During my research about my damaged hearing, (vestibular migraine ) I came across this site.
Current theories about migraine tally very closely with ideas I posted on this medical thread 10 years ago. All to do with vasoconstriction and dilation.
I postulated that the restriction needed urgent relief to stop endangering the brain. Whatever chemistry came to the rescue caused not only the dilation, but a deadening of circuitry in the visual cortex and various other places. Loss of memory is rare but repeated. Loss of feeling in some fingers often follows what must be the dilation phase. This was all unqualified speculation when I constructed the model, but now . . .
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5019886/