An electric signal can trick a monkey’s brain into believing the animal’s finger has been touched by Stephen Ornes
9:33am, October 31, 2013
G. TABOT ET AL/PNAS 2013
Touch something, and your brain knows. The hand sends signals to the brain to announce contact was made. But that feeling of touch may not require making actual contact, tests in monkeys now show. Zapping brain cells can fool the animal into thinking its finger had touched something. A person who has lost a limb or become paralyzed may need an artificial limb to complete everyday tasks. But such patients may not truly feel any objects they hold. The new findings point toward one day creating a sense of touch in those who use such artificial limbs. Psychologist Sliman Bensmaia of the University of Chicago worked on the new tests. His team’s findings appeared October 14 in the Proceedings of the National Academy of Sciences. The sense of touch is crucial to everyday tasks: People without it may have difficulty cracking an egg, lifting a cup or even turning a doorknob. That’s why restoring this sense is a major goal for designers of artificial limbs, Bensmaia told Science News. In their new study, Bensmaia and his coworkers worked with rhesus monkeys. The scientists implanted electrodes — small devices that can detect or relay an electrical signal — into the animals’ brains. Then they trained the monkeys to look in a certain direction whenever a particular finger was touched. The electrodes took notes of the animals’ brain activity during that touch. The scientists used the electrode data to identify which brain cells, called neurons, had become active. Now the scientists used the implanted electrodes to zap those same neurons. And the monkeys reacted as though their finger had been touched. In fact, it hadn’t. “We are trying to mimic natural signals in the brain,” Bensmaia explained toScience News. The monkeys couldn’t use words to tell the scientists what they had...
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