Evidence for the involvement of a fronto-striatal pathway in the processing of social reward

Social interactions are a hallmark of animal behavior and is essential for survival, cooperation, and reproduction. Despite its necessity, the neural mechanisms that drive social behavior, particularly the rewarding nature of social interactions, are not fully understood. Social behaviors are inherently rewarding, and this intrinsic value plays a key role in reinforcing and shaping social engagement. A growing body of work has sought to quantify social reward in rodents using behavioral paradigms such as social conditioned place preference and operant social motivation tasks, offering translational tools to probe underlying circuit mechanisms. Historically, this research has centered on the mesolimbic dopamine pathway, particularly the ventral tegmental area and its projections to the nucleus accumbens. However, emerging evidence supports a complementary role for prefrontal cortical (PFC) circuits in modulating social motivation and reward. The PFC integrates contextual and social information via distinct neuronal populations and exerts top-down control over behavior through its projections to subcortical targets such as the ventral striatum (vSTR). While prior research has implicated the PFC-vSTR pathway in general aspects of social behavior, its specific contribution to the encoding of social reward remains poorly defined. Here, we synthesize existing findings and propose a novel mechanism in which prefrontal parvalbumin (PV) interneurons regulate social reward by modulating PFC-vSTR output. We further consider how neuromodulators such as oxytocin and dopamine interact with this circuit to further influence social behavior. Elucidating the microcircuit-level control of social reward has significant implications for neuropsychiatric disorders, including autism spectrum disorder and schizophrenia, where social motivation and reward processing are often disrupted.