You've heard of the monkey on your back, but what about the monkey on your brain?
The monkey that served as the master had electrodes wired into his brain, while the monkey that served as the avatar had electrodes wired into his spine. The avatar's hand was placed onto a joystick that controlled a cursor displayed on the master's screen.Planet of the Avatars?
The avatar monkey was sedated so that he had no control over his own body. Computers decoded the brain activity of the master monkey and relayed those signals to the spinal cord and muscles of the avatar monkey. This allowed the master to control the cursor by moving the hand of the avatar. The master received a reward of juice if he successfully moved the cursor onto a target.
"Probably the biggest challenge we had was having this happen in real-time," Williams said. "In theory, you can record neuronal activity any time, analyze it offline, and use those signals to stimulate the spinal cord or muscles. The trick is being able to figure out what the monkey is intending in real-time and then stimulating the spinal cord or muscles to create the desired movements."