Paralyzed rats learned to walk, run and spring deftly over obstacles after they were put on a physical training regimen that included electrical and chemical stimulation of their broken spinal columns and a “robotic postural interface,” a new study reveals. The study, published Thursday in Science, suggests that for humans with spinal cord injury, the trick to regaining lost movement may lie not in regeneration of the severed spinal cord, but in inducing the brain and spinal cord to forge wholly new paths toward each other. The Swiss authors liken that process to the way that infants, their nervous systems...