The device relies on tiny electrodes, each resembling a wire thinner than a human hair. After removing patches of skull from two monkeys to expose the outer surface of their brains, Nicolelis and his colleagues stuck 96 of those tiny wires about a millimeter deep in one monkey's brain and 320 in the other animal's brain.
...Then came the training, with the monkeys first learning to move the robot arm with a joystick. The arm was kept in a separate room -- "If you put a 50-kilogram robot in front of them, they get very nervous," Nicolelis said -- but the monkeys could track their progress by watching a schematic representation of the arm and its motions on a video screen.
The monkeys quickly learned how to use the joystick to make the arm reach and grasp for objects and how to adjust their grip on the joystick to vary the robotic hand's grip strength. They could see on the monitor when they missed their target or dropped it from having too light a grip, and were rewarded with sips of juice.
While the monkeys trained, a computer tracked the patterns of bioelectrical activity in the animals' brains. The computer figured out that certain patterns amounted to a command to "reach." Others meant "grasp." Gradually, the computer learned to "read" the monkeys' minds.
Then the researchers did something radical: They unplugged the joystick so the robotic arm's movements depended completely on a monkey's brain activity. In effect, the computer that had been studying the animal's neural firing patterns was now serving as an interpreter, decoding the brain signals according to what it had learned from the joystick games and sending the appropriate instructions to the mechanical arm.
At first, Nicolelis said, the monkey kept moving the joystick, not realizing her brain was now solely in charge of the arm's movements. Then, he said, an amazing thing happened.
"We're looking, and she stops moving her arm," he said, "but the cursor keeps playing the game and the robot arm is moving around." The animal was controlling the robot with its thoughts.
..."John P. Donoghue, a neuroscientist at Brown University developing a similar system, said paralyzed patients would be the first to benefit by gaining an ability to type and communicate on the Internet, but the list of potential applications is endless, he said. The devices might allow quadriplegics to move limbs again by sending signals from the brain to various muscles, leaping over the severed nerves that caused their paralysis.
'Once you have an output signal out of the brain that you can interpret, the possibilities of what you can do with those signals are immense,' said Donoghue, who cofounded a Foxborough-based company, Cyberkinetics Inc., to capitalize on the technology."
It really seems that neuro has the most exciting advances right now. Every other field is serving up incremental improvements, next-generation drugs, etc. This neuro stuff -- the TMS, these cyberkinetic implants -- is not just about extending life or even restoring function, but potentially expanding the realm of human ability.