Via EurekAlert!, more signs that nerve regrowth will become an established medical procedure not too many years from now: "Brain and spinal-cord injuries typically leave people with permanent impairment because the injured nerve fibers (axons) cannot regrow. A study [now] shows that axons can regenerate vigorously in a mouse model when a gene that suppresses natural growth factors is deleted. ... [Researchers] used genetic techniques to delete two inhibitors of a growth pathway known as the mTOR pathway in the retinal ganglion cells of mice. (These cells constitute the optic nerve, which carries visual input from the retina to the brain.) Removing this inhibition brought about vigorous growth in injured axons, but not in uninjured axons, suggesting that something about the injury itself helps trigger axon regeneration. In the new study, [researchers] used a second set of genetic techniques in mice to delete a suppressor of inflammatory signaling, known as SOCS3, in retinal ganglion cells - and again saw robust axon growth after injury. The greatest effect was seen after one week, when there were also signs that the mTOR pathway was re-activated."