Using signals from its brain and nothing else, a monkey has activated a human-like robotic arm to feed itself. This advance is likely to spur development of prosthetics for those with spinal cord injuries and with “locked-in” conditions such as Lou Gehrig's disease, or amyotrophic lateral sclerosis.
“Our immediate goal is to make a prosthetic device for people with total paralysis,” said Andrew Schwartz of the University of Pittsburgh and co-author of the study involving the monkey.
Previously, work has focussed on using brain-machine interfaces to control cursor movements displayed on a computer screen.
Monkeys in the Schwartz lab have been trained to command cursor movements with the power of their thoughts.
“Now we are beginning to understand how the brain works using brain-machine interface technology,” said Schwartz.
“The more we understand about the brain, the better we'll be able to treat a wide range of brain disorders, everything from Parkinson's disease and paralysis to, eventually, Alzheimer's disease and perhaps even mental illness.”
This technology enabled monkeys in Schwartz's lab to move a robotic arm to feed themselves marshmallows and chunks of fruit while their own arms were restrained.
Computer software interprets signals picked up by probes as thin as human hair. They are inserted into neuronal pathways in the monkey's motor cortex, which governs voluntary movement.
The neurons' collective activity is then evaluated using software programmed with a mathematic algorithm and then sent to the arm, which carries out the actions the monkey intended to perform with its own limb.
Movements are fluid and natural, and evidence shows that the monkeys come to regard the robotic device as part of their own body.
The findings of the study have appeared in the latest issue of the journal Nature.