A computer chip that helps you move a prosthetic arm just by thinking about it

A great deal of science aimed at improving the mobility of people with severe brain injuries has finally reached the final stage of development before it can be tried in humans. One of the most exciting gizmos coming up through this pipeline is the so called "brain-machine interface". This device consists of multiple small "electrodes" (wires that receive electrical impulses) which are implanted into the brain in the form of a special tiny microchip, which in turn is connected to a computer.

The computer identifies the pattern of electrical signals that is generated in the brain when a person thinks about performing a certain task, such as, say, extending an arm in order to reach for something. This pattern of electrical signals is similar every time the same task is performed, allowing the computer to "learn" to recognize that a certain signal pattern means a certain type of movement.

Then, every time the computer recognizes the signal, it can deliver instructions to a mechanical arm capable of performing a similar movement. Cool huh!

The brain-machine interface works pretty well in monkeys, although in the long run the monkey's brain rejects the chip by surrounding it with scar tissue, and impedes its function just a few months after it is implanted. But this does not mean that the brain-machine interface is doomed to fail. There has got to be a way around this problem, and it is only a matter of time before scientists figure out the trick to fool the brain into accepting the chip.

Although the device is intended for people with spinal cord injury, some of its applications might apply for people with impaired mobility from strokes and other neurological diseases.

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