Once again, scientists are discovering new reasons why the adage that your brain cells never grow back is not entirely correct. The article below describes the recent results from Dr. Marc Tessier-Lavigne of Howard Hughes Medical Institute at Stanford University where his group fed a special molecule to a neuron and then cut it (in a rat, of course). The neuron's structures grew back after the injury giving some clues as to how we might be able to build on this technique to help humans repair a damaged nervous system.