October 1, 2013 10:14 am
A single somersault or spin will send most people reeling, but professional ballerinas perform such dizzying movements without a hitch. Through years and years of practice, their brains become desensitized to vertigo-inducing spins, turns and leaps, a new study finds.
A ballerina’s brain accomplishes this feat by turning off some processing in the vestibular system—the part of the brain responsible for balance, The Scientist explains. Researchers recruited 29 experienced dancers and 20 people of similar ages who don’t spend their time whipping around in circles. The scientists placed their subjects in swivel chairs that acted a bit like a personalized Tilt-a-Whirl. As the chairs spun, the researchers followed their subjects’ eye movements. At the same time, the participants turned a wheel to indicate how quickly they felt like they were spinning. Scientific American explains what happened:
They were able to show that dancers had a decrease in the vestibular-ocular reflex. They moved their eyes less as they whipped around…And they also felt the turning less than controls. More importantly, the dancers sense of turning, and the vestibular-ocular reflex, were UNCOUPLED. They were not related to each other. So even though their eyes were moving in the reflex, they didn’t feel it!
The authors also use an MRI to examine and compare the density of their subjects’ grey matter in the area of the brain responsible for balance. The dancers had significantly lower grey matter, hinting at their ability to not feel dizzy. This finding, SciAm points out, is only correlational, meaning dancers may physically reshape their brains with years or training, or that the people who have a natural ability not to fall over when they spin around may be those most likely to go on to become top-of-the-line ballerinas.
The paper authors, however, believe the former explanation is the correct one, although they cannot definitively prove that. “Their brains adapt over years of training to suppress that input,” they said in a statement.
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