[Below is the original script. But a few changes may have been made during the recording of this audio podcast.]
Studies have shown that monkeys can control robotic arms and computer cursors with the electrical impulses of their own thoughts. So we know there's a way to turn the activity of neurons into a signal that can control movement of a mechanical object—but what about movement in actual muscle?
A report in the journal Nature shows that it is indeed possible to route a brain signal via an artificial connection to move paralyzed muscles.
The work was done with monkeys. Researchers recorded electrical activity in a monkey's brain as it moved a computer cursor, after which they used a nerve block to temporarily paralyze the monkey's wrists so it couldn't manipulate the cursor. They then created a new electronic connection from a single neuron to the wrist muscles. This detour bypassed the anaesthetized nerves that caused the temporary paralysis.
Within minutes monkeys started using their wrist muscles again to play a video game.
The researchers noted that the neurons used in the detour are not normally associated with wrist movement. They said that nearly any motor cortex cell can be "trained" to control any muscle.
Human clinical studies are still a long way off, but this proof of concept provides hope for the hundreds of thousands of people immobilized from spinal cord injuries or strokes.