Now, a new small study that was published in the journal Current Biology on Monday suggests that a good workout -- even if it's just moderate exercise -- can boost the visual cortex's ability to change for the better.
The visual cortex, where the brain receives and processes visual information from the eyes, was previously thought to be a structure that lacked plasticity (or the ability to change) and couldn't be "rewired" in adulthood, Dr. Claudia Lunghi, a neuroscientist at the University of Pisa in Italy and lead author of the study, told The Huffington Post.
"For this reason, the fact that a non-invasive manipulation such as physical activity can boost plasticity in the visual cortex is particularly surprising and particularly important," she said.
Lunghi and her co-author, Dr. Alessandro Sale, a research scientist at the National Research Council's Neuroscience Institute in Italy, measured the plasticity of 20 adults' visual cortexes by asking them to watch a movie while relaxing in a chair with one eye covered by a patch. When one eye is covered, the closed eye becomes stronger as the visual cortex attempts to compensate for the lack of visual input by boosting its strength -- this change in the closed eye's strength allows scientists to measure and test the brain's visual plasticity.
Those same participants were also asked to watch a movie while wearing the eyepatch and exercising on a stationary bike for 10-minute intervals.
The researchers found the differences in strength between the patched and unpatched eyes were much more pronounced after exercise, which suggests that working out somehow increased the visual cortex's plasticity, The New York Times reported.
The researchers noted that this effect may result from how exercise can lead to a decrease in concentrations of an inhibitory neurotransmitter in the brain called GABA, which means that as concentrations of the neurotransmitter go down, the brain's plasticity and responsiveness go up.
"We were really surprised by the findings because the level of physical activity in our protocol was really moderate and nevertheless induced a strong effect," Lunghi said.
While the researchers analyzed this short-term effect of exercise, they also noticed it lasted for at least two hours after the eye patches were removed. Lunghi said she thinks regular physical exercise could lead to an enhanced plasticity of the brain in the long term, too.
If that's so, the researchers concluded, exercise could play a key role in how treatments are developed for eye and vision conditions, such as amblyopia, commonly known as "lazy eye."
"Amblyopia can be successfully treated early in life, when the visual cortex is extremely plastic, but successful treatments are currently not available for adult patients," Lunghi said. "Our study shows that plasticity of the adult visual cortex is enhanced by physical activity, so it indicates that in combination with adequate therapy, physical exercise can be beneficial for the treatment of amblyopia, boosting the efficacy of the therapy in adult patients."
The researchers plan to test the effects of exercise in adult amblyopic patients in a future study -- and other scientists agree that more research is important.
"This elegant demonstration by Lunghi and Sale provides evidence that the benefits of exercise on brain plasticity are far reaching, and raises the question of whether exercise should be included in therapeutic regimes," Dr. Holly Bridge, who studies vision and the brain at Oxford University and was not involved in the study, told Discovery News.
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