Source of Support: None, Conflict of Interest: None
The biologic basis of migraine had remained unclear until about 15 years, but current migraine research has made some major advances to explain its mechanism. Migraine is currently conceived to originate in the brain. The trigger of an attack starts a depolarising event very similar to "spreading depression" of Leao in a brain that is already hyperexcitable. Hyperexcitability of cell membrane is perhaps genetically determined. Cortical depolarising events drive the trigeminovascular system through mechanisms that are largely hypothetical but might include a migraine generating centre in the brainstem to produce changes in the vessels of the cranium and meninges. Pain sensations carrying impulses are relayed back, first reaching the trigeminal ganglion caudalis and the trigeminal cervical complex in upper cervical cord from where they are relayed further up through various transmitting pathways to the brainstem, thalamus and the cortex where pain is finally perceived and registered.