Headache
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This review aims to understand the prevalence of premonitory symptoms in migraine, postulate their mechanisms, and compare these with functional imaging studies. A thorough literature review was conducted using PubMed for prevalence studies of premonitory symptoms in migraine and functional imaging studies in the premonitory phase. The majority of studies have been retrospective reporting a prevalence of 7-88% for premonitory symptoms in migraine. ⋯ Hypothalamic involvement can explain many of the premonitory symptoms. Activation of the the brainstem structures and hypothalamus before pain suggests a pivotal role of these structures in the pathogenesis of migraine. Hypersensitivity to light and occurrence of nausea in migraine is associated with activation of central brain structures involved in these pathways, and this can occur in the absence of pain.