Ballet brain

Lots of things can make you dizzy. Following economists’ predictions on the direction of interest rates will make even the most firm-stomached individual feel a little disoriented. If you are over 25 a “turn” on the “tea cups” at your local fete can also leave you unsteady on your pins. Of course, spinning endlessly on the spot is one thing that is sure to induce dizziness…unless you are a ballet dancer in which case your brain has adapted to suppress sensations of dizziness.

A ballet dancer’s life is filled with chiffon, lycra, pointing, leaping, and spinning. The spinning goes under the more exotic title of the pirouette, a full spin of the body executed on the toe or the ball of the foot. Often pirouettes are performed one after another in a way that would render most people a wobbling mess. This dizziness happiness because after spinning quickly there continues to be movement in the fluid that fills the vestibular organs in the inner ear. These vestibular organs are filled with fluid and lined with tiny hairs that perceive movement in the fluid. When you stop spinning the fluid keeps moving giving you the impression that your head is still. For ballet dancers on the other hand, a pirouette is a mere aperitif to be followed by a hearty jeté, a hefty gargouillade, or a spirited arabesque. Yet unless they have had their vestibular organs drained (not a realistic option) the ballet dancer still has fluid sloshing around in there so researchers wanted to find out why a ballet dancer doesn’t just fall off the stage after a good quintuple pirouette.

To investigate this they studied female ballet dancers with an average of 16 years ballet training and compared them to female rowers of similar ages and fitness levels.

All subjects were put through a test of spinning them on a chair with the lights out. The researchers then measured the subjects’ eye reflexes which are triggered by input from the vestibular organs. Additionally the subjects were asked to turn a handle in time with how rapidly they felt they were spinning.

The eye reflexes and perception of spinning lasted for a shorter time in ballet dancers suggesting that as a group they had adapted to the spinning sensation. Yet, this still begs the question of how the ballet dancers do it, and the answer came when the researchers looked at MRI scans of the brains of the subjects in the study.

The scans revealed that there were significant differences in the brains of the ballet dancers when compared to the rowers.

In ballet dancers’ brains the area in the cerebellum that processes input from the vestibular organs was smaller. The area in the cerebral cortex responsible for perceptions of dizziness was also smaller. In effect, the ballet dancer’s brain suppresses dizziness signals even though the messages are still coming through from the vestibular organs. It is the biological equivalent of sticking your fingers in your ears and saying, “La, la, la, I’m not listening, I’m not listening”. It is a simple adaptive mechanism to cope with the life the dancers have chosen. The studies haven’t been done yet but one assumes that the general public have developed a similar adaptive mechanism by disconnecting their cortex from their ears when a politician speaks. It’s beautiful symmetry really because in politicians evolution has apparently disconnected their cerebral cortex from their mouth.