Imagine a trip to the park. You encounter a blindfolded man with electrodes stuck to his head. Nearby is another man with what looks like a remote control for a toy 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 exactly what you would have seen had you stumbled across Dr. Richard Fitzpatrick at the Sydney Botanic Gardens in Australia recently.
Fitzpatrick, a neurophysiologist at the Prince of Wales Medical Research Institute, wanted to see if he could control people’s movements using electrical brain stimulation.
The purpose of the experiment, published in August in the journal Current Biology, was to investigate the body’s balance and navigational mechanisms, and their evolutionary role in humans’ ability to walk upright.
Fitzpatrick’s team focused on the tiny tubes inside each ear called semicircular canals.
By 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 to filter out visual information that would have told the brain it was being tricked.
They were then told to walk in a straight line.
The researchers sent electrical signals that tricked the subject’s brain into thinking it was veering off a straight course, causing an overcorrection in the opposite direction.
The subjects thought they were walking straight when in reality they were walking a twisting course.
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, the two essential components of upright walking.
This technique could have clinical applications, such as to counteract motion sickness, Fitzpatrick said.
