Although there is some understanding of the mechanism of migraine, its precise underlying causes are unknown. Extensive reviews and volumes have been published on the pathophysiology of headache and, in particular, migraine.^12-15

            According to Goadsby et. al.^{16, 17}, migraine is best understood as a primary disorder of the brain.  Migraine is a polygenetic disorder believed to have a primary problem in the abnormal function of an ion channel in the brain-stem nuclei that modulates sensory input.¹⁷  Specific gene abnormalities have been found in patients with familial hemiplegic migraine, that is a mis-sense mutation in the Alpha I subunit of the voltage-gated P/Q-type calcium channels.¹⁸  As pointed out by Goadsby¹⁶, it is likely that the aura of migraine is separate from the headache as cases of migraine with aura have been linked to the familial-hemiplegic-migraine locus.¹⁹