[extropy-chat] mech arm controlled via neurons

Avatar Polymorph avatar at renegadeclothing.com.au
Wed Mar 24 21:57:54 UTC 2004



Thought-controlled robotic arm may work in people, say scientists

24.03.2004
10.20am
WASHINGTON - Scientists who trained a monkey to move a mechanical arm using
thought alone say that experiments in Parkinson's disease patients show the
technique may work in humans too.

Electrodes implanted in the brains of Parkinson's disease patients
transmitted signals that might someday be used to operate remote devices,
the team at Duke University Medical Centre reported.

In 2000, Dr. Miguel Nicolelis, the neurobiologist who led the studies, made
headlines when he trained a monkey to move a robotic arm using thoughts and
electrodes implanted in her brain.

Last October, he refined the experiment, training a monkey to move the arm
without even bothering to move her own arm. It showed she consciously knew
she was controlling the device with her thoughts.

The hope is to create artificial arms and other prosthetic devices to help
severely disabled people.

The researchers are also getting funding from the Defence Advanced Research
Projects Agency, presumably with secret military applications in mind.

But experimenting on people is tricky.

Nicolelis said he and colleagues took advantage of brain surgery being done
on patients with Parkinson's disease.

These operations involve the use of deep brain stimulators that work to help
counteract the severe tremors of Parkinson's, an incurable disease marked by
the destruction of certain brain cells.

In order to find the best place to put the stimulators, surgeons at first
temporarily implanted arrays of 32 microelectrodes. The patients are awake
during surgery so they can guide the surgeon.

Nicolelis and colleagues were given five minutes to add their own
experiments to the procedure on each of 11 patients.

IDENTIFYING THE RIGHT NEURONS

They gave the patients a video game to play while the electrodes sent their
signals from within the brain. A computer had five minutes to analyse the
signals and correlate them with the hand movements used during the video
games.

"We were surprised to find that our analytical model can predict the
patients' motions quite well," said Nicolelis. "We only had five minutes of
data on each patient, during which it took a minute or two to train them to
the task."

The key is to find the individual neurons that are activated when someone
consciously thinks about a movement and then makes the movement. Studies
have shown that these brain cells remain active even in amputees.

Electrodes and the right computer program can translate the faint signals
made by each neuron into something that can be used to operate and direct a
machine such as a robotic arm.

While the monkeys had wires implanted in their skulls that were connected to
a device that controlled an external robotic arm, Nicolelis said his team
had recently designed a wireless model of electrode that worked in monkeys.

"Something like this would be implanted. It would remain in place and
continuously send activity from the brain areas," Nicolelis said in a
telephone interview.
His team will report its findings in the July issue of the journal
Neurosurgery.

Dr. David Turner, who also worked on the study, said the most obvious
application of such technology would be a robotic arm for a quadriplegic.
Another possibility his team is working on is a thought-controlled electric
wheelchair, or a keyboard that could be used by patients paralyzed by injury
or disease.

Nicolelis said his team was seeking Food and Drug Administration permission
to do more experiments on human volunteers. "As soon as we have permission
to proceed, we are building a whole apparatus," he said.

- REUTERS





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