Time-dependent contribution of the hippocampal complex when remembering the past: a PET study.
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 remote memory dichotomy.
Tsukiura
Takashi
T
Brain Architecture Analysis Group, Neuroscience Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Japan. t-tsukiura@aist.go.jp
Fujii
Toshikatu
T
Okuda
Jiro
J
Ohtake
Hiroya
H
Kawashima
Ryuta
R
Itoh
Masatoshi
M
Fukuda
Hiroshi
H
Yamadori
Atsushi
A
D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology; D001930:Brain Injuries / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000502:physiology; D002648:Child; D007839:Functional Laterality / Q000502:physiology; D006624:Hippocampus / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D008569:Memory Disorders / Q000473:pathology / Q000503:physiopathology; D009434:Neural Pathways / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D009483:Neuropsychological Tests; D020534:Parahippocampal Gyrus / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D013998:Time Perception / Q000502:physiology*; D014055:Tomography, Emission-Computed