|image: Duke University|
(movie will open in a separate window)
Most people with severe spinal cord injuries have lost the ability to move
their bodies, but not the ability to imagine doing so.
As this ScienCentral News video reports, brain researchers want to turn those
thoughts into commands.
Moving robots with the mind
In November 2000, at Duke University, an owl monkey named Belle moved a robot
arm 800 miles away in a lab
at MIT with her mind.
Despite the sci-fi results, the setup used in the study seems crude two years
later. The monkey wore a cap that put 100 tiny wires in direct contact with
motor neurons in her brain. The cap was connected to a black box that recorded
the electrical signals from each neuron. The black box was cabled to a computer
running software to translate them into machine commands. The computer was attached
to a robot arm. Only the ethernet connection from the Duke computer to the MIT
computer was wireless.
Nicolelis, professor of neurobiology and biomedical engineering at Duke,
describes the now-famous
experiment, the research that led up to it, and the rapid advances since
then in an
article in Scientific American.
"The most important message is that basic science in brain research is capable
these days to make advances in the clinical arena," he says. What began with
recording the activity of single neurons in animals' brains is now leading to
the development of brain implants that will wirelessly control robotic prostheses
for paralyzed patients. Nicolelis hopes patients will be using such prostheses
within a decade.
The primates in today's experiments at Duke have tiny, harmless brain implants
that record the activity of hundreds of neurons for months to years. The electronic
apparatus, computer, and software are now contained in a wireless neurochip
implant the size of a pinky fingernail. Scientists at Duke are now shrinking
both the electrodes and the neurochips so much smaller that we would need a
microscope to show them to you instead of a TV camera.
Numbers of neurons
When Belle moved the robot arm with her mind in 2000, "only 50 to 100 neurons
randomly sampled from tens of millions were doing the needed work," wrote Nicolelis.
Experiments with rats in collaboration with John
Chapin's lab at SUNY Health Science Center in Brooklyn are zeroing in on
the number of neurons needed for much more precise control of a robot.
"Right now, we can monitor the activity of about 300 brain cells," says Nicolelis.
"We're very close to get to 500, and that's a very important landmark."
Fortunately, that number seems to be optimal for useful clinical applications.
If the number were in the millions, the electrodes would be impossibly invasive.
On the other hand, says Nicolelis, recording only tens of neurons from each
motor area wouldn't keep up with the brain's plasticity over time. Hes
betting that the optimal number of neurons will turn out to be between 500 and
A vision of the future
The Scientific American article features a sidebar
with a graphic showing how implanted neurochips might one day be designed to
move a patient's muscles. Nicolelis says that is possible in the future, but
And while mind control of robots is imminent, there are major hurdles. Nicolelis
says the devices will need to be as safe and effective as today's heart pacemakers.
"You would have to demonstrate very clearly without any doubt that this technology
would enhance the quality of life of your patients, to a point that it pays
to suffer whatever surgical or other procedures that may be required to create
a brain-machine interface." That will take many more animal experiments as well
as human clinical trials.
Will stem cells and other research into spinal cord regeneration make those
efforts obsolete? Nicolelis hopes they will one day. But he believes that before
that, neuroprostheses will have benefited millions of patients.
Nicolelis and other Duke scientists are also developing brain
pacemakers to control seizures in patients with severe epilepsy, as well
as neurochips that will give neurosurgeons a better view of how brain tissues
are responding during surgical procedures.
"If this technology and this concept proves to be feasible, there will be a
series of new developments, some of which we cannot even imagine right now,"
says Nicolelis, "because we will be gaining a new entry, a new view of how the
brain produces behavior."
Nicolelis' research group is funded by The Defense Advanced Research Projects
Agency (DARPA) Brain
Machine Interfaces Program, The
National Science Foundation, the National
Institutes of Health and Duke University.