title: Decreased fronto-temporal interaction during fixation after memory retrieval.
abstract: Previous studies have revealed top-down control during memory retrieval from the prefrontal cortex to the temporal cortex. In the present functional MRI study, we investigated whether the fronto-temporal functional interaction occurs even during fixation periods after memory retrieval trials. During recency judgments, subjects judged the temporal order of two items in a study list. The task used in the present study consisted of memory trials of recency judgments and non-memory trials of counting dots, and post-trial fixation periods. By comparing the brain activity during the fixation periods after the memory trials with that during the fixation periods after the non-memory trials, we detected heightened brain activity in the lateral prefrontal cortex, the lateral temporal cortex and the hippocampus. Functional interactions during the fixation periods after the memory vs. non-memory trials as examined using a psychophysiological interaction revealed a decreased interaction from the lateral prefrontal cortex to the lateral temporal cortex, but not to the hippocampus. The functional interaction between the same frontal and temporal regions was also present during the memory trials. A trial-based functional connectivity analysis further revealed that the fronto-temporal interaction was positive and decreased during the fixation periods after the memory trials, relative to the fixation periods after the non-memory trials. These results suggest that the fronto-temporal interaction existed during the post-trial fixation periods, which had been present during the memory trials and temporally extended into the fixation periods.
authors.affiliation: Department of Radiology, The University of Tokyo School of Medicine, Tokyo, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Katsura
authors.affiliation: Department of Physiology, The University of Tokyo School of Medicine, Tokyo, Japan; Department of Physiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hirose
authors.affiliation: Department of Radiology, The University of Tokyo School of Medicine, Tokyo, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sasaki
authors.affiliation: Department of Radiology, The University of Tokyo School of Medicine, Tokyo, Japan.
authors.forename: Harushi
authors.initials: H
authors.lastname: Mori
authors.affiliation: Department of Radiology, The University of Tokyo School of Medicine, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kunimatsu
authors.affiliation: Department of Radiology, The University of Tokyo School of Medicine, Tokyo, Japan.
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
authors.affiliation: Department of Physiology, The University of Tokyo School of Medicine, Tokyo, Japan; Department of Physiology, Juntendo University School of Medicine, Tokyo, Japan; Precision and Intelligence Laboratory, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Jimura
authors.affiliation: Department of Physiology, The University of Tokyo School of Medicine, Tokyo, Japan; Department of Physiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Seiki
authors.initials: S
authors.lastname: Konishi
mesh_terms: D000328:Adult; D001519:Behavior; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D059906:Neuroimaging; D017397:Prefrontal Cortex / Q000502:physiology*; D013702:Temporal Lobe / Q000502:physiology*; D055815:Young Adult