[monkeywire] Monkeys Control Robotic Arm With Brain Implants

francisco francisco at tweakfilms.com
Mon Oct 13 13:01:42 EDT 2003


http://www.washingtonpost.com/ac2/wp-dyn/A17434- 
2003Oct12?language=printer

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Monkeys Control Robotic Arm With Brain Implants

By Rick Weiss
Washington Post Staff Writer
Monday, October 13, 2003; Page A01


Scientists in North Carolina have built a brain implant that lets  
monkeys control a robotic arm with their thoughts, marking the first  
time that mental intentions have been harnessed to move a mechanical  
object.

The technology could someday allow people with paralyzing spinal cord  
injuries to operate machines or tools with their thoughts as naturally  
as others today do with their hands. It might even allow some paralyzed  
people to move their own arms or legs again, by transmitting the  
brain's directions not to a machine but directly to the muscles in  
those latent limbs.

The brain implants could also allow scientists or soldiers to control,  
hands-free, small robots that could perform tasks in inhospitable  
environments or in war zones.

In the new experiments, monkeys with wires running from their brains to  
a robotic arm were able to use their thoughts to make the arm perform  
tasks. But before long, the scientists said, they will upgrade the  
implants so the monkeys can transmit their mental commands to machines  
wirelessly.

"It's a major advance," University of Washington neuroscientist  
Eberhard E. Fetz said of the monkey studies. "This bodes well for the  
success of brain-machine interfaces."

The experiments, led by Miguel A.L. Nicolelis of Duke University in  
Durham, N.C., and published today in the journal PLoS Biology, are the  
latest in a progression of increasingly science fiction-like studies in  
which animals -- and in a few cases people -- have learned to use the  
brain's subtle electrical signals to operate simple devices.

Until now, those achievements have been limited to "virtual" actions,  
such as making a cursor move across a computer screen, or to small  
two-dimensional actions such as flipping a little lever that is wired  
to the brain.

The new work is the first in which any animal has learned to use its  
brain to move a robotic device in all directions in space and to  
perform a mixture of interrelated movements -- such as reaching toward  
an object, grasping it and adjusting the grip strength depending on how  
heavy the object is.

"This is where you want to be," said Karen A. Moxon, a professor of  
biomedical engineering at Drexel University in Philadelphia. "It's one  
thing to be able to communicate with a video screen. But to move  
something in the physical world is a real technological feat. And  
Nicolelis has taken this work to a new level by quantifying the  
neuroscience behind it."

The device relies on tiny electrodes, each one 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 of them in the other animal's brain.

The surgeries were painstaking, taking about 10 hours, and ended with  
the pouring of a substance like dental cement over the area to  
substitute for the missing bits of skull.

The monkeys were unaffected by the surgery, Nicolelis said. But now  
they had tufts of wires protruding from their heads, which could be  
hooked up to other wires that ran through a computer and on to a large  
mechanical arm.

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 for having too  
light a grip, and they were rewarded with sips of juice when they  
performed their tasks successfully.

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, it  
became clear, 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 then sending the appropriate instructions to the mechanical arm.

At first, Nicolelis said, the monkey kept moving the joystick, not  
realizing that her own 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.

"We couldn't speak. It was dead silence," Nicolelis said. "No one  
wanted to verbalize what was happening. And she continued to do that  
for almost an hour."

At first, the animals' performance declined compared to the sessions on  
the joystick. But after just a day or so, the control was so smooth it  
seemed the animals had accepted the mechanical arm as their own.

"It's quite plausible that the perception is you're extended into the  
robot arm, or the arm is an extension of you," agreed the University of  
Washington's Fetz, a pioneer in the field of brain-controlled devices.

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 Web, but the list  
of potential applications is endless, he said. The devices may even  
allow quadriplegics to move their own 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 recently co-founded a company,  
Cyberkinetics Inc. of Foxboro, Mass., to capitalize on the technology.

Both he and Nicolelis hope to get permission from the Food and Drug  
Administration to begin experiments in people next year. Nicolelis also  
is developing a system that would transmit signals from each of the  
hundreds of brain electrodes to a portable receiver, so his monkeys --  
or human subjects -- could be free of external wires and move around  
while they turn their thoughts into mechanical actions.

"It's like multiple cellular phone lines," Nicolelis said. "As my  
mother said, 'You can dial your brain now.' "

Significant challenges remain if the technology is to find widespread  
application in people. Although earlier experiments suggest the  
electrodes are safe and able to continue functioning for three years or  
more, longer-term safety studies are needed, and implants with far more  
electrodes may be required to accomplish anything more than the  
simplest tasks.

"For something basic like grasping a cup of coffee or brushing your  
teeth, apparently you could do almost all of this with this kind of  
prosthesis," said Idan Segev, director of the center for  
neurocomputation at Hebrew University in Jerusalem. "If you were a  
pianist and had a spinal cord injury and you wanted to play Chopin  
again, then 500 neurons is not enough."

Still, Segev expressed astonishment at how much the monkeys were able  
to do with signals from only a few hundred of the brain's 100 billion  
or so nerve cells -- evidence, he said, that "the brain uses a lot of  
backup and a lot of redundancy."

That may explain one of the more interesting findings of the Duke  
experiments, he and others said: that neurons not usually involved in  
body movements, including those usually involved in sensory input  
rather than motor output, were easily recruited to help operate the  
robotic arm when electrodes were implanted there.

Asked if the monkeys seemed to mind the experiments, Nicolelis answered  
with an emphatic "No."

"If anything, they're enjoying themselves playing these games. It  
enriches their lives," he said. "You don't have to do anything to get  
these guys into their chair. They go right there. That's play time."


© 2003 The Washington Post Company
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