title: Dissociations within human hippocampal subregions during encoding and retrieval of spatial information.
abstract: Although the hippocampus is critical for the formation and retrieval of spatial memories, it is unclear how subregions are differentially involved in these processes. Previous high-resolution functional magnetic resonance imaging (fMRI) studies have shown that CA2, CA3, and dentate gyrus (CA23DG) regions support the encoding of novel associations, whereas the subicular cortices support the retrieval of these learned associations. Whether these subregions are used in humans during encoding and retrieval of spatial information has yet to be explored. Using high-resolution fMRI (1.6 mm × 1.6-mm in-plane), we found that activity within the right CA23DG increased during encoding compared to retrieval. Conversely, right subicular activity increased during retrieval compared to encoding of spatial associations. These results are consistent with the previous studies illustrating dissociations within human hippocampal subregions and further suggest that these regions are similarly involved during the encoding and retrieval of spatial information.
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, Center for Cognitive Neurosciences, Semel Institute, University of California, Los Angeles, USA.
authors.forename: Nanthia
authors.initials: N
authors.lastname: Suthana
authors.forename: Arne
authors.initials: A
authors.lastname: Ekstrom
authors.forename: Saba
authors.initials: S
authors.lastname: Moshirvaziri
authors.forename: Barbara
authors.initials: B
authors.lastname: Knowlton
authors.forename: Susan
authors.initials: S
authors.lastname: Bookheimer
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010775:Photic Stimulation / Q000379:methods*; D021641:Recognition, Psychology / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D055815:Young Adult