A Step Toward Overcoming Paralysis

U.S. scientists have created a machine that allows the brain cells of paralyzed monkeys to circumvent a simulated damaged spinal cord and move muscles well enough to play a computer game. The University of Washington researchers, led by Chet Moritz and Eberhard Fetz, used a computer-controlled device to stimulate chemically immobilized muscles. Not only cells in the motor cortex - the brain area that controls movement - were investigated, but sensory cells, too. And they worked equally well. In fact, the scientists found that two-thirds of the neurons they tried could be utilized to move musculature.

"We found remarkably that nearly every neuron that we tested in the brain could be used to control this type of stimulation," Moritz said. "We also found that monkeys could learn very rapidly to control newly isolated neurons in order to stimulate their muscles."

Previous research in this area has dealt with using computers to transmit brain activity to a prosthetic arm. "The big strategy here is to work with the muscles in the intact arms instead of artificial robotic arms or other devices other people have shown can be controlled, but may not be so practical," Moritz said.

The University of Washington researchers say they have a goal of helping paralyzed humans regain the ability to eat and drink unassisted. They're focusing now on developing an implantable wireless computer interface device. But the final result could be years, or even decades, away before it's ready for human trials.