Center-surround visual motion processing in migraine.

PURPOSE

It has been proposed that reduced cortical inhibition might be a key feature of migraine. Here the authors compared migraine and control group performance for two visual motion tasks in which performance was considered to reflect center-surround inhibitory processes. These tasks use the observations that healthy young observers require longer stimulus durations to detect the direction of motion of larger higher contrast stimuli, and these stimuli also elicit weaker motion aftereffect (MAE) strength. Both observations are considered to arise from center-surround inhibition.

METHODS

The authors measured stimulus duration thresholds for detecting the direction of motion of stimuli of different sizes and contrasts, and also examined motion aftereffect strength for similar stimuli presented for longer durations in 20 control participants and 30 people with migraine (15 with aura). The migraine group was assessed between migraines while they were asymptomatic.

RESULTS

For the motion direction task, a significant interaction existed between experimental group and contrast for large stimuli (F((3.96, 190.01)) = 2.95; P < 0.05); however, the interaction was in the opposite direction from that expected from reduced inhibition. Similarly, the MAE data demonstrated a significant interaction between stimulus size and group, but it was in the opposite direction from that predicted (F((1, 48)) = 4.13; P < 0.05).

CONCLUSIONS

Consistent with previous studies, the migraine group in this study demonstrated abnormal visual motion processing. However, the data from both the motion direction detection and the motion aftereffect tasks do not support a theory of reduced cortical inhibition.