Brain interface lets one monkey control the movements of anotherS

Neuroscientists have taken us one step closer to an Avatar-like world after demonstrating a brain-to-spinal-cord interface that allowed a "master" monkey to remotely control the hand movement of an "avatar" monkey who was completely unconscious.

Scientists have already developed brain-to-brain interfaces, but this is the first demonstration of a brain-to-spinal-cord interface. The breakthrough could eventually allow a paralyzed person to regain control over their muscles by directly bypassing the injury in their spinal cord.

The Master and the Avatar

To make it work, scientists at the Harvard Medical School implanted a chip in a "master" monkey's brain in order to record the activity of some 100 neurons. While the monkey moved, its physical actions were mapped against patterns of electrical activity in the neurons (it's a tedious trial-and-error process, but it's the only way it can currently be done).

For ethical reasons, the "avatar" monkey was not made to be paralyzed and was instead given a strong sedative. The scientists implanted 36 electrodes in its spinal cord, followed by tests to see how different stimulations of these electrodes could affect its movement.

During the experiment, the two monkeys were hooked up such that the brain scans of the master could control the avatar's movements in real time. The avatar monkey, though unconscious, had its hand attached to a joystick.

The master monkey was then coaxed to think about moving its partner's hand in and up and down motion in order to direct a computer cursor to a target — which it was able to do 98% of the time.

Direct to Spinal Cord

The experiment successfully demonstrated that it's possible to control the movement of a limb without having to directly stimulate muscles. Eventually, more refined versions may be designed to allow a paralyzed person to control their own movements.

But for that to work, neuroscientists will have to create something far more precise and robust. Brain waves — particularly across a section of 100 neurons — are far too limited for more detailed physical applications. It may be some time before scientists will be able to achieve more than just two-dimensional up and down hand movements. In all likelihood, they'll have to develop a system that takes other neurological transmissions into account.

The other ramification of this study, of course, is the prospect of "neural coupling" — where two or more people are connected via brain interfaces (again, we're talking about something significantly more powerful). This would allow people to control the movements of their partners. Applications could range from everything through to physical rehabilitation through to recreation.

Read the entire study at Nature Communications: "A cortical–spinal prosthesis for targeted limb movement in paralysed primate avatars."