title: The role of the basal forebrain in episodic memory retrieval: a positron emission tomography study.
abstract: Human lesion data indicate that the basal forebrain or orbitofrontal cortex, or both, as well as medial temporal and diencephalic structures, is important for normal memory and that its disruption causes the pure amnesic syndrome, in which episodic memory is grossly impaired while other kinds of memory remain preserved. Among these critical areas, functional imaging studies have so far failed to detect activation of the basal forebrain, although activation in the nearby orbitofrontal cortex has been reported during episodic memory retrieval. We employed positron emission tomography to elucidate the neural basis of episodic memory recall utilizing two types of time cues and successfully detected activity in the basal forebrain for the first time. Specifically, recall of previously memorized words from temporal cues was associated with activity in the basal forebrain, right middle frontal gyrus, right superior temporal gyrus, and posterior cingulate gyrus, whereas their recall from person cues was associated with activity in the left insula, right middle frontal gyrus, and posterior cingulate gyrus. Furthermore, percentage increases of regional blood flow in the basal forebrain were correlated with behavioral data of successful recall. Our results provide clear evidence that the human basal forebrain has a specific role in episodic memory recall, especially that from time-contextual information.
authors.affiliation: Division of Neuropsychology, Graduate School of Medicine, Tohoku University, Sendai 980-8575, Japan.
authors.forename: Toshikatsu
authors.initials: T
authors.lastname: Fujii
authors.forename: Jiro
authors.initials: J
authors.lastname: Okuda
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsukiura
authors.forename: Hiroya
authors.initials: H
authors.lastname: Ohtake
authors.forename: Rina
authors.initials: R
authors.lastname: Miura
authors.forename: Reiko
authors.initials: R
authors.lastname: Fukatsu
authors.forename: Kyoko
authors.initials: K
authors.lastname: Suzuki
authors.forename: Ryuta
authors.initials: R
authors.lastname: Kawashima
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Itoh
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukuda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamadori
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000502:physiology; D006179:Gyrus Cinguli / Q000000981:diagnostic imaging / Q000502:physiology; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D016548:Prosencephalon / Q000000981:diagnostic imaging / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000502:physiology; D014055:Tomography, Emission-Computed; D014706:Verbal Learning / Q000502:physiology*