摘要：SummaryWe investigated whether nonreproductive social interactions may be rewarding for colonial but not non-colonial species. We found that the colonial spiny mouse (Acomys cahirinus) is significantly more gregarious, more prosocial, and less aggressive than its non-colonial relative, the Mongolian gerbil (Meriones unguiculatus). In an immediate-early gene study, we examined oxytocin (OT) and tyrosine hydroxylase (TH) neural responses to interactions with a novel, same-sex conspecific or a novel object. The paraventricular nucleus of the hypothalamus (PVN) OT cell group was more responsive to interactions with a conspecific compared to a novel object in both species. However, the ventral tegmental area (VTA) TH cell group showed differential responses only in spiny mice. Further, PVN OT and VTA TH neural responses positively correlated in spiny mice, suggesting functional connectivity. These results suggest that colonial species may have evolved neural mechanisms associated with reward in novel, nonreproductive social contexts to promote large group-living.Graphical abstractDisplay OmittedHighlights•Spiny mice are more gregarious, more prosocial, and less aggressive than gerbils•PVN OT neurons are responsive to novel social interactions in spiny mice and gerbils•VTA TH neuronal responses are greater in response to social stimuli in spiny mice•PVN OT and VTA TH functional connectivity may gate social reward in spiny miceBiological sciences; Ethology; Cellular neuroscience
