In Multiple sclerosis, Where does the defect occur?

Multiple sclerosis Autoimmune condition Attacks the myelin sheath in the brain and spinal cord. Layer that surrounds the nerves, protect them and help electrical signals travel from the brain to the rest of the body. Autoimmune attacks cause the myelin sheath to become inflamed in a small patches (plaques or lesions), which can be seen on an MRI Scan. These patches of inflammation can disrupt the messages travelling along the nerves.