Sci-fi authors take note: Monkeys have learned to move a pair of virtual arms directly using their brain.
The finding, which comes from the same group that recently linked two rat brains together, is the latest demonstration of efforts to record signals from the brain and use them to operate computers or prosthetic limbs. The ultimate goal of this research is to restore physical control to people who are paralyzed.
From typing on a keyboard to opening a can, life is full of movements that require two arms, neurobiologist Miguel Nicolelis, who led the research, said in a statement.
"Future brain-machine interfaces aimed at restoring mobility in humans will have to incorporate multiple limbs to greatly benefit severely paralyzed patients," said Nicolelis, of Duke University School of Medicine. [Watch video of monkeys controlling avatars]
Spinal cord injuries, stroke and neurodegenerative diseases cause millions of cases of paralysis worldwide. Although these conditions lead to damage to the connections between the brain and the muscles, the brain areas responsible for muscle movements often remain intact.
Over the past decade, researchers have made great strides in developing brain-machine interfaces to connect the mind to prosthetic devices. But until now, these systems only sought to control a single limb, the researchers said.
Monkey Arm Avatars
In the study, Nicolelis and his colleagues recorded signals from nearly 500 neurons in both hemispheres of monkey brains, using arrays of tiny electrodes implanted in movement-related areas of the cortex — the largest number of neurons recorded and reported to date, the team said.
They trained monkeys to operate a pair of avatar arms in a virtual environment, first with joysticks, and later, using their minds alone. The animals performed a virtual task requiring both arms.