Researchers Demonstrate Direct, Real-Time Brain Control Of
Computer Cursor

It is the stuff of science fiction: Researchers at Brown
University have used a tiny array of electrodes to record,
interpret and reconstruct the brain activity that controls
hand movement - and they have demonstrated that thoughts
alone can move a cursor across a computer screen to hit a
target.
The research was conducted using a primate model. Three
Rhesus monkeys received brain implants similar to those used
in treating certain human Parkinson's patients.

"We substituted thought control for hand control," said John
Donoghue, chair of the Department of Neuroscience and the
project's senior researcher. "A monkey's brain - not its
hand - moved the cursor. Use of a reconstructed signal to
allow the brain to accomplish immediate, complex
goal-directed behavior has not been done before. We showed
we could build a signal that works right away, in real time.
And we can do it recording from as few as six neurons."

This work is a step toward enabling paralyzed humans to use
thoughts to control a cursor that would allow them to read
e-mail, surf the World Wide Web, or perform other functions
through a computer interface.

Eventually, the technology may help individuals who have a
spinal cord injury, Lou Gehrig's disease or muscular
dystrophy, the researchers said. The researchers hope to
apply the technology to restore some movement control in
paralyzed patients. That step would entail seeking approval
from the Food and Drug Administration. The FDA has not
approved this "instant-control brain cursor" technique for
human use.

The findings are described in the current issue of Nature.
The lead author is Mijail D. Serruya, a graduate student
enrolled in the M.D./Ph.D. program at Brown. Serruya
performed the work as part of his Ph.D. research. As a
medical student, he assists paralyzed patients. Serruya and
Donoghue conducted the research with colleagues Nicholas
Hatsopolous, a former Brown professor now at the University
of Chicago; former Brown undergraduate Liam Paninski, now at
New York University; and current Brown graduate student
Matthew Fellows.

"This implant is potentially one that is very suitable for
humans," Serruya said. "It shows enough promise that we
think it could ultimately be hooked up via a computer to a
paralyzed patient to restore that individual's interaction
with the environment. Our goal is to make sense of how the
brain plans to move a hand through space and to use that
information as a control signal for someone who is
paralyzed. We want to provide some freedom to this
individual."

The device "would work for anything you can do or you can
imagine doing by pointing and clicking," Donoghue said.
'This includes reading e-mail. Or imagine an onscreen
keyboard that someone can use to type sentences or issue
commands by pointing and clicking. We would be
extraordinarily pleased if this system could allow a patient
to become somewhat autonomous. It would restore some
independence to paralyzed patients who are cognitively
normal people unable to carry out their movement
intentions."

The research involves use of thin electrodes to record the
activity of a few neurons in the brain's motor cortex. This
area contains the cells that fire when a hand moves.
Activity of the neurons is first recorded while a cursor on
a computer screen is moved to hit a target using a
mouse-like handle.

The scientists built a series of mathematical formulas,
called linear filters, to create a model that related the
firing of the neurons to a cursor's target position. These
linear filters then allowed the researchers to reconstruct
hand trajectory from any new neural signals.

The electrode array was connected to a computer by thin
cables. While the subject played a simple pinball-like video
game, the researchers turned off the hand control and
substituted the reconstructed signal. While the primate
continued to move its hand as if playing the game, cursor
motion actually was controlled solely by brain signals
associated with moving the hand.

The subject then used its thoughts to move the cursor to
different targets for periods averaging two minutes in
length. While this instant-control brain cursor was active,
the real-time signals allowed the animal to correct wayward
cursor movements "on the fly" in order to strike the target,
the researchers said. This entire processing took place
nearly as fast as the hand responds to the brain's movement
commands.

The research suggests that subjects can use visual and other
feedback to compensate for inaccuracies in the mathematical
model - in effect, to learn how to improve the brain's
control of cursor movement, researchers said. "Our results
demonstrate that a simple mathematical approach, coupled
with a biological system, can provide effective decoding for
brain-machine interfacing, which may eventually help restore
function to neurologically impaired humans."

The work was funded in part by the National Institute of
Neurological Diseases and Stroke, the Defense Advanced
Research Projects Agency and the Burroughs Welcome
Foundation.

Last year, Donoghue, Hatsopolous and others formed a company
to transfer the technology to help patients who suffer from
injuries and neurological disorders that result in
paralysis. That firm is called Cyberkinetics.

Bob Martone
[log in to unmask]
http://www.samlink.com/~bmartone

----------------------------------------------------------------------
To sign-off Parkinsn send a message to: mailto:[log in to unmask]
In the body of the message put: signoff parkinsn