Multiple sclerosis triggers an autoimmune response that targets and damages the outer coating of the cells in the central nervous system. We explain exactly what happens each step of the way so you can better understand what's driving your symptoms. Special thanks to Lana Zhovtis Ryerson, M.D., a board certified neurologist and assistant professor in the department of neurology at NYU Grossman School of Medicine in New York City for sharing her insight and expertise for this video.