Monkey Moves Cursor!

Discussion in 'General Science & Technology' started by Azrael, Jun 11, 2002.

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  1. Azrael Angel of Light Registered Senior Member

    This is very interesting. Using this could lead to advances in replacement limb techniques and even could lead to advances in cybernetic methods.

    Study: Monkey brains move cursor
    Technique still a long way from human use

    WASHINGTON (Reuters) -- Monkeys implanted with special electrodes moved a cursor on a computer screen just by thinking about it, and learned how to do it better with practice, scientists reported on Thursday.

    The experiment could eventually lead to the development of better prosthetic limbs for amputees and might even offer a way for paralyzed patients to move again.

    "They were able to move balls around, by thinking about it, in three-dimensional space," said Andrew Schwartz, a neural physiologist at Arizona State University who led the study.

    The new field, called neuroprosthetics, is small but active. In March, a team at Brown University in Rhode Island reported similar research in the journal Nature.

    In Schwartz's experiment, each tiny electrode was attached to a single neuron in the motor cortex, the part of the brain where movement is controlled.

    Two rhesus macaque monkeys were fitted with 50 to 100 electrodes, which consisted of minuscule wires about half the width of a human hair.

    The monkeys had been trained to play a computer game, at first using their arms, in which they had to move virtual balls around a three-dimensional virtual space.

    After the appropriate neurons were mapped, they were fitted with electrodes that sent signals to the computer. "We basically strapped the animals' arms down so they couldn't use their arms," Schwartz said.

    At first the monkeys strained to use their arms but as they learned their thoughts alone could move the cursor on the screen, they stopped trying to move.

    Writing in the journal Science, Schwartz's team said what was new in the latest experiment was the addition of a "feedback loop" that helped the monkeys, and the computers, learn how to make the virtual movements more accurate. "They learn to get better and better at this," Schwartz said.

    This means fewer electrodes are needed to achieve more precise movement.

    "Their performance is approaching that of what we can get when they move their own arms," Schwartz said.

    Monkeys feel no pain
    Schwartz said the monkeys do not feel pain from the electrodes and have been trained to work in return for a simple drink of water. "They get used to it and they work at it until they get tired. (Then) they stop working and just sit there," Schwartz said.

    Schwartz said it will be a long time before the technique can be tried out in people.

    "Right now the electrodes we are using are not really appropriate for human use," Schwartz said. "They don't work every time."

    The electrodes also cause some scarring that may eventually affect their performance.

    Although patients likely to want to try the method first may be desperate, Schwartz said regulators would not be willing to approve major brain surgery unless it was clear it was safe.

    If he were paralyzed, Schwartz said, he would overlook the risk. "If I had my druthers, I'd do it," he said.

    At least one person has. Dr. Phil Kennedy, chief executive officer of Neural Signals in Atlanta, Georgia, implanted two glass electrodes into the brain of a quadriplegic man.

    The patient was able to move a cursor across a computer screen. But it took great effort and weeks of training.
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