Species-typical group size differentially influences social reward neural circuitry during nonreproductive social interactions

• Authors: Jose Gonzalez A Abreu, Emory University; Ashley E Rosenberg, Emory University; Brandon A Fricker, Emory University; Kelly Wallace, Emory University; Ashley W Seifert, University of Kentucky; Aubrey Kelly, Emory University
• Journal Title: ISCIENCE
• Volume: Volume 25, Number 5
• Publisher: CELL PRESS | 2022-05-20, Pages 104230-104230
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1016/j.isci.2022.104230
• Subjects: Psychology, General; Biology, General
• Keywords: Science & Technology; Multidisciplinary Sciences; Science & Technology - Other Topics; VENTRAL TEGMENTAL AREA; TYROSINE-HYDROXYLASE; SEXUAL-BEHAVIOR; PARAVENTRICULAR NUCLEUS; MONGOLIAN GERBILS; OXYTOCIN NEURONS; DOPAMINE NEURONS; CATECHOLAMINERGIC NEURONS; MATERNAL-BEHAVIOR; ACOMYS-DIMIDIATUS

Abstract

We 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.