An fMRI study on autobiographical memory retrieval

Autobiographical memory is a memory for events and issues related to oneself and may be differently structured from other memories. To clarify the difference, we investigated an fMRI study of activated regions in the human brain in autobiographical memory retrieval. Each subject experienced two types of tasks, TASK1 and TASK2. In TASK1, the subject was requested to read a brief sentence in which an episode in his/her own past was described, then to silently make an image of the situation in his/her mind. In TASK2, in contrast, the subject was requested to read a sentence describing the other person's episode, and to make its image. The block-designed fMRI measurement was performed in three conditions: TASK1 vs. REST where the subject laid at rest, TASK2 vs. REST, and TASK1 vs. TASK2. Both in TASK1 vs. REST and in TASK2 vs. REST, increasing relative regional cerebral blood flow (rCBF) was observed in the striate cortex, the supplementary motor area, the frontal eye field, the frontal association area, and the cerebellum. The area of activated regions in autobiographical memory retrieval was larger than that in nonautobiographical memory retrieval. In the comparison of TASK1 vs. TASK2, relative rCBF increased in the frontal association area and inferior parietal lobule. The result in the TASK1 vs. TASK2 condition shows the possibility that the neural activity in the prefrontal area is specifically related to an ecphory of autobiographical information. (C) 2004 Published by Elsevier B.V.