title: The medial temporal lobe supports conceptual implicit memory.
abstract: The medial temporal lobe (MTL) is generally thought to be critical for explicit, but not implicit, memory. Here, we demonstrate that the perirhinal cortex (PRc), within the MTL, plays a role in conceptually-driven implicit memory. Amnesic patients with MTL lesions that converged on the left PRc exhibited deficits on two conceptual implicit tasks (i.e., exemplar generation and semantic decision). A separate functional magnetic resonance imaging (fMRI) study in healthy subjects indicated that PRc activation during encoding of words was predictive of subsequent exemplar generation. Moreover, across subjects, the magnitude of the fMRI and behavioral conceptual priming effects were directly related. Additionally, the PRc region implicated in the fMRI study was the same region of maximal lesion overlap in the patients with impaired conceptual priming. These patient and imaging results converge to suggest that the PRc plays a critical role in conceptual implicit memory, and possibly conceptual processing in general.
authors.affiliation: Department of Psychology, University of California, Davis, Davis, CA 95616, USA. wwa@ucdavis.edu
authors.forename: Wei-Chun
authors.initials: WC
authors.lastname: Wang
authors.forename: Michele M
authors.initials: MM
authors.lastname: Lazzara
authors.forename: Charan
authors.initials: C
authors.lastname: Ranganath
authors.forename: Robert T
authors.initials: RT
authors.lastname: Knight
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Yonelinas
mesh_terms: D000328:Adult; D000647:Amnesia / Q000209:etiology / Q000503:physiopathology*; D001364:Awareness / Q000502:physiology; D001925:Brain Damage, Chronic / Q000150:complications / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D016022:Case-Control Studies; D003210:Concept Formation / Q000502:physiology*; D003463:Cues; D004193:Discrimination Learning / Q000502:physiology; D006801:Humans; D002534:Hypoxia, Brain / Q000150:complications / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D021641:Recognition, Psychology / Q000502:physiology*; D012016:Reference Values; D013702:Temporal Lobe / Q000473:pathology / Q000502:physiology* / Q000503:physiopathology; D014706:Verbal Learning / Q000502:physiology; D055815:Young Adult