Researchers believe a recent breakthrough using a computer to bypass commands from the brain to the legs could help people with walking disabilities caused by spinal cord injuries. From wired:
Instead of employing the brain, the technique uses arm movements and a computer interface to tell the legs what to do by creating an artificial connection to the locomotion centre in the base of the spinal cord.
The gait disturbance and walking difficulties experienced by people who have suffered spinal cord injuries can be attributed to damage to the neural pathways that run to the locomotion centre. Usually when the link between the brain and locomotion centre is corrupted, the ability to walk is directly affected. The other neural pathways above and below the injury, however, usually maintain most of their functions.
While the brain sends messages to the locomotion centre about starting and stopping walking and changing speed, rhythmic movements, such as those required for swimming and walking, can be controlled even when the locomotion centre is isolated from the brain. By bypassing the need to include the brain in the equation and replacing it with a computer interface instead, walking ability is restored.
The research team from the National Institute for Physiological Sciences in Japan decided that the best way to tell the brain what to do would be by mirroring the action of the arm muscles, which are obviously in most circumstances strongly associated with leg movement. In the testing phase of the theory, participants — all of whom it should be noted did not suffer with neurological problems — could control a magnetic stimulator capable of driving the spinal locomotion centre non-invasively. They were asked to relax their legs but move their arms. The results were that they were able to control their leg behaviour, to the point of being able to manipulate their step cycle.