Motherhood Improves Memory?

Many new moms complain of feeling dull-witted from anxiety and lack of sleep. But a new study suggests -- in rats, at least -- that motherhood may sharpen the mind.

Researchers at the University of Richmond say hormones produced by rats during pregnancy, combined with the stimulation gained from caring for offspring, apparently improve the animals' memory and learning skills.

The researchers suspect the rodents' brains make new neural connections as a result of the sensory stimulation -- sights, sounds and cuddling -- that parenting provides.

And the benefits are not necessarily limited to biological mothers. Rats that had never given birth but served as foster parents performed better when finding food hidden in an enclosure.

The benefits of brighter mothers are obvious, even if the cause of the postpartum mental improvement isn't clear.

Anything that makes a rat mother more efficient "translates into better survivability for her and her offspring," said Craig Kinsley, a professor of neuroscience who lead the research, published in Thursday's issue of the journal Nature.

Bruce McEwen, a professor of neuro-endocrinology at Rockefeller University in New York, said the study is intriguing but doesn't prove a link between motherhood and actual changes in the rats' brains.

"They didn't really look into the brain. They just look at the animals' behavior, which is of course the first step. But there's a lot of information that we just don't have at this point," he said.

In one test that gauged memory, Kinsley's team placed three groups of rats in a circular enclosure with eight wells containing cereal. After eating their fill, the rats were removed and cereal was dropped into only one of the wells.

The rats were then periodically returned to the enclosure with the same well filled each time with cereal. The rats that had never given birth or cared for pups took the longest on average -- 128 seconds -- to find the food.

Rats that had never given birth but were protecting and keeping warm other rats' offspring found the food in about 55 seconds, while mother rats caring for their own young did so in about 43 seconds.

The research, of course, does not necessarily apply to humans. It's no secret that many women don't feel at the peak of their mental abilities after childbirth.

"Right after birth, so much of your energy goes into just learning to keep the baby alive, and of course you're incredibly sleep-deprived, more than any measure you've had before," said Lisa Bain, executive editor of Parenting, magazine and herself a mother. "I can't imagine feeling smarter. I certainly didn't feel sharper."

In addition, a 1997 study found that women had a harder time learning new information just before childbirth.

J. Galen Buckwalter, a gerontology professor at the University of Southern California who led that study, said hlooked at verbal memory, while the rat study focused on spatial memory. Still, he said, his research found that spatial perception improved in pregnant women and for six weeks after childbirth.

"Exactly what all this means remains to be seen. It raises a number of questions we need to look at more carefully in human studies," he said.