Mommy’s Brain
January 24, 2006
by Lindsay Carswell, Sciencentral News

We all know motherhood changes the body. But research in animals shows it also changes the brain. Parenting seems to enhance learning and memory in both moms and dads.

Parental Complexity
Coping day or night with the demands of a new born baby and worrying over every cough and sniffle are just in a day's work for parents, but it's something that people without kids often find hard to imagine being able to do… until they have kids of their own that is. So where do that cool head, that parenting instinct and those coping skills just materialize from?

Sleep-deprived new mothers might find it hard to believe, but having kids may actually make you sharper. Brain researcher Kelly Lambert says that, at least in rodents, pregnancy and parenting change the brain and behavior in ways that go beyond nursing and nurturing.

"From what we've seen, having a whole different being to take care of requires a whole new set of skills and a lot more awareness, cognitive awareness and multi-tasking," explains Lambert, professor and Chair of the psychology department at Randolph-Macon College.

As Lambert and her collaborator Craig Kinsley, of the University of Richmond, wrote in Scientific American, mother rats outperform non-mothers at searching for food. Lambert found that the mother rats' brains have increased complexity in an area involved in this type of memory. "They have a wonderful search strategy and we don't see these in the animals that have never been moms, our virgin rats," she explains. The moms are also bolder than non-moms at exploring the winding passages of an elevated maze.

"When I was expecting my first baby I had to read books and go to the hospital to take classes," she says. "I was amazed when I would look at the cages where these rat moms knew immediately what to do as soon as they started having these pups."

In most of the mammalian models they looked at, the female is a single mom. "The dads don't hang around to take care of the pups, so she has to go beyond the nest to forage, to find food for her pups," Lambert explains. "In our rodent models the moms have 13 or 14 pups, so this has a lot of energy demands for the mom… they needed to explore and get back, and we know that moms defend their nest."

Lambert, Kinsley and others have shown some brain changes are triggered by the surges of hormones that accompany motherhood, and they last into old age. "A day of exposure to these hormones results in increased complexity in these neurons, or nerve cells, in the hippocampus," says Lambert. "So we were thinking that if this happens just over the course of several hours, then what happens when the female actually goes through pregnancy, and she's exposed to these higher levels of hormone associated with a pregnancy for a lot longer period of time."

"Perhaps the hormones associated with pregnancy and lactation and motherhood kind of prime the brain so that it can respond to the changes, the many changes, that are about to happen as an animal becomes a mom," she says.

Changes like being exposed to those needy offspring. Could that alone alter the brain? Lambert showed it could, by giving pups to rats that weren't mothers. She found the same mental benefits in a species of mice in which the dads help care for the pups.

"Right now it's looking like this is an enriching experience for the brain," she says.

Lambert has also found that mother rats have lower levels of stress hormones, and less of the substance that forms toxic brain plaques in Alzheimer's disease. "So there might be some neural benefits with aging in a sense that this experience, maybe not unlike other enriched environments, may provide a buffer or some protection against some of these neurodegenerative disorders that animals and humans get in old age," she says.

While the researchers plan to look for similar effects in people, the research so far goes to show that although it may sometimes feel like it, parenting is much more than a rat race.

Lambert's work was published in the August 2005 issue of Behavioral Neuroscience and was featured in Scientific American, January 2006. It was funded by the National Institutes of Health, Randolph-Macon College, and the University of Richmond.