Dr. Darby Saxbe

And so those are sort of shared, but then there are some differences in how they emerge and when they emerge for both mothers and fathers.

So in mothers, it looks like the brain starts to remodel in pregnancy and in the early postpartum period.

And the influence of pregnancy hormones is probably driving a lot of that remodeling.

For fathers, it looks more like a story of experience-dependent plasticity.

So where we think there's change happening in dads is...

as they start to interact with babies and spend time with them.

So I found in my lab, we see bigger changes to father's brains when they report spending more time with kids and when they find interactions with their kids to be more engaging.

So it's father's motivation that seems to play a really important role in what's happening to men's brains.

But where you see the changes are in some of the same parts of the brain.

Yeah, so what we see from prenatal to postpartum in both moms and dads sounds scary to some folks, but we think is adaptive, which is a loss of gray matter volume.

So when we're losing brain volume, it's tempting to adopt kind of a deficit framework.

that you have less brain, but it actually seems to reflect a process of becoming more efficient and more streamlined.

So we also lose gray matter volume in early childhood as we prepare for school age, for example, right?

Like it reflects a process of learning

And we kind of become canalized along certain pathways.

And so where you see volume reductions are in what's called the mentalizing network.

And that's the part of the brain that helps us think about other people's minds.

And it's considered kind of a seat of empathy.

And so you see some kind of shrinkage and streamlining in those areas when you compare

expectant moms and early postpartum moms, as well as expectant dads and early postpartum dads, you seem to be seeing this shrinkage across the transition to parenthood.