Leao's cortical spreading depression: from experimental "artifact" to physiological principle.

Cortical spreading depression was described in 1943 by Aristides Leão, a Brazilian neurophysiologist. Initially considered to be a mysterious event as it was discovered serendipitously, its nature has become progressively better known. Cortical spreading depression is now accepted as the mechanism underlying migraine aura and has became known as either Leão's spreading depression or cortical spreading depression. Recent studies have suggested a role for Leão's cortical spreading depression in the pathogenesis and symptomatology of neurologic disorders such as transient global amnesia, head injury, and cerebrovascular diseases.