Access to running wheels decreases social motivation in adult C57BL/6J female mice

Physical activity offers myriad benefits to health and well-being, in humans and other animals as well. In rodents, voluntary wheel running can attenuate the effects of both physical and social stressors on rodent social behavior. Whether wheel running affects rodent social behaviors per se remains less well understood. We conducted the current study to test whether home cage access to running wheels impacts the social behaviors of adult, group-housed C57BL/6J female mice during same-sex interactions with novel females. Group-housed females were either given continuous home cage running wheel access or a standard paper hut starting at weaning, and as adults, the social behaviors of females from these two groups were measured during interactions with novel female mice. In two cohorts of females, we found that 5 weeks of running wheel access during adolescence reduced the time that female subjects spent engaged in social investigation of a novel female and also tended to reduce total ultrasonic vocalizations produced during interactions. These effects were not reversed by a 2-week period in which running wheels were removed. Finally, we found that a 2-week period of running wheel access in adulthood recapitulates the effects of 5 weeks of running wheel access on female social investigation. Overall, we find that running wheel access has an enduring inhibitory influence on female social behavior during same-sex interactions, a finding that has implications for the design of studies that include same-sex interactions between female mice.