Jewish World Review June 14, 2002 / 4 Tamuz, 5762
http://www.jewishworldreview.com -- Neuroscientists report they may have identified the part of the brain that distinguishes Fred Astaire and Ginger Rogers dancing types from average Joes and Janes with two left feet.
This new understanding of a brain area within the region known as the cerebellum could some day help medical researchers treat damage from such conditions as stroke and multiple sclerosis.
"There are lots of degenerative diseases that affect the cerebellum," said researcher James Ashe of the Department of Veterans Affairs Medical Center. "It's conceivable that findings like this could be used to help rehabilitate patients."
The cerebellum is the brain region that regulates motion, from playing the piano to dunking a basketball. For decades, scientists have argued over what role it plays in learning such "motor skills." The process of figuring out how to shoot a pistol, for instance, usually also involves getting better at doing so over time, so it is very difficult to distinguish the learning process from improving performance.
Ashe and his colleagues Rachael Seidler and Daniel Willingham discovered the cerebellum apparently does not contribute to learning -- but it is responsible for how well an action is done. They performed experiments in which volunteers wiggled their fingers in response to four lights flashed on a screen. Each finger they moved was determined by which light was flashed. The scientists told the subjects this was a test of response time and they needed to move as quickly as possible.
"Now in normal healthy subjects, if you do this task and you turn on the lights in a repeating sequence, the subjects seem to learn the sequence even though many of them aren't aware of it. We know that because their response time improves," Ashe told United Press International.
The researchers then modified the test by giving a different volunteer group another task to do at the same time -- in addition to moving their fingers, they had to count how many times another light turned yellow. "It was fairly rare for it to turn yellow, so they had to be vigilant," Ashe said.
With this kind of distraction, performance was poor, and magnetic brain imaging showed no change in cerebellum activity, even though learning-related activity was taking place elsewhere in the brain. When the distraction was removed and performance improved, cerebellum activity shot up.
"Their approach was not only clever but yielded very clean data," said motor learning theorist Eliot Hazeltine at NASA Ames Research Center in Moffett Field, Calif. Many prior studies have also that the cerebellum does appear critical for learning new relationships between motor commands and sensory perceptions, Hazeltine told UPI. "The trick will be to try to reconcile all of these findings."
The scientists described their findings in the June 14 issue of the journal Science.
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