Help For The Paralyzed

Scientists have found a way of getting rats to control a simple robot arm through the activity of their brain cells. This discovery might be a step toward letting paralyzed people control prosthetic limbs.

In a study reported in the July issue of the journal Nature Neuroscience by scientists at the Duke University Medical Center in Durham, N.C., and elsewhere, the brain activity of rats was carefully monitored.

Six rats learned at first to press a lever to make the arm move back and forth like a windshield wiper. Then scientists implanted electrodes in the animals' brains, to detect the pattern of brain cell activity that made the animals' legs press the lever.

Finally, the scientists switched control of the arm to a device that monitored the rats' brains and moved the arm when the appropriate brain activity appeared. Four animals were able to continue controlling the arm in this way.

Recently, scientists have reported that paralyzed people can learn to use their brain waves to control the movement of a cursor on a computer screen.

Electrodes that had been implanted or placed on the scalp picked up their brain activity. By moving the cursor, the paralyzed people were able to communicate.