Scientists at New York University School of Medicine report in a new study that they have identified the molecular switch that turns on the production of myelin, the fatty insulation around nerve cells that ensures swift and efficient communication in the nervous system. The study, published in the September 1, 2005, issue of the journal Neuron, may provide a new avenue for treating nervous system diseases such as multiple sclerosis, which are associated with damage to myelin. A team led by James L. Salzer, M.D., Ph.D., Professor of Cell Biology and Neurology at NYU School of Medicine, identified the long-sought factor that determines whether or not nerve cells will be wrapped in thick layers of myelin, producing the biological equivalent of a jelly roll.