Brain Power 
Implanted electrodes could aid paralyzed patients
From: Technology Review, April 2002 - page 20
By: Rebecca Zacks

In a small lab at Brown University in Providence, RI, a rhesus macaque sits
in a chair facing a computer screen, gripping the handle of a device that
looks a lot like a sailboat's tiller. For the moment, the monkey uses this
device as if it were a computer joystick to control a simple video game: a
colored dot appears on the screen, and the animal moves the cursor to meet
it. Once the animal gets good at the task, though, the researchers in the
adjoining room will flip a switch and it will be signals straight from the
monkey's brain, not the joystick's movements, that drive the cursor. 

This eerie feat is possible because the researchers, led by Brown
neuroscientist John Donoghue, have implanted a tiny array of electrodes in
the monkey’s brain. The electrodes intercept signals from individual neurons
in the brain, and a specially developed computer algorithm translates these
signals into trajectories and velocities for the computer cursor. The
researchers' ambitions, however, extend way beyond video-game-playing
monkeys. Their hope is that their brain-machine interface system will give
patients paralyzed by spinal-cord injuries or neurodegenerative diseases new
abilities to interact with the world around them - using nothing more than
the power of their thoughts. 

Caption: Cyberkinetics uses brain signals picked up by this
four-millimeter-square array of electrodes to control a computer or a robotic
arm. 

http://www.technologyreview.com/articles/innovation10402.asp