Zaps to Ear Make Stroll No Walk in the Park
Imagine a trip to the park. You encounter a blindfolded man with electrodes stuck to his head. Nearby is another man, holding what looks like a control box for a remote control car.
As the man fiddles with the control box joysticks, the blindfolded man sways through the park like a zombie, walking wherever he is steered.
This is what you would have seen had you stumbled across Dr. Richard Fitzpatrick at the Sydney Royal Botanic Gardens in Australia recently.
Fitzpatrick, a neurophysiologist at the Prince of Wales Medical Research Institute, wanted to see whether he could control human movement using electrical brain stimulation.
The purpose of the experiment, published Tuesday in the journal Current Biology, was to investigate the body’s balance and navigational mechanisms, and their evolutionary role in our ability to walk upright.
Fitzpatrick’s team focused on the tiny tubes in each ear called semicircular canals.
Sticking electrodes behind the ears of test subjects, the researchers delivered electrical stimulation to the nerves connecting the semicircular canals to the brain. The subjects were blindfolded because visual information would have told the brain it was being tricked.
They were then told to walk in a straight line.
The electrical signals tricked the subjects’ brains into thinking they were veering off a straight course, causing an over-correction in the opposite direction. The subjects thought they were walking straight when their course actually twisted.
The researchers also made the subjects wobble, by sending electrical signals that made them believe they were falling down.
The results showed that the semicircular canals control both balance and navigation, essential components of upright walking.
This technique could have clinical applications, such as counteracting motion sickness, Fitzpatrick said. The electrical stimulation of the semicircular canals could also be used with virtual-reality goggles to create very convincing sensations of movement -- for “games, games, games!” he said.