The central nervous system (CNS) consists of the brain and spinal cord, which distributes, processes, and receives information to and from all parts of the body. MS affects the CNS.
The peripheral nervous system (PNS) collects and delivers sensory and motor information to the spinal cord. MS does not directly affect the PNS.
The frontal lobe processes many of our higher thinking or cognitive functions, such as attention and concentration. MS lesions here can cause reduced attention and concentration, as well as reduced mobility. For example, a lesion on the left side of the frontal lobe may cause reduced mobility on the right side of the body.
The optic nerve sends sensory information from what you see with your eyes to your brain. MS lesions can disrupt the flow of this information, causing blurry, reduced vision. This type of relapse symptom is called optic neuritis. There may also be pain that increases with eye movement.
The parietal lobe processes sensory information. MS lesions on the left parietal lobe can cause numbness or the feeling of pins and needles on the right side of the body.
The cerebellum plays an important role in coordinating your body movements. MS lesions here can cause symptoms like walking difficulties, lack of coordination, and loss of balance.
The brainstem plays a role in muscle movements including reflexes, facial movement and vision. MS lesions here can cause symptoms like double vision (diplopia), facial pain, and walking difficulties.
The spinal cord transfers sensory and motor information between the brain and the rest of the body. MS lesions here can cause inflammation of the spine (myelitis), a sensation of electricity travelling down your spine (L’hermitte’s sign), or bladder and bowel problems.