Monkeys outfitted with neural implants have learned to control temporarily paralyzed muscles in their arms. So instead of controlling a robot arm with its mind, the monkey controls its own muscles that have become "disconnected" from its brain. The research, conducted by the University of Washington and the Washington National Primate Research Center, is a step forward in the development of technology that routes around a damaged spine, enabling a patient to once again manipulate paralyzed body parts. From IEEE Spectrum:
In exchange for a reward of applesauce, the monkeys had been conditioned to create just the right amount of torque in their wrists to move a cursor on a display so that it hit a target. To conduct the experiments, the researchers used anesthesia to block signals in a nerve just below the shoulder of a monkey's arm, temporarily paralyzing the rest of the limb. The brain cells that control wrist movement were still firing in response to the monkey's desire to hit the target and get the payoff, but with the neural connection shut down, the wrist remained limp. The scientists implanted electrodes into the monkey's motor cortex and fed the electrical signals they received from the monkey's brain into a computer. The computer then translated the signals into a stimulating current that was fed to electrodes implanted below the nerve block in the monkey's wrist. The monkeys were able to learn to manipulate their own brains to get their wrists moving.