Scientists have figured out how mice can regain some ability to walk after spinal cord injuries, and hope this insight can lead to a new approach to restoring function in paralysed people. The research paper, published in the journal Nature Medicine, showed that the brain and spinal cord are able to reorganize functions after a spinal cord injury to restore communication at the cellular level needed for walking. Mice given partial spinal cord injuries in the laboratory gradually were able, over a period of about eight to 10 weeks, to regain the ability to walk, although not as well as before the injury, according to the scientists. After this partial spinal cord injury, the brain and spinal cord underwent a sort of spontaneous rewiring to control walking even in the absence of the long, direct nerve highways that normally connect the brain to the walking centre in the lower spinal cord, the researchers said.
The spinal cord passes through the neck and back and contains nerves that transport messages between the brain and the rest of the body. A spinal cord injury—from a car accident, for example—can cause paralysis below the site of the injury. There is no cure for such paralysis, and many scientists have been frustrated by their failure to find one.
Spinal cord damage obstructs the pathways the brain uses to transmit messages to the nerve cells that control walking. Experts had thought the only way someone with such an injury could walk again was to somehow regrow the long nerve highways linking the brain and base of the spinal cord. But what they found in the study was that when spinal cord damage blocked direct signals from the brain, the messages were able to make detours around the injury. Rather than using the long nerve highways, the message would be transmitted over a series of shorter connections to deliver the brain’s command to move the legs.