Brain-Machine Interfaces
Source: Technology Review
January/February 2001
Belle, a nocturnal owl monkey small enough to fit
comfortably in a coat pocket, blinks her outsized eyes as a technician
plugs four connectors into sockets installed in the top of her skull.
In the next room, measurements of the electrical signals from some 90
neurons in Belle's brain pulse
across a computer screen. Recorded from four separate areas of Belle's
cerebral cortex, the signals provide a window into what her brain is
doing as she reaches to touch one of four assigned buttons to earn her
reward-a few drops of apple juice. Miguel Nicolelis, a Duke University
neurobiologist who is pioneering the use of neural implants to study
the brain, points proudly to
the captured data on the computer monitor and says: "This readout is
one of a kind in the world."
The same might be said of Nicolelis, who is a leader in
a competitive and highly significant field. Only about a half-dozen
teams around the world are pursuing the same goals: gaining a better
understanding of how the mind works and then using that knowledge to
build implant systems that would make
brain control of computers and other machines possible. Nicolelis
terms such systems "hybrid brain-machine interfaces" or HBMIs.
Recently, working with the Laboratory for Human and Machine Haptics at
MIT, he scored an important first on the HBMI front, sending signals
from individual neurons in Belle's brain to a robot, which used the
data to mimic the monkey's arm movements in
real time.
In the long run, Nicolelis predicts that HBMIs will
allow human brains to control artificial devices designed to restore
lost sensory and motor functions. Paralysis sufferers, for example,
might gain control over a motorized wheelchair or a prosthetic
arm-perhaps even regain control over
their own limbs. "Imagine," says Nicolelis, "if someone could do for
the brain what the pacemaker did for the heart." And, in much the same
way that a musician grows to feel that her instrument is a part of her
own body, Nicolelis believes the brain will prove capable of readily
assimilating human-made devices.
Ongoing experiments in other labs are showing that this
idea is credible. At Emory University, neurologist Phillip Kennedy has
helped severely paralyzed people communicate via a brain implant that
allows them to move a cursor on a computer screen (see "Mind Over
Muscles," TR March/April 2000). And
implants may also shed light on some of the brain's unresolved
mysteries. Nicolelis and other neuroscientists still know relatively
little about how the electrical and chemical signals emitted by the
brain's millions of neurons let us perceive color and smell, or give
rise to the precise movements of Brazilian soccer players-whose photos
adorn the walls of the São Paolo native's office. "We don't have a
finished model of how the
brain works," says Nicolelis. "All we have are first impressions."
Nicolelis' latest experiments, however, show that by
tapping into multiple neurons in different parts of the brain, it is
possible to glean enough information to get a general idea of what the
brain is up to. In Belle's case, it's enough information to detect the
monkey's intention of making a
specific movement a few tenths of a second before it actually happens.
And it was Nicolelis' team's success at reliably measuring tens of
neurons simultaneously over many months-previously a key technological
barrier-that enabled the remarkable demonstration with the robot arm.
Still, numerous stumbling blocks remain to be overcome
before human brains can interface reliably and comfortably with
artificial devices, making mind-controlled prosthetic limbs or
computers more than just lab curiosities. Among the key challenges is
developing electrode devices and
surgical methods that will allow safe, long-term recording of neuronal
activities. Nicolelis says he's begun working with Duke's biomedical
engineering department to develop a telemetry chip that would collect
and transmit data through the skull, without unwieldy sockets and
cables. And this year Nicolelis will become co-director of Duke's new
Center of Neuroengineering and Neurocomputation, which will explore
new combinations of computer science, chip design and neuroscience.
Nicolelis sees the effort as part of an impending revolution that
could eventually make HBMIs as commonplace as Palm Pilots and spawn a
whole new industry-centered around the brain.
Others in Brain-Machine Interfaces:
Organization/Project
Andy Schwartz (Arizona State University) -
Neural control of robotic arm
Antonio Regalado is Senior Editor at Technology
Review.
By Antonio Regalado
http://www.techreview.com/articles/jan01/tr10_nicolelis_printable.html
John Donoghue (Brown University) - Brain representation of
movement
Richard Andersen (Caltech) - Improved neuroelectrode systems
Phillip Kennedy, Roy Bakay (Emory University) - Communication systems
for paralyzed patients