for National Geographic News
Scientists have developed a non-invasive brain-computer interface that enables a person to move a cursor across a computer screen just by thinking about it.
The device resembles a swimming cap riddled with electrodes, which users wear against their scalp. A computer program translates electrical signals in the brain to physical outputs, which govern the movement of a computer cursor.
The technology could enable people paralyzed by spinal cord injuries and strokes, for example, to control their brain activity in order to communicate via computer or to move mechanical devices.
Before the new finding, many researchers previously assumed that only invasive brain-computer interfaces, in which electrodes are surgically implanted into the brain, could control complex movements.
"This shows that it may not be necessary to implant electrodes to gain multi-dimensional control," said Jonathan Wolpaw, a neurologist at the New York State Department of Health's Wadsworth Center in Albany. "It brings up a new non-invasive option in brain-computer interfaces."
Wolpaw directed the study, which is reported this week in the research journal Proceedings of the National Academy of Sciences.
New Motor Skills
Of the four people who participated in the study, two had severe physical disabilities.
The subjects wore the electrode caps, which recorded electroencephalographic (EEG) activity (brain waves) from their scalp. The electrodes, small metal disks about a quarter of an inch (three-fifths of a centimeter) wide, were placed over the sensory motor part of the brain.
At first, participants learned to use their thoughts to direct a cursor on a computer screen by imagining specific actions, from running to shooting baskets.
As they became more comfortable with the technology, the subjects began to rely less on such imagery to direct the cursor. Eventually, the participants often couldn't tell what they were thinking about to move the cursor; they simply moved it.
"It becomes more like a non-muscular skill," Wolpaw said. "What we're doing is giving the brain the opportunity to develop a new motor skill."
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