Cerebral blood flow in migraine with aura.

Pathognomonic changes in regional cerebral blood flow (rCBF) have gradually been described during the last decade. They support spreading cortical depression as the mechanism underlying the migraine aura but are not the direct cause of pain since they are absent in migraine without aura and are present in migraine aura without pain. Dilatation of intra- and extracranial arteries, on the other hand, takes place in both forms of migraine and seem closely associated to the pain. Dilatation and perivascular nociceptor sensitization may, very likely, be caused by neuropeptides and monoamines released from perivascular nerves and/or mast cells.