A neurologist is a medical doctor who specializes in treating diseases of the nervous system. The nervous system is made of two parts: the central and peripheral nervous system. It includes the brain and spinal cord. Illnesses, disorders, and injuries that involve the nervous system often require a neurologist’s management and treatment. Before they can practice, neurologists must: graduate from medical school. complete an internship. receive three years of training in a Neurology residency program.