Effect of relative social rank within a social hierarchy on neural activation in response to familiar or unfamiliar social signals

Competent social functioning of group-living species relies on the ability of individuals to detect and utilize conspecific social cues to guide behavior. In many species, cues about an individual9s identity, including social status, are conveyed through urinary proteins. Previous studies have identified numerous brain regions involved in processing these external cues, collectively referred to as the Social Decision-Making Network. However, how the brain encodes social information with respect to an individual9s internal social status has not been thoroughly examined. Here we show that neuronal activity in male mice, as indicated by cFos immunoreactivity, is modulated by the social status and familiarity of the cue source and the subject9s own social status. The posteroventral medial amygdala was the only brain region that responded exclusively to the social status of the cue source. Activity in other brain regions was modulated by social status. Specifically, within the brain of dominant subjects there was robust differential activity dependent on the status or familiarity of the cue source. Our results suggest that individuals perceive social cues differently depending on their social experience. These data inform further the investigation of neurobiological mechanisms underlying social-status related brain differences and how social status-associated differences influence physiology and behavior.