title: Differential temporo-parietal cortical networks that support relational and item-based recency judgments.
abstract: There is a growing interest in the parietal cortical role for episodic memory retrieval. Previous functional magnetic resonance imaging (fMRI) studies of recency judgments, judgments of the relative temporal order of two studied items, have highlighted the involvement of the lateral prefrontal and medial temporal regions. However, the parietal cortical contribution to recency judgments has rarely been highlighted. To examine the parietal involvement, in this study, we conducted a re-analysis to increase the statistical power using three data sets (N=73) from our previous fMRI studies of recency judgments. Recency judgments can be achieved by at least two mechanisms, relational and item-based ones. It has been revealed that the left hippocampus/parahippocampal region is related to relational recency judgments, and that the right anterior temporal region is related to item-based recency judgments. We examined whether the parietal cortex is involved in these two types of recency judgments. Significant brain activity related to relational recency judgments was observed in the left ventral parietal region and, as reported previously, the left parahippocampal region. On the other hand, significant brain activity related to item-based recency judgments was observed in the left dorsal parietal region and, as reported previously, the right anterior temporal region. Furthermore, correlation analyses of resting-state BOLD signals detected significant correlations between the ventral parietal region and the parahippocampal region, as well as between the dorsal parietal region and anterior temporal region. These results suggest that the two temporo-parietal networks differentially contribute to relational and item-based recency judgments.
authors.affiliation: Department of Physiology, The University of Tokyo School of Medicine, Bunkyo-ku, Tokyo 113, Japan.
authors.forename: Hiroko M
authors.initials: HM
authors.lastname: Kimura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hirose
authors.forename: Akira
authors.initials: A
authors.lastname: Kunimatsu
authors.forename: Junichi
authors.initials: J
authors.lastname: Chikazoe
authors.forename: Koji
authors.initials: K
authors.lastname: Jimura
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Watanabe
authors.forename: Osamu
authors.initials: O
authors.lastname: Abe
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyashita
authors.forename: Seiki
authors.initials: S
authors.lastname: Konishi
mesh_terms: D000328:Adult; D001931:Brain Mapping; D003657:Decision Making / Q000502:physiology*; D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D013702:Temporal Lobe / Q000502:physiology*; D055815:Young Adult