Functional suppression of long-term sustained response in the human hippocampal formation due to memory distraction

Functional magnetic resonance imaging is used to investigate physiological dynamics in the human hippocampal formation due to memory distraction. A finger-movement task executed following a verbal memory task resulted in decreased verbal memory scores and shortening of active response in the hippocampal formation and the cerebellar dentate nucleus. Verbal rehearsal was excluded as an explanation because this sustained activation was approximately three-fold longer than the duration of the post-task activation observed in classical language processing regions such as Wernicke's and Broca's areas. These interference phenomena provide a physiological basis of memory distraction in the hippocampal formation.