Cortical spreading depression

(Cortical) spreading depression or spreading depolarization (SD) is a wave of electrophysiological hyperactivity followed by a wave of inhibition. Spreading depolarization describes a phenomenon characterized by the appearance of depolarization waves of the neurons and neuroglia that propagates across the gray matter at a velocity of 2–5 mm/min. SD can be induced by hypoxic conditions and facilitates neuronal death in energy-compromised tissue. SD has also been implicated in migraine aura, where SD is assumed to ascend in well-nourished tissue and is typically benign in most of the cases, although it may increase the probability in migraine patients to develop a stroke.