According to a news release from the Duke University Medical Center, monkeys have been trained to move two virtual arms utilizing their minds. Duke University researchers contend that the achievement assists efforts to form bilateral motion in brain-controlled prosthetic devices for severely paralyzed patients.

To allow the monkeys to move two virtual arms, researchers documented nearly 500 neurons from numerous areas in both cerebral hemispheres of the animals’ brains, the biggest number of neurons documented and reported to date.

Numerous people deal with sensory and motor issues as a result of spinal cord injuries. Researchers are trying to create tools to help restore their movement and sense of touch by linking their brains with assistive devices.  This technique, developed at the Duke University Center for Neuroengineering, may help achieve this goal. However, prior to this research brain-machine interfaces could only move a single prosthetic limb.

“Bimanual movements in our daily activities — from typing on a keyboard to opening a can — are critically important,” noted senior author Miguel Nicolelis, professor of neurobiology at Duke University School of Medicine, 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.”

The researchers examined large-scale cortical recordings to determine if they could offer sufficient signals to brain-machine interfaces to correctly control bimanual motions.

The animals were taught in a virtual environment within which they saw realistic avatar arms on a screen and were emboldened to position their virtual hands on specific targets in a bimanual motor task. The monkeys first figured out how to control the avatar arms utilizing a pair of joysticks, but were able to figure out how to utilize just their brain activity to move both avatar arms without moving their own arms.

As their efficiency increased over time, the researchers noticed widespread plasticity in cortical areas of their brains. These findings imply that the monkeys’ brains may add the avatar arms into their internal image of their bodies, a result recently documented by the same researchers.

The researchers also discovered that cortical regions revealed specific patterns of neuronal electrical activity during bimanual movements that varied from the neuronal activity generated for moving each arm individually.

The research implies that extremely large neuronal ensembles characterize the fundamental physiological unit of normal motor functions. Tiny neuronal samples of the cortex may be not enough to manage complex motor behaviors utilizing a brain-machine interface.

“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 added. “This finding points to an emergent brain property — a non-linear summation — for when both hands are engaged at once.”

The study’s findings are described in greater detail in the journal Science Translational Medicine.

What do you think of this achievement? Start a conversation by sharing your thoughts in the comments section.