A topographic electrophysiologic study of mental rotation.

Mental rotation is a task performed when subjects are requested to determine whether two stimuli presented in turn have the same shape (congruency) or a mirror-image shape (incongruency) regardless of any difference in orientation. We compared event-related potentials during mental rotation tasks with narrow and wide angular disparities between the two stimuli to identify electrophysiologic correlates of mental rotation. When angular disparity was wide, a prominent negative component arose 438 ms after the second stimulus. A statistically significant difference detected between amplitudes of the negative components under narrow- and wide-angle conditions was maximal in the right parietal region, suggesting that processing of mental rotation is a right parietal dominant function.