Introducing the brain: changes in pregnancy (Introduction)

by David Turell , Saturday, January 13, 2024, 18:57 (313 days ago) @ David Turell

Some areas decrease in size and then regrow:

https://www.newscientist.com/article/2412048-some-brain-regions-shrink-in-pregnancy-and...

"Brain scans show that some brain regions become smaller and thinner during pregnancy, and that most of these changes reverse after giving birth. This suggests the brain is restructuring itself during and immediately after pregnancy, potentially to prepare for parenthood.

“'Pregnancy is probably the most intense hormonal event that a human being can go through. So, it was reasonable to think the brain will change during pregnancy,” says Susana Carmona at the General University Hospital Gregorio Marañón in Spain.

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"The researchers found significant changes in the cortex, or the outer region of the brain, during and after pregnancy. On average, the cortex was 2.5 per cent thinner and 4.6 per cent smaller in volume in pregnant women than in those who didn’t have children. Most of these differences attenuated in the postpartum period, except in two brain networks called the default mode network and frontoparietal network. Regions in these networks were at least 2 per cent thinner and almost 3.6 per cent smaller in volume in new mothers than in women who didn’t have children.

"The default mode network is critical for self-perception and social interaction, and the frontoparietal network is important in executive functions like planning and carrying out tasks. More data is needed to elucidate why pregnancy alters these networks, but one widely accepted hypothesis is these changes help prepare for parenthood, says Catherine Monk at Columbia University in New York.

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"It would make sense for the brain to refine pathways in these regions to facilitate empathising and caring for a child, says Carmona. “If you ask any mother, most of them will tell you, ‘I feel completely different [after giving birth].’ These changes might be behind this feeling, but we still don’t know,” says Carmona.

"Yet, the fact that most cortical changes reverse in postpartum suggests another, more dynamic mechanism is also at play. Carmona believes this might be widespread decreases in microglia, the brain’s immune cells. “Your whole immune system has to adapt so you can gestate a person that is genetically different from you, and we know that microglia change shape and number pretty quickly,” she says. (my bold)

"These findings could also help us better understand neurological and mental health conditions associated with pregnancy, like postpartum depression, says Carmona. “It’s important to realise that parenting begins before birth,” says Monk. “There’s so much brain plasticity and change happening that we could get in there, then, to promote optimal wellbeing. And that could help families get off to a better start.'”

Comment: these changes in size cannot be loss of neurons, since that number is fixed for life. My bold is a key point. A mother is harboring a stranger for nine months without having her immune system reject him. A vital aspect of pregnancy .