Isolation rearing attenuates social interaction-induced expression of immediate early gene protein products in the medial prefrontal cortex of male and female rats

► Increased aggressive behaviors were observed in isolation-reared males and females. ► Social interaction increased c-fos and Arc in the prefrontal cortex (PFC) in group-reared rats. ► Isolation rearing eliminated the increases in c-fos and Arc protein in the PFC. ► Sex differences in Arc and BDNF were observed in subregions of the PFC. ► Negative correlations between social behaviors and expression of proteins of interest.