In the latest science-fiction-come-to-life advance which may one day lead to the paralyzed being able to move at the drop of a thought, researchers have devised a system that enabled monkeys to control a computer cursor with their brain nearly as quickly as with their hands.
The nerve system specialists from Brown University in Providence, R.I., implanted a tiny array of electrodes in three Rhesus monkeys to record, review and reconstitute the cerebral activity that controls hand movement. The animals responded by tailing a target around a computer screen with a cursor guided solely by their thoughts.
The fantasy-fulfilling findings, published in the British journal Nature, inspire visions of a time when paralyzed humans might use their minds to manipulate robotic limbs, researchers said.
The new system -- centered around brain implants similar to those employed in treating some patients with Parkinson's disease -- is a step up from previous devices which have required extensive training or been confined to a limited movement repertoire, investigators said.
The latest approach enlists just a few neurons in the motor cortex region of the monkey's brain to produce the desired activity. Moreover, no period of learning was required before the monkeys could perform the sleight of hand with their thoughts, they said.
"We substituted thought control for hand control," said John Donoghue, chair of the Department of Neuroscience and the project's senior researcher. "A monkey's brain -- not its hand -- moved the cursor. Use of a reconstructed signal to allow the brain to accomplish immediate, complex, goal-directed behavior has not been done before. We showed we could build a signal that works right away, in real time. And we can do it recording from as few as six neurons."
The small numbers are impressive.
"The important issue seems to be that this group is able to control the device with such a small number of nerve cells," Sandro Mussa-Ivaldi, physiologist at Northwestern University Medical School and the Rehabilitation Institute of Chicago, said in a telephone interview.
"These findings are important because they suggest that human prosthetic devices will not require large amounts of data or lengthy training to become functional," Donoghue said.
Should the work lead to its hoped-for end, it could open up a brave new world in which the thoughts of paralyzed humans set them free to roam the Internet, surf the World Wide Web, skim e-mail or otherwise explore any area unlocked through a computer interface, scientists told United Press International. Eventually, the beneficiaries of the technology might include individuals with spinal cord injury, Lou Gehrig's disease or muscular dystrophy or even stroke survivors, they said.
"The technology would be most valuable to individuals who are 'locked in' -- those who have normal cognitive function but who lack any motor function. Tetraplegics would be next in the list, followed by paraplegics," said Richard Normann, professor of bioengineering and ophthalmology at the University of Utah who is conducting similar research.
"I would expect that human experimentation would be possible in the next year or two," he told UPI, noting that in one study "locked-in" patients have already been implanted with a system to allow them to communicate through a computer.
"Right now, we are still far from practical applications of these technologies to patients with paralysis, although people are already trying some approaches on patients," Mussa-Ivaldi cautioned. "I think there's still a lot of work ahead."
Any applications to restore movement control in immobilized individuals would require approval from the Food and Drug Administration, which has not yet given the green light for human use of the "instant-control brain cursor" technique, said lead study author Mijail Serruya, who performed the work as part of his doctoral research at Brown.
"This implant is potentially one that is very suitable for humans," he said. "It shows enough promise that we think it could ultimately be hooked up via a computer to a paralyzed patient to restore that individual's interaction with the environment. Our goal is to make sense of how the brain plans to move a hand through space and to use that information as a control signal for someone who is paralyzed. We want to provide some freedom to this individual."
The device would enable patients to point and click their way around their surroundings, Donoghue said. "This includes reading e-mail. Or imagine an onscreen keyboard that someone can use to type sentences or issue commands by pointing and clicking."
The research follows on the heels of a report by Normann and company in the journal Nature which showed that, contrary to a widespread view, the motor regions of the brain do not undergo a significant reorganization even five years after spinal cord injury.
"The two papers dovetail," suggesting that individuals with spinal cord injuries could train their thoughts to control a wheelchair, robotic arm or other devices, Normann, told UPI.
"We are entering a new era in the development of human engineered interfaces to the nervous system. These systems could provide new avenues of therapy to those with non-functioning sensory or motor systems," Normann said.
"The systems that are being considered are first generation systems, and will undergo significant refinement over the next decade or two, and, as a result, provide continuously enhanced function to those who will be implanted with these new devices."
