Deficient inhibition of irrelevant visual information in migraine: A magnetoencephalography study of alpha‐band activity

OBJECTIVES/BACKGROUND: There is growing evidence that migraine is associated with attentional abnormalities, both during and between attacks, potentially affecting the cognitive processing of sensory stimulation. However, the underlying neurophysiological mechanism remains poorly understood. This study aimed to investigate whether top-down and bottom-up attentional mechanisms, as indexed by alpha- and gamma-band oscillatory activity measured with magnetoencephalography are altered in patients with episodic migraine without aura during the interictal phase. METHODS: In a cross-sectional study (conducted in 2016-2017 in Lyon area of France) with a comparison of matched groups, 19 patients with migraine without aura and 19 healthy participants performed an attentional task involving visually cued auditory targets and distracting sounds to evaluate conjointly top-down and bottom-up attention mechanisms. Magnetoencephalography was used to record anticipatory alpha activity (power increase and decrease) and distractor-induced gamma activity as markers for top-down (inhibition and facilitation) and bottom-up attention, respectively. RESULTS: Compared to healthy participants, patients with migraine exhibited a significantly less prominent alpha power increase in visual areas in anticipation of the auditory target (permutation tests, cluster significance p = 0.043), indicating a reduced inhibition of task-irrelevant visual areas. In contrast, there was no significant group difference regarding the alpha power decrease in the relevant auditory cortices in anticipation of the target (permutation tests, cluster significance, p > 0.310), nor regarding the distractor-induced gamma power increase in the ventral attention network (permutation tests, cluster significance p > 0.999). CONCLUSION: These results suggest an impairment of top-down attentional inhibitory processes in migraine, as reflected by the altered alpha modulation in the visual cortex. This relative inability to suppress irrelevant sensory information may underlie the self-reported increased distractibility and contribute to sensory disturbances in migraine.