Multiple sclerosis (MS) can be pathologically defined as the presence of distributed glial scars (scleroses) in the central nervous system that must show dissemination in time (DIT) and in space (DIS) to be considered MS lesions. The scars that give the name to the condition are produced by the astrocyte cells attempting to heal old lesions. These glial scars are the remnants of previous demyelinating inflammatory lesions (encephalomyelitis disseminata) which are produced by the one or more unknown underlying processes that are characteristic of MS.