I've got a friend somewhere: control of social behavior across striatal subregions

Most animals and humans are inherently social, enabling group dynamics to promote survival. Despite their importance, how the brain calibrates appropriate social behaviors to maximize survival and benefits remains incompletely understood. Distributed networks of neural circuits mediate complex behavioral states, including social behaviors. The striatum has long-known to be a structure essential for motivation and goal-directed behavior. The striatum is massive: it extends far along the anterior-posterior axis and can be divided into ventral, dorsal, and posterior domains. While it is well-appreciated that these striatal domains control motivated behaviors through coordinated functions, such that ventral striatum (e.g., nucleus accumbens) governs motivation and rewards processing, dorsal striatum mediates motor planning and action selection, and the posterior striatum (i.e., tail of the striatum) integrates sensory inputs, much less is understood about how they modulate social interactions. This mini review discusses the current understanding of what aspects of social behavior are controlled by each striatal subregion. We focus on key studies that highlight prominent neuromodulators, such as dopamine, serotonin, and neuropeptides, and their roles in social behaviors. We propose a framework in which striatal subregions calibrate social interaction through coordinated activities that mediate distinct aspects of the social interaction, similar to general motivation. A deeper understanding of how distributed striatal circuits modulate social behavior will help inform the development of therapeutic approaches for social dysfunction in various psychiatric states.