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.
Over time, the monkeys improved their ability to control the avatar arms with their brain, performing better at the two-armed task. Furthermore, the animals' brains showed notable reorganization, or plasticity, over time in the brain areas from which the researchers recorded.
The findings, detailed today (Nov. 6) in the journal Science Translational Medicine, suggest the monkey brains are incorporating the avatar arms into their internal body image.