The Role of Early Life Experience in Shaping the Neural Mechanisms of Paternal Care Behavior in the African Striped Mouse (Rhabdomys pumilio)

Abstract

Early life experiences have profound effects on the development of social behavior, including parental care. However, the neurobiological mechanisms that ultimately drive and influence paternal care behavior, while hypothesized to be closely associated with the various mechanisms affecting maternal care, are still unknown. Correspondingly, the question presented in this research project asks how juvenile social experiences (social isolation versus social groups during peri-adolescent development) alter paternal behavior in a biparental mammalian species. Specifically, this study will employ a relatively novel African striped mice model to study the impact of experience-dependent variation on paternal behavior within a single species. Furthermore, we strived to understand whether these early experiences alter patterns of response to pup stimuli in brain regions known for their role in parental behavior (e.g., the MPOA) or if reward-associated regions are more affected, as parental behavior is widely regarded as a natural reward-directed behavior. Accordingly, we hypothesized that socially isolated male African striped mice will showcase decreased activity in parental care-associated brain regions while generally being more anxious and stressed. To assess this, a series of behavioral tests were applied (e.g., the open field test and the light/dark box test). Following these assessments, we utilized immunohistochemistry and microscopy to identify patterns of expression of the immediate early gene c-Fos. C-Fos expression was then quantified to determine the brain regions most affected by early social variation during acute paternal behavior tasks. Overall, we discovered little to no differences in anxiety-related and exploratory behavior, while socially isolated male African striped mice were found to exhibit greater responses of paternal care behavior than the group-living males. Major differences were also found in the level of c-Fos expression for pup-exposed mice over empty-cage mice, specifically in the MPOA, pointing to its potential significance in the circuitry of paternal care.