Natural variations of adult neurogenesis and anxiety predict hierarchical status of inbred mice

Abstract

Hierarchy provides a survival advantage to social animals in challenging circumstances. In mice, social dominance is associated with trait anxiety and reduced stress resilience which are regulated by adult hippocampal neurogenesis. Here, we tested whether adult hippocampal neurogenesis may regulate social dominance behavior. We observed that future dominant individuals exhibited higher trait anxiety and lower levels of hippocampal neurogenesis prior to social hierarchy formation, suggesting that baseline neurogenesis might predict individual social status among a group. This phenotype persisted after social hierarchy was stable. Experimentally reducing neurogenesis prior to the stabilization of social hierarchy in group-housed males increased the probability of mice to become dominant and increased anxiety. Finally, when innate dominance was assessed in socially isolated and anxiety-matched animals, mice with impaired neurogenesis displayed a dominant status toward strangers. Together, these results indicate that adult neurogenesis predicts and regulates hierarchical and situational dominance behavior along with anxiety-related behavior. These results provide a framework to study the mechanisms underlying social hierarchy and the dysregulation of dominance behavior in psychiatric diseases related to anxiety.