[Note the references to applications of the techniques to the
language areas of the brain to decode what words a person is
thinking.]
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Brain implants 'read' monkey minds
http://www.newscientist.com/news/news.jsp?id=ns99996127
19:00 08 July 04
NewScientist.com news service
Brain implants have been used to "read the minds" of monkeys to
predict what they are about to do and even how enthusiastic they are
about doing it.
It is the first time such high level cognitive brain signals have been
decoded and could ultimately lead to more natural thought-activated
prosthetic devices for people with paralysis, says Richard Andersen
project leader at the California Institute of Technology, in Pasadena,
US.
By decoding the signals from 96 electrodes in a region of the brain
just above the ear -- called the parietal cortex -- the researchers
were able to predict 67 per cent of the time where in their visual
field trained monkeys were planning to reach.
They also found that this accuracy could be improved to about 88 per
cent when the monkeys expected a reward for carrying out the task.
The team were even able to predict what sort of reward the monkeys
were expecting - whether it was juice or just plain water -- from
their brain signals.
"In the future you could apply this cognitive approach to language
areas of the brain," says Andersen. By doing so it may be possible to
decode the words someone was thinking, he says.
[...]
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Neuroscientists Demonstrate New Way to Control Prosthetic Device
with Brain Signals
http://pr.caltech.edu/media/Press_Releases/PR12553.html
PASADENA, Calif.--Another milestone has been achieved in the quest to
create prosthetic devices operated by brain activity. In the July 9
issue of the journal Science, California Institute of Technology
neuroscientists Sam Musallam, Brian Corneil, Bradley Greger, Hans
Scherberger, and Richard Andersen report on the Andersen lab's success
in getting monkeys to move the cursor on a computer screen by merely
thinking about a goal they would like to achieve, and assigning a
value to the goal.
The research holds significant promise for neural prosthetic devices,
Andersen says, because the "goal signals" from the brain will permit
paralyzed patients to operate computers, robots, motorized
wheelchairs--and perhaps someday even automobiles. The "value signals"
complement the goal signals by allowing the paralyzed patients'
preferences and motivations to be monitored continuously.
According to Musallam, the work is exciting "because it shows that a
variety of thoughts can be recorded and used to control an interface
between the brain and a machine."
The Andersen lab's new approach departs from earlier work on the
neural control of prosthetic devices in that most previous results
have relied on signals from the motor cortex of the brain used for
controlling the limb. Andersen says the new study demonstrates that
higher-level signals, also referred to as cognitive signals, emanating
from the posterior parietal cortex and the high-level premotor cortex
(both involved in higher brain functions related to movement
planning), can be decoded for control of prosthetic devices.
The study involved three monkeys that were each trained to operate a
computer cursor by merely "thinking about it," Andersen explains. "We
have him think about positioning a cursor at a particular goal
location on a computer screen, and then decode his thoughts. He thinks
about reaching there, but doesn't actually reach, and if he thinks
about it accurately, he's rewarded."
Combined with the goal task, the monkey is also told what reward to
expect for correctly performing the task. Examples of variation in the
reward are the type of juice, the size of the reward, and how often it
can be given, Andersen says. The researchers are able to predict what
each monkey expects to get if he thinks about the task in the correct
way. The monkey's expectation of the value of the reward provides a
signal that can be employed in the control of neural prosthetics.
This type of signal processing may have great value in the operation
of prosthetic devices because, once the patient's goals are decoded,
then the devices' computational system can perform the lower-level
calculations needed to run the devices. In other words, a "smart
robot" that was provided a goal signal from the brain of a patient
could use this signal to trigger the calculation of trajectory signals
for movement to be accomplished.
Since the brain signals are high-level and abstract, they are
versatile and can be used to operate a number of devices. As for the
value signals, Andersen says these might be useful in the continuous
monitoring of the patients to know their preferences and moods much
more effectively than currently possible.
"These signals could also be rapidly adjusted by changing parameters
of the task to expedite the learning that patients must do in order to
use an external device," Andersen says. "The result suggests that a
large variety of cognitive signals could be interpreted, which could
lead, for instance, to voice devices that operate by the patients'
merely thinking about the words they want to speak."
Andersen is the Boswell Professor of Neuroscience at Caltech. Musallam
and Greger are both postdoctoral fellows in biology at Caltech;
Corneil is a former researcher in Andersen's lab who is now at the
University of Western Ontario; and Scherberger, a former Caltech
researcher, is now at the Institute of Neuroinformatics in Zurich,
Switzerland.
Contact: Robert Tindol (626) 395-3631 tindol at caltech.edu
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Center for
Neuromorphic
Systems Engineering
an NSF-sponsored research center
http://www.cnse.caltech.edu/index.html
California Institute of Technology
Division of Engineering and Applied Science
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Allen Barker