Natural variations in maternal behavior shape anxiety and hippocampal neurogenesis in offspring

Subtle variations in nontraumatic early-life experience are associated with long-lasting trajectories in pups’ brain development and behavior. Understanding the mechanisms of individualization of emotional traits is crucial for the development of personalized medicine in mood disorders. Although previous research focused on genetic differences or experimental manipulations of maternal care, it is unclear whether natural variations in maternal care in the absence of genetic variability influence anxiety-related behavior and neurogenesis. We addressed this question by observing inbred mouse maternal care and offspring in a longitudinal manner. We found that mothers spontaneously displaying low maternal care showed lower adult neurogenesis in both the olfactory bulb and the hippocampus compared with high maternal care mothers. In turn, low maternal care–reared pups exhibited increased anxiety as compared to high maternal care–reared pups, which was associated with decreased postnatal neurogenesis after weaning. These results highlight that in the absence of genetic diversity, natural variations in early-life experience are sufficient to shape brain plasticity and anxiety-related behavior in offspring. This underscores the relevance of maternal care and hippocampal neurogenesis in shaping personality-like traits related to mood disorders and inducing emotional individuality in early stages of life.