Monkey Moves Computer Cursor
by Thoughts Alone
By E.J. Mundell
NEW YORK - It may seem like science fiction, but scientists say they have developed a technology that enables a monkey to move a cursor on a computer screen simply by thinking about it.
The breakthrough could someday help totally paralyzed, ''locked-in'' patients ``operate external devices such as a robot arm, or a computer to surf the Internet,'' explained researcher Daniella Meeker of the California Institute of Technology in Pasadena.
Meeker described her team's findings at a recent meeting of the Society for Neuroscience.
Their work focuses on a section of the primate brain known as the posterior parietal cortex. Using high-tech brain scans, the researchers determined that small clumps of cells in this region--as few as 16--were active in the formation of the desire to carry out specific body movements.
Armed with this knowledge, Meeker's group implanted sensitive electrodes in the posterior parietal cortex of a rhesus monkey trained to play a simple video game. The monkey's brain was first analyzed on high-tech MRI as it used its hand to touch dots on a touch-sensitive computer screen.
``After the monkey has done this task several times, we are able to determine, for the particular neuron, the different patterns of electrical activity when he is planning reaches in different directions,'' Meeker said.
Going one step further, her team then trained the monkey to simply think about a movement, without reaching out and touching the screen. A computer program, hooked up to the implanted electrodes, interpreted the monkey's thoughts by tracking flare-ups of brain cell activity. The computer then moved a cursor on the computer screen in accordance with the monkey's desires--left or right, up or down, wherever ``the electrical (brain) pattern tells us the monkey is planning to reach,'' according to Meeker.
``In fact,'' she said, ``we found that he became quite reluctant to move his arm to the reach command once the cursor was introduced into the game. Apparently it was easier just to think about reaching.''
Speaking with Reuters Health, Meeker said her group's work differs from previous research in that it seeks to replicate the brain-motor connection ``at the level of the first inclination to make a movement.''
She added, ``This supposes that much of the downstream function--which would be normally implemented by the rest of the brain, the spinal cord and muscles--can be relegated to intelligent machines.''
Giving completely paralyzed patients full mental control of robotic limbs or communication devices has long been a dream of those working to free such individuals from their locked-in state.
``These patients are completely paralyzed and cannot speak, yet they are fully conscious and aware,'' Meeker said. Brainstem strokes, injury to the upper spinal cord or diseases such as ALS (Lou Gehrig's disease) - condemn tens of thousands of patients to such an existence.
``Restoring even the most rudimentary communication or motor function to such patients will drastically improve their quality of life,'' she said.
Of course, roadblocks remain and the technology remains crude. Still, Meeker said her group ``can achieve over 90% accuracy'' in carrying out the simple commands the monkey has been trained to perform so far. A technology that could replicate more complex movements--such as handwriting a letter or playing games with a robot arm--could still be years or decades away.
Even more challenging are ``Terminator''-type applications that would allow the minds of healthy individuals to meld with machines--allowing drivers to ``think'' their way through traffic, for example, or granting pilots the ability to navigate the skies with their mind.
``The largest difficulty that I see with this kind of sci-fi application is the current risk that brain surgery presents,'' Meeker said. ``This kind of technology could save the life of a locked-in patient, but has the potential to kill a healthy pilot if something went wrong.''
However, several groups are currently working to develop methods of tracking brain signals without the use of surgically implanted electrodes. Such a breakthrough could lay these types of safety concerns to rest and ``revolutionize'' the field, Meeker said.
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