title: Differential effect of age on hippocampal subfields assessed using a new high-resolution 3T MR sequence.
abstract: Recent advances in neuroimaging have highlighted the interest to differentiate hippocampal subfields for cognitive neurosciences and more notably in assessing the effects of normal and pathological aging. The main goal of the present study is to investigate the effects of normal aging onto the volume of the different hippocampal subfields. For this purpose, we developed a new magnetic resonance sequence together with reliable tracing guidelines to assess the volume of different subfields of the hippocampus using a 3 Tesla scanner, and estimated the validity of a simpler and less time-consuming method based on the widely-used automatic Voxel-Based Morphometry (VBM) technique. Three hippocampal regions of interest were delineated on the right and left hippocampi of 50 healthy subjects between 18 and 68 years old corresponding to the CA1, subiculum and other (including CA2-3-4 and Dentate Gyrus) subfields. A strong effect of age was found on the volume of the subiculum only, with a decrease paralleling that of the global gray matter volume, while CA1 and other subfields seemed relatively spared. Although less precise than the ROI-tracing technique, the VBM-based method appeared as a reliable alternative especially to distinguish CA1 and subiculum subfields. Our findings of a specific effect of age on the subiculum are consistent with the developmental hypothesis ("last-in first-out" theory). This contrasts with the predominant vulnerability of the CA1 subfield to Alzheimer's disease reported in several previous studies, suggesting that the assessment of hippocampal subfields may improve the discrimination between normal and pathological aging.
authors.affiliation: Inserm-EPHE, Université de Caen/Basse-Normandie, Unité U923, GIP Cyceron, CHU Côte de Nacre, Caen, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: La Joie
authors.forename: Marine
authors.initials: M
authors.lastname: Fouquet
authors.forename: Florence
authors.initials: F
authors.lastname: Mézenge
authors.forename: Brigitte
authors.initials: B
authors.lastname: Landeau
authors.forename: Nicolas
authors.initials: N
authors.lastname: Villain
authors.forename: Katell
authors.initials: K
authors.lastname: Mevel
authors.forename: Alice
authors.initials: A
authors.lastname: Pélerin
authors.forename: Francis
authors.initials: F
authors.lastname: Eustache
authors.forename: Béatrice
authors.initials: B
authors.lastname: Desgranges
authors.forename: Gaël
authors.initials: G
authors.lastname: Chételat
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D056547:CA1 Region, Hippocampal / Q000033:anatomy & histology; D056654:CA3 Region, Hippocampal / Q000033:anatomy & histology; D004493:Education; D005260:Female; D006624:Hippocampus / Q000033:anatomy & histology* / Q000254:growth & development; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012016:Reference Values; D015203:Reproducibility of Results; D012727:Sex Characteristics; D012984:Software; D055815:Young Adult