The parental brain: transformations and adaptations

Few evolutionary transformations rival the complex neurobiological modifications accompanying the mammalian transition to parenthood. Research conducted primarily in maternal rodents highlights the engagement of multiple areas of the brain to initiate and maintain interest in resource-depleting vulnerable pups throughout lactation. Interestingly, many modifications marking the transition to motherhood result in adaptive response options that persist well beyond the weaning of pups; specifically, adaptations such as cognitive flexibility, emotional regulation and enhanced social attentiveness coincide with the parenthood transition and have emerged as defining characteristics of the most adaptive mammalian species. The paternal brain also results in interesting modifications that, in some biparental species, mimic the effects observed in females. Taken together, research suggests that the designation of "parent" is less of a categorical variable and more of a continuous variable, with the quality of nurturing responses directed toward offspring influenced by many factors such as predisposed sensitivity to reproductive hormones, nature and duration of exposure to offspring, number of reproductive experiences, adequate resources, and composition of the social environment. Indeed, the transition from an animal focused on self-preservation to one that is responsive to the needs of other animals, and the accompanying increases in reproductive fitness, represent a significant evolutionary transition, or upgrade of sorts, leading to a more diverse array of response options to meet the challenging demands of changing environmental and social terrains.