SYSTEMS CONSOLIDATION MECHANISM OF SOCIAL MEMORY IN MICE

Social recognition memory is critical for survival, which often reported to be impaired in various neurodevelopmental disorders including autism spectrum disorder (ASD). Social behaviors are often affected by both genetic and environmental factors, which provide valuable insight into our understanding of normal social behaviors. We found that juvenile social isolation followed by re-socialization which induces a selective deficit in social recognition reduces mPFC neurons projecting to the nucleus accumbens (NAc). Bi-directional chemogenetic manipulations of this pathway showed that the mPFC to NAc circuit is critical for social recognition. Intriguingly, we found that NAc-projecting mPFC neurons are activated when a mouse interacts with a familiar conspecific. Furthermore, inactivating NAc-projecting mPFC neurons that responded to a familiar conspecific impaired the recognition of other familiar mice, demonstrating that these neuronal population encodes social familiarity. Furthermore, inactivating hippocampal ventral CA1 neurons projecting to the IL disrupted the consolidation of memory for newly familiarized mice while sparing the recognition of littermates. These findings demonstrate that hippocampal-cortical interactions play critical roles in social memory consolidation in mice.