Learning to Control a Brain-Machine Interface for
Reaching and Grasping by Primates.
Monkey Think, Monkey Do Study May Help Paralyzed
By Maggie Fox, Health and Science Correspondent
Mon Oct 13,12:05 AM ET
WASHINGTON (Reuters) - Dr. Miguel Nicolelis knew he had nailed it when
the monkey stopped using her arm to play the computer game.
An implanted device had allowed the monkey to control the game using
only her thoughts, Nicolelis and colleagues report in the Public
Library of Science Biology journal on Monday.
And changes in the way the monkey's brain cells worked suggested the
brain was physically adjusting to the device, they reported in the new
online science journal.
Nicolelis hopes the device will eventually allow paralyzed patients to
regain some ability to use their upper bodies -- virtually, if not
"The monkey suddenly realized that she didn't need to move her arm at
all," Nicolelis said in a statement.
"Her arm muscles went completely quiet, she kept the arm at her side
and she controlled the robot arm using only her brain and visual
Three years ago, Nicolelis and colleagues at Duke University in North
Carolina reported that they had allowed a monkey to move a robotic arm
using only her thoughts and implanted electrodes. But the monkey
continued to move her arm.
In the latest experiment, they said two monkeys figured out what was
happening and played a computer game using thoughts alone.
Nicolelis and colleagues first implanted microelectrodes -- each
smaller than the diameter of a human hair -- into the brains of two
female rhesus macaque monkeys named Aurora and Ivy.
One got 96 electrodes in her frontal and parietal lobes -- known to be
the source of commands for muscular movement. The second monkey got
The electrodes transmit faint signals to a computer system the
researchers have developed to recognize patterns of signals that
represent particular movements by an animal's arm. These signals are
translated and in turn control a robotic arm.
At first the animals were taught to use a joystick to control the
cursor of a video game -- which Nicolelis said they enjoyed
playing. The researchers recorded and analyzed the electrical activity
of the neurons near the implanted electrodes.
As the game became more complex, the monkeys learned how to control
The group has started working with a small group of human patients,
but Nicolelis said he could not give any details yet.
In Pioneering Study, Monkey Think, Robot Do
By SANDRA BLAKESLEE
Published: October 13, 2003
Dr. Nicolelis implanted tiny probes called microwires into several
brain regions of two rhesus monkeys. At first, each monkey learned to
move a joystick that controlled a cursor on a computer screen. When a
ball appeared, the animal had to move the cursor to the target to earn
a drink of juice. Researchers collected electrical patterns from the
monkey's brain as it performed the tasks.
After the monkey became skilled at the exercise, the scientists
disconnected the joystick. At first, the monkey jiggled the stick and
stared at the screen, Dr. Nicolelis said. Even though the joystick was
not working, the monkey's reaching and grasping motor plans were being
sent to a computer, which translated those signals into movements on
There was an "incredible moment" when the monkey realized that it
could guide the cursor and grasp an object on the screen just by
thinking it, Dr. Nicolelis said. The arm dropped. Muscles no longer
The final step was to divert brain signals to a computer model that
controlled the movements of a robot. The monkey continued to think the
movements but in doing so it now moved the robot arm directly, without
a joystick, which in turn directed movements of the cursor.
Controlling a shaky, jerky robot with thought is not easy,
Dr. Nicolelis said. When the robot is first added, the monkey's
performance degrades. It takes two days for the animal to learn the
mechanical properties of the arm and to incorporate its delays into
motor planning areas.
"By the end of training, I would say that these monkeys sensed they
were reaching and grasping with their own arms instead of the robot
arm," Dr. Nicolelis said. "Every time we use a tool to interact with
our environment, such as a computer mouse, car or glasses, our brain
assimilates properties of the tool into neuronal space. Tools are
appendages which are incorporated into our body schema. As we develop
new tools, we reshape our brains," he said.
Monkeys Control Robotic Arm With Brain Implants
By Rick Weiss
Washington Post Staff Writer
Monday, October 13, 2003; Page A01
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
"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 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.
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.
"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.
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.
Mind Control: TT&P ==> http://www.datafilter.com/mc
Home page: http://www.datafilter.com/alb