Circuits underlying social function and dysfunction

Substantial advances have been made toward understanding the genetic and environmental risk factors for autism, a neurodevelopmental disorder with social impairment as a core feature. In combination with optogenetic and chemogenetic tools to manipulate neural circuits in vivo, it is now possible to use model systems to test how specific neural circuits underlie social function and dysfunction. Here, we review the literature that has identified circuits associated with social interest (sociability), social reward, social memory, dominance, and aggression, and we outline a preliminary roadmap of the neural circuits driving these social behaviors. We highlight the neural circuitry underlying each behavioral domain, as well as develop an interactive map of how these circuits overlap across domains. We find that some of the circuits underlying social behavior are general and are involved in the control of multiple behavioral aspects, whereas other circuits appear to be specialized for specific aspects of social behavior. Our overlapping circuit map therefore helps to delineate the circuits involved in the various domains of social behavior and to identify gaps in knowledge. Lay Summary Difficulties with social function are a core feature of autism, and we currently lack a clear understanding of the brain circuitry underlying social behaviors. We reviewed the literature that has identified brain nodes and circuits associated with social interest, the rewarding nature of social interactions, memory for social partners, dominance, and aggression in rodents. Our review, which reveals that some nodes/circuits may be involved in the control of many aspects of social behaviors, whereas other nodes/circuits appear to specialize in the control of specific behaviors, identifies gaps in our current understanding of these circuits.