Normal lateral interactions, but increased contrast sensitivity, in migraine with aura.
Date:
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Shepherd et al, (2011, Cephalalgia, 31, 346-345) showed that migraine groups performed better than control groups at detecting rapidly presented targets. Furthermore, while other studies have suggested that there are greater inhibitory interactions in visual processing associated with migraine (Battista et al, 2011, Invest Ophthalmol Vis Sci, 6(4)), Shepherd et al, (2011) found no such difference. This study sought to further explore the excitatory and inhibitory interactions in migraine using a lateral masking task (Polat and Sagi, 1993, Vis Res, 33(7), 993–999), which has shown suppressive effects of nearby flankers, and facilitation by more distant flankers. Observers (28 control, 34 migraine with aura) indicated which of two intervals contained a centrally presented, vertical Gabor target of varying contrast. In separate blocks of trials, the target was presented alone, or flanked by two additional collinear, high contrast Gabors. Flanker distances varied between one and twelve wavelengths of the Gabor stimuli. Overall, contrast thresholds for the migraine group were lower than those in the control group. There was no difference in the degree of inhibition or facilitation within the migraine group. These results are consistent with the findings reported by Shepherd (2011), in showing enhanced contrast sensitivity in migraine with aura for small, rapidly presented targets, and no difference in the lateral interactions between target and mask stimuli compared with a control group.