Research has shown that people who exercise do better on memory tests. Now a new study explains specifically what exercise does within the brain. Exercise targets a region of the brain within the hippocampus, known as the dentate gyrus, which underlies normal age-related memory decline that begins around age 30 for most adults.
This finding is significant because it was accomplished via the first-ever observation of neurogenesis, the growth of neurons, within a living brain. Using an MRI imaging technique developed at Columbia, the researchers were able to identify neurogenesis within the dentate gyrus region following exercise. Previously, researchers were only able to prove neurogenesis upon postmortem exam in animal studies.
"No previous research has systematically examined the different regions of the hippocampus and identified which region is most affected by exercise," said Scott A. Small, M.D., associate professor of neurology at Columbia University Medical Center and the study's lead author. "I, like many physicians, already encourage my patients to get active and this adds yet another reason to the long list of reasons why exercise is good for overall health."
Published in the March 12-16, 2007 early online edition of the Proceedings of the National Academy of Sciences, the finding builds upon previous research at Columbia that identified the role of the dentate gyrus region of the hippocampus in normal age-related memory decline. Additionally, Fred "Rusty" Gage, Ph.D. of the Salk Institute, a lead co-investigator on this study, had demonstrated in mice that the dentate gyrus is the one area of the brain where new neurons are generated, and that exercise improves this process. This is the first human study to emerge out of this observation.
"Our next step is to identify the exercise regimen that is most beneficial to improve cognition and reduce normal memory loss, so that physicians may be able to prescribe specific types of exercise to improve memory," said Dr. Small, who is also a research scholar at the Columbia University Taub Institute for Research on Alzheimer's Disease and the Aging Brain.