Background: Migraineurs with visual aura are highly susceptible to illusions and visual distortion and are particularly sensitive to a pattern of regularly spaced parallel lines or stripes.
Purpose: To determine whether the high degree of susceptibility to illusions and visual distortion in migraineurs with aura is associated with hyperneurological activity of the occipital cortex.
Methods: In order to investigate any relationships among neuronal activity, spatial frequency of square-wave gratings, and self-described visual distortion, we investigated the neuronal and psychophysical responses to square-wave gratings in migraineurs with visual aura and in nonheadache controls.
Results: Square-wave gratings provoked various types of visual distortion and illusions and induced a hyperneuronal response in the visual cortex of migraineurs with visual aura, a response that strongly depended upon the stimulus spatial frequency.
Conclusion: The hyperneuronal activity of the occipital cortex is consistent with general cortical hyperexcitability in migraine.