unified framework of the interplay between nature (developmental mechanisms) and nature (environment) for shaping social information processing and social behaviors. Elucidating the basic mechanisms of social behaviors across postnatal development is crucial for improving treatment options for disorders with a high social component such as autism and conduct disorder.