Human hippocampal long-term sustained response during word memory processing

TEMPORAL behavior of activation associated with the neural substrate of human memory function was investigated during and after an auditorily instructed word memory task using multislice functional magnetic resonance imaging. The hippocampal formation, which is involved in human memory function, displayed a longterm sustained response that persisted significantly (similar to 90 s) beyond the duration of the memory task. This sustained period was similar to two-fold longer than the duration of the post-task activation observed in auditory areas and Broca's area, which are involved in the phonological loop of the verbal working memory. These observations suggest that the hippocampal memory processing involves sustained activation in the transitional function for the long-term memory over the working memory period. (C) 1998 Rapid Science Ltd.