Although the spinal cord can recover from minor damage, severe injuries, like those that cause paralysis, are permanent…right? When deep cuts partially sever rats’ spinal cords, they isolate the lower part of the spine from the brain. Since that part of the spine is responsible for controlling the rats’ hind limbs, it leaves the legs paralyzed. A team of Swiss scientists tackled the challenge of restoring the brain-to-limb connection, successfully re-teaching paraplegic rats to walk, run, and climb stairs.
First, the researchers injected the isolated section of spinal cord with neuron-exciting chemicals called neurotransmitters. Then, they used electrodes on the outside of the spinal cord to send continuous electrical signals to those excited nerve cells. This chemical and electrical stimulation acted as a sort of molecular prosthesis for the signals that would normally come from the brain but that couldn’t get past the spinal injury.