Contemporary concepts of migraine pathogenesis.

The pathogenesis of migraine is incompletely understood. Recent discoveries have shed light on the neuronal events mediating both the aura and the headache phases of migraine, identifying a cerebral cortical origin of migraine aura, susceptibility to attacks based on cortical hyperexcitability, and headache originating in the trigeminovascular system and its central projections. Abnormal modulation of brain nociceptive systems, at first transient but becoming permanent with continuing illness and, predisposing to central sensitization, may explain the prolonged headache of the migraine attack and the shift of the migraine phenotype from episodic to chronic headache. Migraine attacks might also originate in abnormal nociceptive neuromodulator centers in the brainstem.