Pathophysiology of migraine and cluster headaches

There have been remarkable advances in the last decade in unraveling the mystery of primary headache disorders such as migraine and cluster. The vascular theory has been superseded by the neurovascular phenomenon, which seems to be the permissive triggering factor in migraine and cluster headache. This has been achieved through new imaging modalities such as positron imaging tomography (PET) and functional magnetic resonance imaging (fMRI). Prior to these imaging techniques, it was not possible to study the primary headache disorders because there was no structural basis. There is now an increasing body of evidence that the brain is primarily involved in cluster and migraine and that vessel dilation is an epiphenomenon.