Abstract/Text: Migraine is a chronic recurrent disorder with episodic manifestations that is progressive in some individuals. Migraine progresses clinically, physiologically, and anatomically. Progression may be a consequence of the mechanisms that generate the migraine attacks (eg, cortical spreading depression) or it may be a function of the activations generated by the attacks (eg, lesions in the periaqueductal gray area), a hypothesis supported by the increase in lesions with attack frequency. Progression may also be partially explained by common genetic or environmental risk factors. Finally, migraine with aura is associated with an elevated Framingham score and with risk factors for cardiovascular disease. Research on this issue is in its infancy and cautions are necessary before extrapolating this information into clinical practice.

Abstract/Text: Cortical spreading depression (CSD) has been suggested to underlie migraine visual aura. However, it has been challenging to test this hypothesis in human cerebral cortex. Using high-field functional MRI with near-continuous recording during visual aura in three subjects, we observed blood oxygenation level-dependent (BOLD) signal changes that demonstrated at least eight characteristics of CSD, time-locked to percept/onset of the aura. Initially, a focal increase in BOLD signal (possibly reflecting vasodilation), developed within extrastriate cortex (area V3A). This BOLD change progressed contiguously and slowly (3.5 +/- 1.1 mm/min) over occipital cortex, congruent with the retinotopy of the visual percept. Following the same retinotopic progression, the BOLD signal then diminished (possibly reflecting vasoconstriction after the initial vasodilation), as did the BOLD response to visual activation. During periods with no visual stimulation, but while the subject was experiencing scintillations, BOLD signal followed the retinotopic progression of the visual percept. These data strongly suggest that an electrophysiological event such as CSD generates the aura in human visual cortex.