Summary: Researchers found that fathers’ brains changed significantly before and after birth. The main changes occurred in cortical areas associated with visual processing, attention and empathy for infants.
Over the past 50 years, the weekly hours that American fathers spend caring for their children has tripled. The increase in parental participation by fathers was even greater in countries such as Germany, Spain, Sweden, and Iceland that expanded paid paternity leave or created incentives for fathers to take time off. A growing body of research has found that children of engaged fathers perform better on a range of outcomes, including physical health and cognitive abilities.
Despite fathers’ increasing involvement in childcare and the important role they play in their children’s lives, there has been surprisingly little research on how fatherhood affects men. Fewer studies have focused on brain and biological changes that might support patriarchy.
Not surprisingly, the transition to parenthood can be transformative for anyone with a newborn. For women who become biological mothers, the hormonal changes associated with pregnancy help explain why new mothers’ brains may change.
But does fatherhood rewire men’s brains and bodies in ways that motivate them to become parents — without directly experiencing pregnancy? We set out to investigate this question in our recent study of first-time fathers in two countries.
What pregnancy does to the new mother’s brain
Recent research has found compelling evidence that pregnancy can enhance neuroplasticity, or remodeling, of a woman’s brain structure. Using magnetic resonance imaging, researchers have discovered large-scale changes in the anatomy of women’s brains before and after pregnancy.
In one study, researchers in Spain scanned first-time mothers before they became pregnant and again two months after they gave birth. Compared with childless women, new mothers have smaller brain volumes, suggesting that key brain structures actually shrink during pregnancy and the early postpartum period.
The changes in the brain were so pronounced that an algorithm could easily distinguish the brains of pregnant women from those of childless women.
Across the brain, these changes were seen in gray matter, the neuron-rich layer of tissue in the brain. Pregnancy appears to affect the structure of the cerebral cortex — the recently evolved outer surface of the brain — including an area associated with thinking about other people’s thoughts, a process researchers call “theory of mind.”
The mothers also showed brain changes in the subcortex — older structures located deep in the brain that are associated with more primitive functions, including emotion and motivation.
Why do these brain structural changes occur after pregnancy?
The researchers believe these brain changes may contribute to mothers’ sensitive care of their newborns, who require constant attention and are unable to verbalize their needs. In fact, when mothers look at photos or videos of their babies, it activates many of the same brain regions that change the most throughout pregnancy. It seems plausible that new mothers’ brains would change to help them respond to and care for their newborns.
But what about fathers? They don’t get pregnant directly, but may also care for the newborn.
dad’s brain changes too
As with practicing any new skill, the experience of caring for a baby can leave an imprint on a new parent’s brain. This is what neuroscientists call experience-induced brain plasticity—like the brain changes that happen when you learn a new language or master a new musical instrument.
A small but growing number of studies are looking at this plasticity in fathers who experience the cognitive, physical and emotional demands of caring for a newborn without pregnancy.
For example, in terms of brain function, gay fathers who were primary caregivers showed stronger connections between parenting brain regions when they observed their infants compared with secondary male caregivers.
To learn more about brain plasticity in new dads, our research groups at the University of Southern California in Los Angeles and the Instituto de Investigación Sanitaria Gregorio Marañón in Madrid conducted a new study in collaboration with the BeMother project.
We recruited 40 men — 20 in Spain and 20 in California — and put each of them into an MRI scanner twice: once during their partner’s pregnancy, and again during their child’s After 6 months of age. We also included a control group of 17 childless men.
We found some significant changes in the brains of fathers from prenatal to postpartum that were not present in the childless men we followed over the same period.
In the Spanish and California samples, the fathers showed brain changes in cortical areas that help with visual processing, attention and empathy for infants.
What rewires the new father’s brain?
The degree of brain plasticity in fathers may be related to how well they interact with their babies. Although fathers in many parts of the world are increasingly involved in parenting, the level of father involvement varies widely among different men.
This range of involvement could explain why we found more subtle brain changes in these fathers than in first-time mothers. In fact, fathers’ brains changed almost half as much as mothers’ brains.
Social, cultural and psychological factors that determine how much fathers interact with their children may in turn affect changes in the father’s brain. In fact, Hispanic fathers, who on average take more paternity leave than American fathers, show more pronounced changes in brain regions that support goal-directed attention than Californians, which may help fathers tune in to their babies’ cues. them.
This finding raises the question of whether family policies that increase the amount of time fathers spend on infant care in the early postpartum period help support paternal brain development.
On the other hand, perhaps men who exhibited more brain and hormonal remodeling were also more motivated to participate in hands-on care.
More research is needed to tease out these questions and figure out how best to intervene with fathers who may have difficulty adjusting to their parenting roles.
Despite the importance of fathers to their children’s development, funding agencies have not tended to prioritize research into male fatherhood, but that may start to change as more such findings emerge.
Future studies with more detailed measurements of postpartum care could reveal more about brain plasticity in both male and female parents.
About this parenting and neuroscience research news
author: Darby Saxbe and Magdalena Martínez García
touch: Darby Saxbe and Magdalena Martínez García – A Conversation
picture: This image is in the public domain