What is multiple sclerosis? Multiple sclerosis is a chronic disease of the central nervous system. It is understood as an autoimmune disease, a condition in which the body's immune system mistakenly attacks normal tissues. In multiple sclerosis, the patient's cells and antibodies attack the fatty myelin sheath that protects and insulates nerve fibers in the brain and spinal cord, the two components of the central nervous system. This ultimately causes damage to the nerve cells and without the insulation provided by the myelin sheath, nerve communication is disrupted. Therefore, multiple sclerosis is characterized by symptoms that reflect the involvement of the central nervous system (Luzzio, 2014). Symptoms of Multiple Sclerosis Patients are presented with multiple sclerosis in various different forms and experience symptoms of varying degrees: mild, moderate or severe. While some patients experience predominantly emotional or cognitive dysfunction, others may experience loss of muscle control and/or visual, balance, and sensory symptoms. Other symptoms include fatigue, bladder and bowel problems. What are the causes of multiple sclerosis? The cause of multiple sclerosis is unknown. Some scientists believe that genetic factors and a person's environment play a key role in determining which people are most susceptible to developing the disease. Neuropathological changes and associated functional correlates in different subtypes of multiple sclerosis Multiple sclerosis has been classified into four different subtypes based on the distinct neuropathological changes that accompany the disease (Antony, DesLauriers, Bhat, Ellestad & Power, 2011). Relapsing-remitting form of multiple sclerosis (RRMS) Most patients with Multi...... half of the document .. .... resulting in damage to the central nervous system. The first group of mice showed a pattern of central nervous system inflammation that resembled that of the most common subtype of MS, RRMS, with lesions filled with macrophages, a type of immune defense cell. The second group of mice showed deep inflammation in central nervous system tissues and the optic nerve with lesions filled with neutrophils, another type of immune cell. Both groups of mice were given antibody drugs similar to drugs developed against MS in humans. The effects were observed over time, and the results showed that some drugs inhibited the disease in the first group of mice but did not inhibit the disease in the second group. Therefore, as Mark Kroenke (2008), first author of the study and Ph.D. student of immunology at UM stated, “This is our evidence that these are truly different disease mechanisms” (Kroenke et al., 2008).