• migraine;
  • visual distortion;
  • visual activation;
  • functional MRI

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.