An experimental device that connects to individual neurons in the brain has enabled monkeys to overcome wrist paralysis, a development researchers say could help people with spinal injuries.

The device monitored brain activity in two two pigtail macaque monkeys and used mobile electrodes to move and connect to the neurons where the strongest signal was coming from. These signals were then routed directly to the corresponding muscles.

Chet Moritz and colleagues at the Washington National Primate Research Center in Seattle published their findings online Wednesday in the journal Nature. They said the brain-machine interface could lead to simpler treatments for spinal cord injury, stroke and other movement-related impairments, and could lead to more natural prosthetic devices. (Listen to the Quirks & Quarks interview with the stody's lead author.)

To test the device's ability to overcome paralysis, the researchers first taught the monkeys to operate a computer cursor using wrist motions. They then temporarily paralyzed the monkeys' wrists with an anesthetic.

The device then acted as a workaround, routing control signals from the brain around the injury by artificial connections. The monkeys quickly learned to use the brain cell activity to control their wrist muscles and were able to continue playing the computer game. The researchers found it was even possible to use brain cells not normally involved in the wrist movement, a finding they say "considerably expands the source of control signals for brain-machine interfaces."

More complex movements would require monitoring multiple brain cells, the researchers said.

"There's a long ways to go, and there's no way to say with confidence that it will work," said Moritz, who added that adapting the approach for humans is years, if not decades, away from use in people.