Paternal experience suppresses adult neurogenesis without altering hippocampal function in Peromyscus californicus

Paternal care is rare among mammals, occurring in ≈6% of species. California mice (Peromyscus californicus) are unusual; fathers participate extensively in raising their young and display the same components of parental care as mothers, with the exception of nursing. Parenting is a complex experience, having stressful and enriching aspects. The hippocampus is sensitive to experience and responds to both stress and environmental enrichment with changes in structure and function. In rats, where females care exclusively for offspring, parenting is associated with suppressed hippocampal adult neurogenesis. Since this effect has been causally linked to lactation, it is unlikely that fathers would show a similar change. To investigate this issue, we examined adult neurogenesis in the hippocampus of California mouse fathers compared to males without pups and observed reduced adult neurogenesis. Similar effects were found in California mouse mothers. Next, we investigated whether behaviors linked to the hippocampus, namely, object recognition and novelty-suppressed feeding, were altered in fathers, and observed no substantial changes. During caregiving, suppressed adult neurogenesis does not appear to be related to changes in behaviors associated with the hippocampus, although it is possible that there are other effects on hippocampal function.