Spreading depression and peri-infarct depolarizations. Their potential roles in migraine and stroke

Spreading depression is a fascinating phenomenon that can be provoked by ch emical, electrical or mechanical stimuli of the cortex. Spreading depressio n-like transient depolarizations are observed in the periinfarct tissue aft er focal ischemia. The reduction in electrical activity and a negative dire ct current potential shift propagating over the cortex with a rate of 2-5 m m/minute are the physiological hallmarks. It is thought that spreading depr ession and peri-infarct depolarizations might play a role in the pathogenes is of migraine and stroke. However, these events have never been detected i n humans. This paper reviews the physiological characteristics of spreading depression and peri-infarct depolarizations and discusses their potential role in migraine and stroke.