What causes migraine?

Migraine is a complex disorder that is not fully understood. It is thought to involve an area of the brain called the thalamus and brainstem, which processes sensation and pain arising from the head and face. Certain triggers may cause an excess of sensory input into these areas of the brain causing another set of cascading responses that produce a local inflammatory process. This further triggers activity within the blood vessels of the brain and face, muscles and other structures of the head and protective structures supporting the brain causing further pain from sensitisation. Migraine aura occurs when this cascade produces a wave of electrical activity in the brain producing visual, sensory or other phenomena. The inflammatory response and brainstem overactivity continue to “feed off” each other to perpetuate the migraine attack. These inflammatory responses are mediated by certain biochemical signalling molecules, which are targets for some of the newer anti-migraine agents including the anti-CGRP medications and botulinum toxin. Other tablet anti-migraine medications have various targets within this cascading response to potentially reduce migraine severity and frequency.