By Jenifer Goodwin

HealthDay Reporter

MONDAY, Jan. 30, 2012 (HealthDay News) -- Preschool children whose moms are loving and nurturing have a larger hippocampus, an area of the brain involved in learning, memory and stress response, when they reach school age, a new study finds.

"It is to our knowledge the first study that links early maternal nurturance to the structural development of a key brain region," said study author Dr. Joan Luby, a professor of psychiatry at Washington University School of Medicine in St. Louis. "It provides very powerful evidence of the importance of early nurturing for healthy brain development and has tremendous public health implications."

In the study, researchers conducted an experiment in which children aged 3 to 6 were put into a frustrating situation. The kids and their mothers were left in a room with a brightly wrapped package. The kids were told they could open the gift, but they had to wait while the mom filled out a series of forms.

Researchers observed how the kids and their parents handled this situation, which was meant to replicate the typical stressors of daily parenting -- that is, mom is trying to get something done, and the child needs to control their impulses despite being faced with something they want right at that moment.

Mothers who offered reassurance and support that helped their child regulate their emotions and control their impulses were rated as being nurturing. Mothers who either ignored the child or harshly scolded the child were rated otherwise.

When the children were between 7 and 10 years old, researchers did MRI brain scans of 92 of the kids who participated in that earlier experiment.

Kids with the nurturing moms had a hippocampus that was 10 percent larger than the hippocampi of kids who had mothers that were not deemed nurturing.

The study is published online this week in the Proceedings of the National Academy of Sciences.

Decades of research have shown the importance of a nurturing caregiver -- whether it's mom, dad, grandparents or even foster parents -- on a child's emotional and behavioral development, Luby said. Rodent studies have also shown a connection between physical attributes of the brain and nurturing mothers.

"This gives us very concrete, physical evidence by showing this key region of the brain is healthier and more well-developed in children who receive this rich nurturance," Luby said.

In the study, researchers excluded children who had depression or other psychiatric disorders that could influence the size of the hippocampus.

Robert Myers, an assistant clinical professor of psychiatry and human behavior at University of California, Irvine School of Medicine, said the study is a "confirmation of facts related to brain development and plasticity that have been known since the late 1990s."

And Myers added, "This study shows that aspects of the early psycho-social environment can impact structural aspects of the brain."

Yet, there are lots of stressors for today's parents that can make it difficult to be as nurturing as they'd like to be. Time pressures, financial stress and single parenting can all make it more difficult, he said.

If moms are struggling, they should reach out to family, friends, their church or seek professional counseling, Myers added.

"Holding your child, helping them learn to soothe themselves, or making time to have fun, positive time with kids, even 15 to 20 minutes a day, keeps that bond strong," Myers said.

And moms shouldn't be too hard on themselves either. Occasionally losing patience and snapping at your children won't cause their hippocampus to shrink.

Brains develop over years and years, so it's the overall quality of the parent-child relationship that matters, he added.

"We all have bad days. Even child psychologists yell at their kids once in awhile," he said.

More information

Nemours has more on how parents can help their children learn to control their emotions and cope with frustration.