When women become mothers, their brains begin to change rapidly. A new study suggests that these changes prime some (but not all) mothers to respond to facial cues from newborns and that, when the system works as it should, the end result is stronger mother-infant bonding. The new data lines up with previous findings indicating that fundamental changes to the brains of new parents help mothers and fathers both adapt to their new familial responsibilities.
“Our findings support the idea that, in the brain, responses to infants’ cues change over the course of … early motherhood, with some mothers showing more marked changes than others,” said co-author on the study David Haley of the University of Toronto, in a statement. “This variation is associated with mothers’ reports of their emotional bonds with their babies.”
Scientists have long known that parenthood comes with significant neurobiological changes, many of them geared toward helping parents identify their children. Among Prairie Voles, studies have shown that new fathers tend to acquire a fresh set of neurons and dendrites in the hippocampus (the brain region involved in memory and learning), just for the purpose of helping them recognize their new brood. And in humans, at least one study that examined parents with fMRI brain scans found that parents were more closely attuned to photographs of children than the general population — likely an artifact of the brain having shifted to nurture children.
But Haley and colleagues were interested in a more specific question. Are there changes in the maternal brain during pregnancy, they wondered, and could this be associated with bonding once the baby is born? So they surveyed 39 pregnant women from Toronto and used EEG scans and simple child-related activities. They concluded that parents with more significant changes to their brains during pregnancy — whose brains responded most strongly when shown images of children — were far more likely to report positive relationships with their babies.
One serious limitation of this study is that it does not make clear whether brain changes lead to bonding, whether bonding causes brain changes, or whether this entire observation is based on a correlation. Haley and his team recognize this and plan to pursue further research to better understand the mechanisms at play.
“The next steps in our research are to examine how emotional and cognitive networks in the brain communicate, and whether changes in neural connectivity between these networks are related to how parents understand and respond to the emotional signals of their infants,” co-author Joanna Dudek, also of the University of Toronto, said in a statement.