Machine Reads Abstract Thought
Brain decoding suggests that all kinds of thinking can be used to
control prosthetic devices
By Gabe Romain Betterhumans/ 7/8/2004

Signals from brain cells involved in abstract thinking have been
decoded, an important step towards creating better prosthetic devices
for paralyzed people.

Working with monkeys, researcher Richard Andersen and colleagues at
the California Institute of Technology in Pasadena recorded signals
from neurons related to reaching movements and then decoded the
signals using a computer.

The decoded signals enabled the researchers to predict the monkeys'
arm movements in tasks in which they thought about reaching for an
item without actually doing so.

"These signals could also be rapidly manipulated to expedite the
learning that patients must undergo to use an external device," say
the researchers. "Moreover, this research suggests that all kinds of
cognitive signals can be decoded from patients."

Signal detection

Past studies on monkeys have shown that information from neurons
coding movement instructions can be used to control prosthetic
devices .

Last year, for example, it was reported that Rhesus monkeys were
taught to control and assimilate a robot arm using signals from their
brain.

To achieve this, researchers implanted an array of microelectrodes
into the frontal and parietal lobes—areas of the brain involved in
producing multiple output commands to control complex muscle
movements.

The faint signals from the electrodes can be detected and analyzed by
a computer system to recognize patterns of signals that represent
particular movements by an animal's arm. These can be translated into
similar movements of a robotic arm.

Until now, however, nobody has succeeded in tapping the messages of
higher-order neurons involved in planning and motivation.

Cracking the code

For their study, Andersen and colleagues implanted in monkeys arrays
of electrodes into areas of the brain that encode the goals of
reaching movements rather than controlling movement itself.

While the monkeys waited for a cue that told them to reach for an
icon flashing on a screen, a computer program interpreted the brain
signals recorded by the electrodes.

Once the "neuronal code" was cracked, the researchers used the
program to decipher the direction that the monkeys were planning to
reach for during trials in which they thought about reaching but
didn't actually do so.

When monkeys remained still while having thoughts that were
consistent with requested movements, they received a reward.

Practice makes perfect

At first, the program had trouble matching the monkeys' intentions to
the icon's position much more often than chance.

As the monkeys practiced thinking about reaching, however, their
neural signals became stronger, enabling the program to decode the
correct direction more frequently.

Eventually, the program could predict the intended direction of the
monkeys' reach as much as 67% of the time.

When the monkeys knew that accurately thinking about the requested
movement would yield a preferred reward, the computer's ability to
predict direction improved by as much as 21%.

Paralysis aid

Similar goal and preference information from people with paralysis
could be useful, says Andersen.

Future technologies based on this research could allow a paralyzed
person's goal-directed thoughts to be interpreted with smart
machines.

The research also suggests that other kinds of cognitive signals can
be decoded.

"For instance, recording thoughts from speech areas could alleviate
the use of more cumbersome letter boards and time-consuming spelling
programs, or recordings from emotion centers could provide an online
indication of a patient's emotional state," say the researchers.

http://www.betterhumans.com/News/news.aspx?articleID=2004-07-08-2

http://www.infowars.com/print/ps/abstract_thought.htm