 Migraines are currently thought to be caused by dysfunction of the nerves in the brain.Previously, migraines were thought to be caused by a primary problem with the blood vessels in the brain.This vascular theory, which was developed in the 20th century by Wolff, suggested that the aura in migraines is caused by constriction of intracranial vessels (vessels inside the brain), and the headache itself is caused by rebound dilation of extracranial vessels (vessels just outside the brain).