Exercise Regrows the Brain

Aerobic exercise might be even better for your brain than your body.

The New York Times discusses a theory that emerged from the Salk Institute during the late nineties, adding to literature on the remarkable regenerative powers of our brains and linking it to exercise:

After conducting maze tests, the neuroscientist Fred H. Gage and his colleagues examined brain samples from the mice. Conventional wisdom had long held that animal (and human) brains weren’t malleable: after a brief window early in life, the brain could no longer grow or renew itself. The supply of neurons — the brain cells that enable us to think — was believed to be fixed almost from birth. As the cells died through aging, mental function declined. The damage couldn’t be staved off or repaired.

Gage’s mice proved otherwise. [...] All of the mice showed this vivid proof of what’s known as “neurogenesis,” or the creation of new neurons. But the brains of the athletic mice in particular showed many 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.

Neurogenesis has also been observed in the human brain. But those observations were made with the brains of dead people; does human neurogenesis link to exercise as it does with rodents? For that, rougher measurements are required, such as taking functional MRIs of people placed on a fitness regime:

But something else happened as a result of all those workouts: blood flowed at a much higher volume to a part of the brain responsible for neurogenesis. Functional M.R.I.’s showed that a portion of each person’s hippocampus received almost twice the blood volume as it did before. Scientists suspect that the blood pumping into that part of the brain was helping to produce fresh neurons.

Other studies suggest the same thing. So there you have it: excercise does a brain good.

Lobes of Steel [New York Times Play Magazine]

Early Wired coverage from back when the neurogenesis status quo was shaken here and here, and stem cell possibilities here.
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Image: Toronto Western Research Network