A group of monkeys have learned to control the arms of a virtual avatar using their minds.
The researchers hope this could benefit severely paralyzed patients in the future, a Duke Medicine news release reported.
The researchers recorded 500 neurons around the monkeys' brains (the most brain neurons ever recorded) in order to conduct the experiment. The team hoped to use the recordings to provide signals to brain machine-interfaces and control bimanual movements.
"Bimanual movements in our daily activities -- from typing on a keyboard to opening a can -- are critically important," senior author Miguel Nicolelis, M.D., Ph.D., professor of neurobiology at Duke University School of Medicine, said. "Future brain-machine interfaces aimed at restoring mobility in humans will have to incorporate multiple limbs to greatly benefit severely paralyzed patients."
The monkeys were trained within the virtual environment to place their on-screen hands on a specific target in order to complete a task. The primates started off using joysticks to control the digital monkey's arm movements, but were eventually able to maneuver the avatar using only their minds.
As the monkeys got better at controlling their avatars, the scientists observed "plasticity in cortical areas of their brains."
The results suggest the monkey must incorporate the avatar's arms into their own internal image of themselves.
The team observed the neural activity the primates displayed while participating in bimanual movement than simply moving one arm at a time. The researchers concluded neuronal ensembles "define the underlying physiological unit of normal motor functions" as opposed to small neural samples.
"When we looked at the properties of individual neurons, or of whole populations of cortical cells, we noticed that simply summing up the neuronal activity correlated to movements of the right and left arms did not allow us to predict what the same individual neurons or neuronal populations would do when both arms were engaged together in a bimanual task," Nicolelis said. "This finding points to an emergent brain property -- a non-linear summation -- for when both hands are engaged at once."
