Scientists used to believe that the brain stopped making new brain cells past a certain age. But that believe changed in the late 1990’s as a result of several studies which were performed on mice at the Salk Institute.
After conducting maze tests, neuroscientist Fred H. Gage and his colleagues examined brain samples collected from mice. What they found challenged long standing believes held about neurogenesis, or the creation of new neurons.
To their astonishment, they discovered that the mice were creating new neurons. Their brains were regenerating themselves.
All of the mice showed evidence of neurogenesis but the brains of the athletic mice showed even more.
These mice, the ones that scampered on running wheels, were producing two to three times as many new neurons as the mice that didn’t exercise.
The difference between the mice who performed well on the maze tests and those that floundered was exercise.
That’s great for the mice, but what about humans?
To find out if neurogensis occurred in adult humans, Gage and his colleagues obtained brain tissue from deceased cancer patients who had donated their bodies to research. While still living, these people were injected with the same type of compound used on Gage’s mice to detect new neuron growth. When Gage dyed their brain samples, he saw new neurons. Like in the mice study, they found evidence of neurogenesis – the growth of new brain cells.
From the mice study, it appears that those who exercise produce even more new brain cells than those who don’t. Several studies on humans seem to suggest the same thing.
Studies performed at both the University of Illinois at Urbana- Champaign and Columbia University in New York City have shown that exercise benefits brain function. The test subjects were given aerobic exercises such as walking for at least one hour three times a week. After 6 months they showed significant improvements in memory as measured by a word-recall test. Using fMRI scans they also showed increases in blood flow to the hippocampus (part of the brain associated with memory and learning). Scientists suspect that the blood pumping into that part of the brain was helping to produce fresh neurons.
Dr. Patricia A. Boyle and her colleagues of Rush Alzheimer’s Disease Center in Chicago found that the greater a person’s muscle strength, the lower their likelihood of being diagnosed with Alzheimer’s. The same was true for the loss of mental function that often precedes full-blown Alzheimer’s.
Neuroscientist Gage, by the way, exercises just about every day, as do most colleagues in his field. As Scott Small a neurologist at Columbia explains,
I constantly get asked at cocktail parties what someone can do to protect their mental functioning. I tell them, ‘Put down that glass and go for a run.
So if you want to grow some new brain cells and improve your brain function, go get some exercise!