Motherhood may make women smarter--perhaps permanently--as hormones released during pregnancy and nursing dramatically enrich parts of the brain involved in learning and memory, new animal studies suggest.
The findings, made public at a meeting of the Society for Neuroscience in Los Angeles, are among a series of emerging insights into how the subtle ebb and flow of sex hormones change the brain.
Indeed, so responsive is the female brain to changing hormone levels that aspects of neural cell structure appear to change during the course of a monthly cycle, new research indicates. Overall, researchers are discovering that, compared to the male brain, the female brain retains a remarkable capacity for change throughout a lifetime.
The enriching effects of child-bearing were discovered in an unusual series of experiments with laboratory animals by neuroscientists at the University of Richmond and Randolph Macon College in Virginia, who wanted to understand what effect the higher hormone levels of pregnancy had on brain structures involved in learning and memory.
Pictures of the brains reveal that special brain cell structures called dendrites--essential for communication between neurons--doubled in pregnant and nursing laboratory animals. At the same time, the number of the brain's glial cells, which act as scaffolding and communication conduits, also doubled.
The mothering mice were bolder, more curious and energetic. They learned mazes more quickly, made fewer mistakes, and retained their new knowledge longer. And the effects appeared to be long-lasting, researchers found.
"We are seeing significant changes," said Richmond neuro-psychologist Craig H. Kinsley, who conducted the study with Randolph Macon psychologist Kelly Lambert. "Pregnancy, a perfectly natural biological experience for the female, appears to mark the brain for a lifetime.
"In a way, the brain of a late-pregnant female resembles a toy factory at Christmastime, receiving orders and gearing up for the increased demands about to be placed on it," Kinsley said. "It looks like this does something to make their learning much more efficient than females without that experience. It suggests there is a permanent change in that female's behavior, reflective of some sort of permanent change in the brain."
Findings at Odds With USC Research
