Onscreen cursor controlled by brain.

• Position: Computers

It is the stuff of science fiction: Researchers at Brown University, Providence, R.I., have used a tiny array of electrodes to record, interpret, and reconstruct the brain activity that controls hand movement, and they have demonstrated that thoughts alone can move a cursor across a computer screen to hit a target. The research was conducted using a primate model. Three Rhesus monkeys received brain implants similar to those used in treating certain human Parkinson's patients.

"We substituted thought control for hand control," explains John Donoghue, chair of the Department of Neuroscience and the project's senior researcher. "A monkey's brain--not its hand--moved the cursor. Use of a reconstructed signal to allow the brain to accomplish immediate, complex goal-directed behavior has not been done before. We showed we could build a signal that works right away, in real time. And we can do it recording from as few as six neurons."

This work is a step toward enabling paralyzed humans to use thoughts to control a cursor that would allow them to read e-mail, surf the World Wide Web, or perform other functions through a computer interface. Eventually, the technology may help individuals who have a spinal cord injury, Lou Gehrig's disease, or muscular dystrophy, the researchers indicate. They hope to apply the technology to restore some movement control in paralyzed patients. That step would entail seeking approval from the U.S. Food and Drug Administration, which has yet to sign off on this "instant-control brain cursor" technique for human use.

"This implant is potentially one that is very suitable for humans," notes graduate student Mijail Serruya, lead author of the study. "It shows enough promise that we think it could ultimately be hooked up via a computer to a paralyzed patient to restore that individual's interaction with the environment. Our goal is to make sense of how the brain plans to move a hand through space and to use that information as a control signal for someone who is paralyzed. We want to provide some freedom to this individual:'

The device "would work for...