Dad's Brain May Become More 'Maternal' When He's...
Regions where emotions are processed get more active, researchers report
The mothers showed more activity in the amygdala and other emotion-processing structures than fathers -- in fact, their amygdala activity was five times that of the fathers who had taken a secondary role in child-rearing.
"They are the worriers," Feldman said. "They are much more primed by pregnancy and childbirth to be aware of infant danger signals."
On the other hand, the fathers showed more activity in their superior temporal sulcus, a region of the brain involved in logical tasks related to social interaction. It is crucial to processing social cues, reading facial expressions and processing speech.
"In fathers, their parenting is guided much more by understanding and empathizing in a cognitive way," Feldman said.
But when a man takes on the primary caregiving role -- in this case, as part of a committed homosexual relationship -- both "parenting" regions of the brain become highly active, researchers found.
"They have the father's cognitive structures, but the amygdala is sensitive to child-care experiences and it can activate to the level of mothers," Feldman said.
The degree of connectivity between the two brain regions in all fathers correlated with the amount of time spent taking care of the child, suggesting that fathers' brains adapt to a more active parenting role.
"The more fathers are involved in active caregiving, the more the fathering network will activate the mothering network," Feldman said.
Jeannie Bertoli, a relationship and family counselor based in Woodland Hills, Calif., noted that the research did not include any families where the father was the primary caregiver and the mother had assumed a secondary role.
She hopes that follow-up research will look at whether mothers can lose the amygdala-driven bond established through childbirth after they've rejoined the workforce.
It also will be important to test whether brain changes occur in men who are primary caregivers in a heterosexual relationship, Bertoli added.
In addition to the amygdala finding, the researchers also linked activity in all parts of the brain's parenting network to the release of oxytocin, which Feldman said serves as the "love" and "bonding" hormone that rewards togetherness and caring.