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US researchers have developed
a technology that allows monkeys to move a computer cursor with their
minds alone -- raising the possibility that a similar system could one day
help people with severe paralysis communicate and function more independently.
This stranger-than-fiction
science, in which implanted electrodes helped the monkeys' brain activity
control the computer-cursor movement, could potentially be applicable
to humans.
However, these findings only
suggest such mind-controlled machines are feasible, and any actual use
of this technology is a long way off.
The investigators first studied
the brain's electrical activity in three monkeys with electrode implants
as they moved the computer cursors with a hand-controlled device. Certain
nerve cells, or neurons, fire as the hand moves through space, and the
researchers were able to create a mathematical model that related the
firing of neurons to the cursor's position.
They found that the activity
in just a handful of neurons in the brain's motor cortex could be "decoded"
into a signal capable of moving the computer cursor via thin cables that
connect the implant to the computer.
In the experiments, the monkeys
played a simple game in which they moved the computer cursor to target
positions on the screen. At certain points the hand-control device was
turned off so that, even though the animals continued to move their hands,
their corresponding brain activity was actually moving the cursor.
A similar implant device, coupled
with computer technology, could in the future allow the severely paralyzed
to perform functions as basic to everyday life as turning lights on and
off and communicating through e-mail. It might even be possible for patients
to control robotic limbs that perform complex movements such as writing.
Nature
March 14, 2002;416:141-142
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