It sounds like science fiction but the prospect of controlling robot machines by thought alone has moved a step closer with a groundbreaking experiment on human volunteers.
Artificial limbs could be operatedBy Steve Connor, Science Editor
by the power of the mind
Scientists have already proved that monkeys can move a cursor on a computer screen by thought waves and now there is evidence that similar techniques could work on man.
Researchers wired up the brains of patients having surgery to investigate the use of electrical signals generated when they thought about moving a limb to control a robot arm or computer. They believe the experiment shows it is possible to develop microchip implants for the brain that would allow people to control robotic machines using mind power.
Accident victims suffering total paralysis might be able to control wheelchairs and prosthetic limbs by thinking about hand or arm movements. Also a step nearer reality is the science-fiction concept of the man-machine "cyborg" as depicted in Hollywood films such as the Terminator series.
Miguel Nicolelis from Duke University in North Carolina, who led the research, said the aim of the latest research was purely medical, such as helping victims of paralysis who cannot move their arms or legs normally.
"I can foresee applications such as controlling wheelchairs, computers and devices required for life support and the daily routine of life," Dr Nicolelis said. "Beyond that, it is difficult to debate."
The study tested 11 patients suffering from Parkinson's disease who were asked to play a computer video game lasting five minutes as they had a brain operation as part of routine treatment for their condition.
Microelectrodes were implanted into the brain of each patient to stimulate regions of the brain known to be involved in alleviating the symptoms of the disease. But the electrodes also recorded electrical signals coming from the brain.
As each patient used joysticks to control characters onscreen during the game, the scientists recorded the array of electrical signals emanating from different parts of their brain and successfully matched them to their hand movements.
The results demonstrated that it was possible to predict the particular pattern of brain signals that correspond to certain movements of a limb. The finding opens the way for these brain signals to be harnessed for controlling machines by thought alone.
Dr Nicolelis said.: "We only had five minutes of data on each patient, during which it took a minute or two to train them to the task. This suggests that as clinical testing progresses, and we use electrode arrays that are implanted for a long period of time, we could achieve a workable control system for external devices."
Last year the research team demonstrated that laboratory monkeys could be trained to move a robot arm by thought alone. Electrical signals from arrays of micro-electrodes inserted into the outer cortex of the monkey's brain directly controlled a robot arm in a nearby room.
This time the electrodes were placed deeper in the human brain, which could be more useful in controlling a robot limb.
The results will be published in the journal Neurosurgery later this year.
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The Transcranial Magnetic Stimulator
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Persistent vegetative states and neurostimulation
Addicted brains; the chemistry of pain and pleasure
Pleasure Evoked by Electrical Stimulation of the Brain