Controlling Devices By Thought Alone

From: J. R. Molloy (
Date: Thu Nov 29 2001 - 04:48:23 MST

Electrical signals from the parietal reach region (PRR), the part of the brain
responsible for planning arm movements, can be used to control the movement of
a cursor on a computer screen. Using signals from an electrode implanted in
the PRR of a monkey, the researchers were able to mimic the animal's arm
movements with the movements of a cursor called a prosthetic icon. Eventually,
the monkey was able to control the icon by thought alone.

Previous studies have shown that the brain cells responsible for moving an arm
also can be used to control robotic arms, computer cursors or other devices.
But this study is the first to show that the cells responsible for planning
those movements can do the same.

"The key difference between our approach and the approach of several other
groups around the country is that we're looking at neural activity that is
present before, or even without, real arm movement," says Shenoy, an assistant
professor of electrical engineering at Stanford.

The advantage of using planning cells is that they encode a simpler set of
parameters than motor cells do. Whereas motor cells generate complex signals
that control the three-dimensional path of an arm as it moves toward its
target, planning cells encode primarily two parameters: where and when to
move. Systems based on planning cells may be able to use fewer brain cells,
and thus simpler electronics, than those based on motor cells. Planning cells
also are less likely than motor cells to atrophy or change function over the
course of prolonged paralysis.

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We move into a better future in proportion as science displaces superstition.

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