Mechanisms whereby precision spectral filters reduce visual stress: an fMRI study

Introduction: Black-and-white grating patterns with 1-8 cycles per degree (cpd) can provoke visual illusions and discomfort to which individuals with migraine are particularly susceptible [1]. Because these patterns are epileptogenic [1] the susceptibility is consistent with evidence from transcranial magnetic stimulation [2] and fMRI BOLD [3] for hyperexcitability of the cerebral cortex in migraine. Precision spectral filters, individually prescribed [4], can reduce some migraine attacks [5]. We hypothesize that the precision spectral filter reduces or alters cortical activation, thereby reduces visual illusions and possibly also frequency of migraine attacks. In thi