Monkey-Machine Interface

Researchers have shown that rhesus monkeys can control the movements of two virtual avatar arms simultaneously.

Nov 11, 2013
Abby Olena

EUREKALERT, DUKE CENTER FOR NEUROENGINEERINGParalyzed patients have used brain-machine interfaces (BMIs) to control one robotic limb at a time, but figuring out how to control two arms at once is challenging. Researchers from Duke University have now shown that rhesus monkeys are capable of performing reaching movements with two arms of an avatar simultaneously using a BMI. Their findings were published in Science Translational Medicine last week (November 6).

“No device will ever work for people unless it restores bimanual behaviors,” senior author Miguel Nicolelis, a professor of neurobiology and biomedical engineering at Duke University in Durham, North Carolina, told Science NOW. “You need to use both arms and hands for the simplest tasks.”

Nicolelis and his colleagues implanted hundreds of tiny electrodes in the brains of two rhesus monkeys, which allowed the animals to control reaching movements of an onscreen avatar. They trained the monkeys to watch the avatar from the first-person point of view. When the avatar reached for two circular targets—one for each avatar arm—simultaneously, the monkeys were rewarded with a sip of juice. One monkey learned to manipulate the avatar’s arms first by controlling joysticks, then with its mind while still using the then disconnected joysticks, and finally with solely its mind and no arm movements. The second monkey learned to move the avatar’s arms by passively watching the avatar, which would be how a paralyzed person could learn to use a BMI.

“We have high hopes, but we need to be patient,” Daofen Chen, who was not involved in the work and is the extramural research program director at the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland, told Popular Science. “Their study is a significant step forward. It could lead, eventually, to more complicated tasks,” Chen told Pop Sci. But bimanual movements are not necessarily this simple, he continued, and “brain research—it’s really a long haul.”