Excessive sensitivity to certain visual stimuli (cortical hyper-excitability) is associated with a number of neurological disorders including migraine, epilepsy, multiple sclerosis, autism and possibly dyslexia. Others show disruptive sensitivity to visual stimuli with no other obvious pathology or symptom profile (visual stress) which can extend to discomfort and nausea. We used event related potentials (EPRs) to explore the neural correlates of visual stress and headache proneness. We analysed ERPs in response to thick (0.37 c/deg), medium (3 c/deg) and thin (12 c/deg) gratings, using mass univariate analysis, considering three factors in the general population: headache proneness, visual stress and discomfort. We found relationships between ERP features and the headache and discomfort factors. Stimulus main effects were driven by the medium stimulus regardless of participant characteristics. Participants with high discomfort ratings had larger P1 components for the initial presentation of medium stimuli, suggesting initial cortical hyper-excitability that is later suppressed. The participants with high headache ratings showed atypical N1-P2 components for medium stripes relative to the other stimuli. This effect was present after only repeated stimulus presentation. These effects were also explored in the frequency domain, suggesting variations in inter-trial theta band phase coherence. Our results suggest that discomfort and headache in response to striped stimuli are related to different neural processes, however more exploration is needed to determine whether the results translate to a clinical migraine population.
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