Central Nervous System Underpinnings of Sensory Hypersensitivity in Migraine: Insights from Neuroimaging and Electrophysiological Studies

Abstract

Whereas considerable data have been generated about the pathophysiology of pain processing during migraine attacks, relatively little is known about the neural basis of sensory hypersensitivity. In migraine, the term "hypersensitivity" encompasses different and probably distinct pathophysiological aspects of sensory sensitivity. During attacks, many patients have enhanced sensitivity to visual, auditory and/or olfactory stimuli, which can enhance headache while interictally, migraineurs often report abnormal sensitivity to environmental stimuli that can cause nonpainful discomfort. In addition, sensorial stimuli can influence and trigger the onset of migraine attacks. The pathophysiological mechanisms and the origin of such sensitivity (individual predisposition to develop migraine disease or consequence of repeated migraine attacks) are ill understood. Functional neuroimaging and electrophysiological studies allow for noninvasive measures of neuronal responses to external stimuli and have contributed to our understanding of mechanisms underlying sensory hypersensitivity in migraine. The purpose of this review is to present pivotal neuroimaging and neurophysiological studies that explored the basal state of brain responsiveness to sensory stimuli in migraineurs, the alterations in habituation and attention to sensory inputs, the fluctuations of responsiveness to sensory stimuli before and during migraine attacks, and the relations between sensory hypersensitivity and clinical sensory complaints.

Brain Diffusion Abnormalities in Children with Tension-Type and Migraine-Type Headaches

“…These regions are involved with both pain nociception circuitry and the limbic system, which has been previously implicated in the perception of pain in adult patients with MTH at the functional, mechanistic, and electrophysiologic levels. 16,17 The involvement of TTH abnormalities, which was unexpected, indicates that diffusion abnormalities in the hippocampus and thalamus may potentially reflect enhanced pain circuitry as opposed to intrinsic pathophysiologic differences between MTH and TTH. This study is the first to describe early ADC diffusion changes in several areas involved in the limbic circuit in pediatric patients with MTH and TTH.…”

Sensory Hypersensitivity Symptoms in Migraine With vs Without Aura: Results From the American Registry for Migraine Research

“…Patients with migraine also commonly experience photophobia, phonophobia, and CA between attacks and demonstrate lower discomfort thresholds to visual, auditory, and tactile stimuli in the interictal period compared to non‐migraine controls . Functional neuroimaging studies have found that people with migraine have greater response to visual stimuli in the visual cortex and in visual association areas, and it is believed that this brain hyper‐responsiveness may relate to symptoms of photophobia . Interictal photosensitivity in patients with migraine is associated with brain structural aberrations, including greater cortical thickness in the left fronto‐parietal and right parietal‐occipital regions .…”

“…Patients with migraine also demonstrate increased interictal connectivity between auditory and visual cortices and the anterior insula, which is involved in emotional salience; this may in part explain the heightened sensitivity to visual and auditory stimuli in migraine . CA, another form of sensory hypersensitivity, is likely related to sensitization of pain processing and modulating regions including first‐order and second‐order trigeminovascular neurons and thalamic nociceptive neurons …”

“…[10][11][12] Functional neuroimaging studies have found that people with migraine have greater response to visual stimuli in the visual cortex and in visual association areas, and it is believed that this brain hyper-responsiveness may relate to symptoms of photophobia. 13 Interictal photosensitivity in patients with migraine is associated with brain structural aberrations, including greater cortical thickness in the left fronto-parietal and right parietal-occipital regions. 14 Patients with migraine also demonstrate increased interictal connectivity between auditory and visual cortices and the anterior insula, which is involved in emotional salience; this may in part explain the heightened sensitivity to visual and auditory stimuli in migraine.…”

“…15 CA, another form of sensory hypersensitivity, is likely related to sensitization of pain processing and modulating regions including first-order and second-order trigeminovascular neurons and thalamic nociceptive neurons. 13,16,17 About one third of patients with migraine experience an aura with at least some of their migraine attacks. 18 Several neuroimaging studies have shown increased interictal stimulus-induced activation of the visual cortex and increased visual network connectivity in migraine with aura (MwA) compared to migraine without aura (MwoA).…”