Causes of migraine

Whenever blood vessels of the brain expand and contract improperly a migraine attack can ensue. The process can start at the back one’s brain termed occipital lobe, as blood vessels start to spasm. The resulting reduction in blood flow produces an aura that some persons suffering from migraines experience. 

Apart from vascular causes migraines can occur due to neural factors too. A migraine can occur whenever certain nerves located in the lower portion of the brain get irritated, releasing certain chemicals that produces inflammation in blood vessels and irritation in the nerves, resulting in pain.