Strange but true: Becoming a father shrinks your brain

Several studies conducted previously have shown that becoming a mother can change the structure of a woman’s brain, however, very few studies have examined the neuroanatomic adaptations of men transitioning into fatherhood.

But now, new international research has identified neurological changes amongst first-time fathers as well.

Published in the journal, Cerebral Cortex, the study suggests that the neural substrates of parenthood are not exclusive to mothers. Fathers, too, can also be impacted by their new role as a parent, but in a less pronounced and uniform way.

Researchers found that on average, the new fathers lost a percentage or two of cortical volume, following the birth of their first child.

According to experts, though a loss in cortical volume might sound like a bad thing at first, but it can actually indicate an improvement of the brain that makes bonding with a child stronger and more effective.

Similar cortical losses found in mothers, for instance, are associated with greater neural responses to a child and stronger attachment between mother and child.

For the first-time fathers, it was found that this shrinkage of the cortical volume was mainly confined to an area of the brain known as the 'default mode network' which is associated with parental acceptance and warmth for their child.

Default mode network is a neural system which is implicated in aspects of cognition and psychopathology.

Though previous studies have reportedly found subtle neurological changes in a first-time father’s brain, following the birth of his child, however, the little evidence that has been collected regarding this subject, has proved to be conflicting and varied.

This new study is more accurate than most as the research is based on magnetic resonance imaging (MRI) data from 40 heterosexual first-time fathers.

For this study, while half of the men were based in the US the other half were based in Spain.

The expectant dads in Spain participated in brain scans before their partners' pregnancies, and then again, a few months after the birth of their child, Science Alert, informs.

On the other hand, the expectant dads in the US, participated during the mid-to-late stages of their partners' pregnancy, and then again seven to eight months postpartum.

The new research also included a control group of 17 men based in Spain, who didn’t have children.

The two laboratories responsible for the research reportedly gathered all their data to compare the thickness, volume, and structural properties of the male brains in each of the three groups.

It was discovered that in comparison to similar studies on new mothers, first-time dads, in the current study did not show any changes in their limbic subcortical network. This makes sense, as this part of the brain is associated with pregnancy hormones, states Science Alert.

According to the study, fathers, don’t carry their offspring as they grow and develop but this doesn’t mean their brains are not affected by parenthood.

In the current study, researchers observed that the first-time dads in both Spain and in the US did not show changes in their subcortex, which is associated with reward and motivation.

However, it was found that they did show signs of brain plasticity in their cortical gray matter, which is largely involved in social understanding.

Researchers also reportedly found pronounced reductions in the visual system's volume, which aligns with a recent study in 2020, that found fathers are better at visual memory tasks than men who don’t have children.

The authors of the new study are quoted as saying, “These findings may suggest a unique role of the visual system in helping fathers to recognize their infants and respond accordingly, a hypothesis to be confirmed by future studies,"

They add, "Understanding how the structural changes associated with fatherhood translate into parenting and child outcomes is a largely unexplored topic, providing exciting avenues for future research."