title: Resting state functional connectivity of the hippocampus along the anterior-posterior axis and its association with glutamatergic metabolism.
abstract: Animal and human studies suggest differing anatomical and functional connectivity patterns of the anterior and posterior hippocampus. The biochemical underpinnings of the hippocampal resting state connectivity along this anterior-posterior axis remain unclear. We investigated twenty-five healthy male subjects in a multimodal study. We aimed to examine the relationship between resting state functional connectivity (RSFC) of the left and right hippocampus separated along the anterior-posterior axis and the corresponding glutamatergic function assessed by proton magnetic resonance spectroscopy ((1)H-MRS) of the glutamate-glutamine (Glx) complex. We observed a clear functional differentiation of the hippocampal RSFC along this axis. Moreover, a highly significant correlation was observed between the concentration of Glx in the right anterior hippocampus and its corresponding functional connectivity, but not with the amplitude of local low frequency fluctuations. Lower Glx levels were associated with a higher functional connectivity to the medial prefrontal cortex, perigenual anterior cingulate cortex (pACC) and the left ventrolateral prefrontal cortex (VLPFC). In addition, the Glx concentration in the posterior hippocampus predicted the verbal memory performance, i.e., the degree of retroactive interference. The present findings demonstrate for the first time a modulation of the anterior hippocampal RSFC by Glx concentration.
authors.affiliation: Psychiatric Brain & Body Research Group Jena, Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany. Electronic address: wagner.gerd@uni-jena.de.
authors.forename: Gerd
authors.initials: G
authors.lastname: Wagner
authors.affiliation: Medical Physics Group, Department of Diagnostic and Interventional Radiology, Jena University Hospital, Jena, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Gussew
authors.affiliation: Psychiatric Brain & Body Research Group Jena, Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Köhler
authors.affiliation: Psychiatric Brain & Body Research Group Jena, Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany.
authors.forename: Feliberto
authors.initials: F
authors.lastname: de la Cruz
authors.affiliation: Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Smesny
authors.affiliation: Medical Physics Group, Department of Diagnostic and Interventional Radiology, Jena University Hospital, Jena, Germany.
authors.forename: Jürgen R
authors.initials: JR
authors.lastname: Reichenbach
authors.affiliation: Psychiatric Brain & Body Research Group Jena, Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany.
authors.forename: Karl-Jürgen
authors.initials: KJ
authors.lastname: Bär
mesh_terms: D000328:Adult; D001931:Brain Mapping; D018698:Glutamic Acid / Q000378:metabolism; D006179:Gyrus Cinguli / Q000502:physiology*; D006624:Hippocampus / Q000473:pathology / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009434:Neural Pathways / Q000502:physiology* / Q000503:physiopathology; D017397:Prefrontal Cortex / Q000502:physiology*; D012146:Rest / Q000502:physiology*
chemical_list: D018698:Glutamic Acid
keywords: Glutamate; Hippocampus; MRS; Resting state functional connectivity; fMRI