Abstract
Individuals with migraine exhibit heightened sensitivity to visual input that continues beyond their migraine episodes. However, the contribution of colour to visual sensitivity, and how it relates to neural activity, has largely been unexplored in migraine. Previously, it has been shown that, in non-migraineurs, patterns with greater chromaticity separation evoke greater cortical activity, even when colours were isoluminant and regardless of hue. Therefore, we examined neural responses to the same chromatic patterns in individuals with migraine to investigate if their visual sensitivity was related to chromaticity separation. Eighteen individuals with migraine (12 with aura) and 17 headache-free controls viewed pairs of colours in a horizontal grating pattern that varied in their chromaticity separation. Participants rated the gratings on how uncomfortable they were to view, while EEG was recorded. Both groups showed increased discomfort and larger N170 event-related potentials with greater chromaticity separation, which is consistent with increased cortical excitability. However, migraineurs rated gratings as being more uncomfortable (p<.01) and exhibited greater N170s overall (p<.001). There were no significant effects of the colours used. Together, this indicates that greater chromaticity separation does increase neural excitation, and that this effect is heightened in migraine, consistent with the theory that the visual cortex is hyper-excitable.