I was in the midst of the most rapid and dramatic neurobiological change of my adult life. The unmooring I felt, and that so many new mothers feel, likely was at least in part a manifestation of structural and functional brain changes, handed down through the millennia by mothers past and intended to mold me into a fiercely protective, motivated caregiver, focused on my baby’s survival and long-term well-being.
…Women experience a flood of hormones during pregnancy, childbirth, and breast-feeding that primes the brain for dramatic change in regions thought to make up the maternal circuit. Affected brain regions include those that enable a mother to multitask to meet baby’s needs, help her to empathize with her infant’s pain and emotions, and regulate how she responds to positive stimuli (such as baby’s coo) or to perceived threats. In the newborn months, a mother’s interaction with her infant serves as further stimulus to link her brain quite tangibly to her baby’s.
…After childbirth, the volume of gray matter in the mothers’ brains changed dramatically, particularly in regions involved in social processes and “theory of mind,” or the ability to attribute emotions and mental states to other people — key in raising a human. The degree of change, enough that researchers could easily sort the women who had had a pregnancy from those who hadn’t, surprised Elseline Hoekzema, a lead author on the 2016 paper who studies pregnancy and the brain at Leiden University in the Netherlands.
…Studies have found that fathers, including gay fathers raising children without maternal involvement, experience significant changes in brain activity, but those changes depend on exposure to the child. The more time a man spends as primary caregiver, the more activated the parental network in his brain becomes, and researchers suspect a similar effect may be present for others in a parental role.
…A surge of oxytocin at childbirth triggers changes that allow a woman quite literally to sync to her baby through a coordination of biology (synchronized brain responses and heart rates) and behavior (matching responses in gaze, touch, and vocalizations). That intense connection teaches a baby from the very first day how to relate to another person, says Ruth Feldman, Simms-Mann Professor of Developmental Neuroscience at the Interdisciplinary Center in Herzliya, Israel. When we connect with friends, romantic partners, and colleagues and even as we view ourselves as a member of a sports team or as part of a nation, we “repurpose the basic machinery” established in the connection between mother and baby, she explained in a 2017 paper on the neurobiology of human attachment.
The parental brain incorporates human-specific functions such as empathy with ancient ones aimed at protecting the young for the survival of the species. That complexity makes it “a peak expression of human evolution,” she says. In fact, she speculates that the parental bonding phenomenon came first. Before there were humans.