In a development that could someday help paralyzed people regain movement, researchers used a monkey’s brain waves to control the actions of another monkey. They published their work in Nature Communications (subscription required) today.
The team, which is based out of Harvard Medical School, placed electrodes in the master monkey’s brain and the unconscious “avatar” monkey’s spinal cord. The master’s brain waves were converted into electrical signals that stimulated different electrodes in the avatar’s spine, causing the monkey to move its body despite being unconscious.
The researchers focused on moving the avatar’s hand, which was strapped to a joystick. The master monkey could see a cursor on a screen, which was controlled by the joystick. By thinking about moving the cursor, the master caused the avatar to move the joystick.
The cursor can only move up or down at the moment, but the master monkey was able to move the avatar’s arm in the right direction 98 percent of the time.
“We are hoping to move the arm in many directions,” team lead Ziv Williams told New Scientist. “To be functionally useful, you have to have fine movements in three-dimensional space.”
Before the researchers connected the two monkeys, they prepared by training and observing the master. They taught it how to use the joystick to move the cursor and also studied what kind of brain activity was associated with what kind of physical movement. They also implanted 36 electrodes in the avatar’s spine and tested what movements they could elicit by sending a signal to each of the electrodes.
It’s possible that a more refined system could someday be implanted in patients with spinal cord industries. Unlike the brain-to-brain interface revealed by University of Washington scientists last year, the Harvard system could be used to send electrical signals directly to specific muscles or a prosthetic, bypassing the need for the spinal cord as a connection to the brain.