Multiple sclerosis. Fluorescence light micrograph of a section through brain tissue from a person suffering from multiple sclerosis (MS). In healthy tissue, nerves are surrounded and protected by a substance called myelin. This is destroyed in MS. Here, damaged areas (plaques) are seen (blue), with nerve tissue yellow. Loss of myelin makes the nerves unable to conduct signals properly. This leads to a variety of symptoms, including numbness, weakness and incontinence. The severity varies from person to person; some are bedridden and die within a few years, and some apparently recover. There is no cure for MS. Magnification unknown.