Time-dependent contribution of the hippocampal complex when ... : NeuroReport (original) (raw)

Brain Imaging

Time-dependent contribution of the hippocampal complex when remembering the past: a PET study

Tsukiura, TakashiCA; Fujii, Toshikatu1; Okuda, Jiro1 2; Ohtake, Hiroya1; Kawashima, Ryuta3 4; Itoh, Masatoshi5; Fukuda, Hiroshi4; Yamadori, Atsushi1

Brain Architecture Analysis Group, Neuroscience Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 2, 1-1-1 Umezono, Tsukuba 305-8568

1Division of Neuropsychology, Department of Disability Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575

2The Japan Society for the Promotion of Science, 5-3-1 Kouji-machi, Chiyoda-ku, Tokyo 102-0083

3New Industry Creation Hatchery Center, Tohoku University, Aoba Aramaki Aoba-ku Sendai 980-8579

4Department of Nuclear Medicine and Radiology, IDAC, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575

5Cyclotron and Radioisotope Center, Tohoku University, Aoba-ku, Sendai 980-8575/8, Japan

CACorresponding Author: [email protected]

Received 14 June 2002; accepted 8 October 2002

Abstract

Previous studies of brain-damaged patients and functional neuro-imaging have consistently shown the importance of the hippocampal complex, i.e. the hippocampus and parahippocampal gyrus, in episodic memory retrieval. We wished to determine whether patterns of brain activation during memory retrieval as measured by PET are same or different when the oldness of a to-be-retrieved episode is manipulated. Using cue words, subjects remembered related episodes from three periods of their life, childhood, adolescence and recent period. The results showed an increase of parahippocampal activities during recall of episodes from childhood and recent period, but not from adolescence. These data suggest a possibility of time-dependent hippocampal contribution in episodic recall, which cannot be understood in simple terms of recent vs remote memory dichotomy.