That, the researchers believe, comes from abnormal nerve activity. Animal studies elsewhere show that electrically stimulating the trigeminal nerve, the major nerve leading from the brain to head and face, inflames the meninges. Traditional ideas on the origin of the pain looked at changes in blood flow to the head, particularly to the scalp. But Pappagallo has long suspected abnormalities in the meninges. For all the research done on migraines, the disorder remains enigmatic.
Scientists have only incomplete explanations for the overall cause.