Making things happen with the mind has long been a favorite topic of science fiction.
But with new technology developed at the University of Pittsburgh School of Medicine, a rhesus monkey, with arms comfortably restrained, learned to use a robotic arm to feed itself by thinking about the action.
The monkey used the arm to grasp marshmallows and fruit and put them in its mouth. It even used the grasper, as it would its own hand, to prevent the food from falling from its lips.
In a 2004 study, Pitt researchers taught a monkey partially to use a robotic arm, but in the latest research published in the journal Nature they taught the monkey to control the arm fully with its mind.
It raises hope that people with paralysis, Parkinson's disease, Lou Gehrig's disease (amyotrophic lateral sclerosis) and even Alzheimer's disease and mental illness could use the system to feed themselves and perform other tasks.
"We intend to begin human trials within the next couple of years," said Meel Velliste, research assistant professor at Pitt's School of Medicine.
Advancing the technology required a better understanding of how thought processes work, said Andrew Schwartz, senior author and professor of neurobiology the medical school.
Computer software is used to interpret signals captured by probes the width of a human hair inserted into neuronal pathways in the motor cortex -- the portion of the brain where voluntary movement originates as electrical impulses.
Using a mathematical algorithm, the software program evaluates a small sample of neuron activity then fills it out and sends a full command to the robotic arm, which carries out actions the monkey would have performed with his own arm.
Movements were so fluid and natural that the monkey seemed to recognize the robotic device as part of its own body, Dr. Schwartz said.
"The monkey learns by first observing the movement, which activates his brain cells as if he were doing it," Dr. Schwartz said. "It's a lot like sports training, where trainers have athletes first imagine that they are performing the movements they desire."
The National Institute of Neurological Disorders and Stroke at the National Institutes of Health funded the study.
The robotic arm uses only a few degrees of motion from the shoulder and elbow. To make a full hand and fingers work -- a feat yet to be accomplished -- involves 22 degrees of freedom, adding to the complexity of developing a fully functional system.
Understanding higher orders of brain processes to think, learn and solve problems will allow researchers to direct a robotic arm to replicate what a real arm does.
"It's a big challenge," Dr. Schwartz said. "But we're working rapidly and should have something in years to come."
David Templeton can be reached at firstname.lastname@example.org or 412-263-1578.