Reported visual imagery and apparent motion: an event-related potential study.

A previous behavioral study showed that a group of individuals with high vividness of visual imagery (High group), as determined from the score for the Vividness of Visual Imagery Questionnaire (VVIQ), could perceive the apparent motion path more strongly than a group of individuals with low vividness of visual imagery (Low group). To examine the physiological differences underlying these differences in perception, we compared the brain activity during an apparent motion task for the High and the Low groups using electroencephalography. We initially screened 60 potential participants using the VVIQ. On the basis of their scores, we invited 20 people from the lower and the higher ends of the VVIQ distribution to participate in our event-related potential study. Our results showed that individuals in both the High and the Low groups were sensitive to the apparent motion content of the task. Perception of apparent motion evoked a negative potential starting around 90 ms, followed by a positive potential beginning at 150-170 ms after the second stimulus. The scalp distributions of both negative and positive potentials for the High group were broader than those for the Low group. Moreover, the onset of positivity in the High group (150 ms) was earlier than that in the Low group (170 ms). We believe that these results may be mechanistically associated with the differences in the perception of apparent motion between individuals with high and low vividness of visual imagery.