THURSDAY, June 13, 2002 (HealthDayNews) -- If you've ever wondered what sets prima ballerinas apart from everyone else, researchers from the University of Minnesota may have an answer for you -- the cerebellum.
Scientists have long known that the cerebellum is the part of the brain responsible for movement control, according to one of the new study's authors, Dr. James Ashe, an associate professor of neuroscience. But no one knew for sure whether the cerebellum was involved in learning movements or simply in performing them.
In tomorrow's issue of Science, the University of Minnesota researchers report that they've found that the cerebellum is not involved in learning movement tasks. But it is responsible for enhancing performance, which among other things, could explain why some people don't dance well, even if they know all the steps.
"[The cerebellum] seems to be important for implementing the skills that we've already learned," says Ashe.
Ashe and his colleagues asked volunteers to perform a simple task -- move their fingers in response to a light that appeared periodically on a screen. In the past, researchers have found that if they flashed such lights in a deliberate sequence, the people being tested eventually learned the sequencing after repeating it several hundred times, though they may not have even been aware they'd learned it.
The Minnesota researchers also asked the participants to do a second task -- monitor how often they saw a change in color of a square that was also on the screen -- at the same time they performed the first task. Later, they were asked to do the first task alone.
During both testing periods, the researchers measured brain activity using functional magnetic resonance imaging.
When performing both tests together, the study volunteers did poorly, suggesting that they weren't able to learn the sequence when doing two tasks at once. The functional imaging showed no changes in activity in the cerebellum during the first test of both tasks.
But when later asked to perform the sequencing test alone, the researchers discovered that the participants had, in fact, learned the light sequence and their performance greatly improved. During this test, cerebellar activity increased significantly, according to Ashe.
He says this suggests that the function of the cerebellum is more related to a change in performance than to learning movements.
Dr. Jay Van Gerpen, a neurologist from the Ochsner Clinic Foundation in New Orleans, says this study is intriguing and challenges the conventional wisdom he learned in medical school that says the cerebellum is intricately linked with learning motor behavior. From this study, it appears that "other parts of the brain learn and the cerebellum acts as a filter and modifies these movements to make them smooth," he says.
Van Gerpen likens the cerebellum to the tracking system on a missile. It helps you hone in on a target, but doesn't initiate the propulsion.
What To Do
For more information on the cerebellum, visit this Iowa State University site. The cerebellum is also the part of the brain that makes it impossible to tickle yourself. Read why at HowStuffWorks.com.
