The pathogenesis of migraine aura, like migraine, remains unclear. The probable cause of migraine aura may be cortical spreading depression (CSD) and cerebral hypoperfusion. Ion changes, activation of the trigeminal nerve and release of neuropeptides seem to be secondary to CSD during an attack of migraine aura. There are many hypotheses of migraine pathogenesis. The focal symptoms during migraine aura may be due to transient constriction of a cerebral artery and headache can result from a sterile inflammatory reaction around the walls of dilated cranial vessels. The development of aura makes a vascular origin a remote possibility, while a primary disturbance of cortical neuron function, probably CSD and activation of the trigeminovascular system, is a more reasonable explanation.