Migraine With Aura Inducing Characteristics and Effects on the Cerebral Arteries and Blood Flow by Hypoxia

In this study the investigators will investigate the following hypothesis * that hypoxia induce migraine headache and migraine aura * the aura phase is associated with a spreading reduction in cerebral blood flow * the migraine headache is associated with dilatation of intra- and extracerebral arteries * the migraine headache is associated with changes in brain metabolism * the pre-ictal stage of a migraine attack with aura is associated with specific patterns in neural activity.