As the father of 12-week-old twins, I was intrigued to see a new paper has been published looking at the brain changes associated with fatherhood. Before now, nearly all human research on the neural effects of parenting has been focused on mothers.
When you become a dad, it's like a plate has been set spinning in your brain (or two in my case) – suddenly, no matter where you are, or what you're doing, you have this restless vigilance for your fragile offspring. And then there's the time spent playing and feeding, when you're alert to every flicker of emotion on their little face, every tiny hiccup or cry. It would be incredible if these new responsibilities and ways of interacting didn't have a profound effect on the brain.
A team led by Pilyoung Kim at the Universities of Denver and Yale twice scanned the brains of 16 new fathers (average age 36; 7 were first-time dads). The first scan took place between 2 and 4 weeks after their babies were born; the second scan 12 to 16 weeks later. Previous research has shown functional changes in the brains of fathers, in the way that they show heightened neural activity in response to the sight of their own infants. However, this is the first time that researchers have documented structural changes in the brains of human fathers.
Comparing the later scan with the first scan, Kim's team found increased grey matter volume in several regions of the fathers' brains. This included areas previously identified as showing growth in new mothers, including the striatum (involved in reward processing, among other functions), hypothalamus (hormonal control), amygdala and anterior cingulate cortex (ACC; involved in emotional processing), and the lateral pre-frontal cortex (PFC; involved in memory and decision making). The PFC is one of the areas that has been associated with heightened activity when fathers view their own infants. Prior monkey research has also shown an increase in branching between neurons in the PFC of fathers.