PATHOLOGY OF MIGRAINE PAIN AND ITS EFFECT ON SENSORY PROCESSING

Migraine is a primary headache disorder mainly affecting women that features a cyclical pattern of chronic pain attacks resulting from central sensitization of the trigeminal nervous system and various other neurovascular mechanisms to create a disease state wherein pain perception is intensely heightened, leading to this disor- der being one of the most prevalent and disabling chronic pain diseases worldwide. Migraine headaches are often triggered by environmental sensory stimuli, such as light and sound, wherein banal amounts of sensory input become noxious and in- duce migraine headache, thus suggesting that a maladaptive association between the nociceptive and sensory processing networks could be the underlying cause. Mi- graine disorder can have different subtypes based on frequency of attacks (chronic and episodic) and aura manifestation, and while under the same illness classification, differences between these subtypes exist in terms of their pathology. In terms of gen- eral migraine pathology shared among all migraine subtypes, migraine headache and its associated symptoms are the result of neural damage to cortical areas involved in nociceptive transmission (causing both the facilitation through synaptic plasticity and dysfunctional regulation of pain signals); altered functional connectivity be- tween nociceptive, sensory processing, and affective cortical networks (leading to increased awareness and perception of pain); increased production of inflammatory neuropeptides; and dysfunctional integration and processing of modality-specific sensory information (leading to the development of sensory sensitivities such as photophobia and phonophobia)