title: The hippocampus and exercise: histological correlates of MR-detected volume changes.
abstract: Growing evidence indicates that physical exercise increases hippocampal volume. This has consistently been shown in mice and men using magnetic resonance imaging. On the other hand, histological studies have reported profound alterations on a cellular level including increased adult hippocampal neurogenesis after exercise. A combined investigation of both phenomena has not been documented so far although a causal role of adult neurogenesis for increased hippocampal volume has been suggested before. We investigated 20 voluntary wheel running and 20 sedentary mice after a period of 2 month voluntary wheel running. Half of each group received focalized hippocampal irradiation to inhibit neurogenesis prior to wheel running. Structural MRI and histological investigations concerning newborn neurons (DCX), glial cells (GFAP), microglia, proliferating and pyknotic cells, neuronal activation, as well as blood vessel density and arborisation were performed. In a regression model, neurogenesis was the marker best explaining hippocampal gray matter volume. Individual analyses showed a positive correlation of gray matter volume with DCX-positive newborn neurons in the subgroups, too. GFAP-positive cells significantly interacted with gray matter volume with a positive correlation in sham-irradiated mice and no correlation in irradiated mice. Although neurogenesis appears to be an important marker of higher hippocampal gray matter volume, a monocausal relationship was not indicated, requesting further investigations.
authors.affiliation: Departments of Neuroimaging and Psychiatry and Psychotherapy, Medical Faculty Mannheim, Central Institute of Mental Health Mannheim (ZI), RG Translational Imaging, University of Heidelberg, Mannheim, Germany.|Department of Neuroimaging, Medical Faculty Mannheim, Central Institute of Mental Health Mannheim (ZI), University of Heidelberg, Mannheim, Germany.
authors.forename: Sarah V
authors.initials: SV
authors.lastname: Biedermann
authors.affiliation: Department of Psychiatry and Psychotherapy, Medical Faculty Mannheim, Central Institute of Mental Health Mannheim (ZI), RG Animal Models in Psychiatry, University of Heidelberg, J 5, 68159, Mannheim, Germany. jo.fuss@uke.de.
authors.forename: Johannes
authors.initials: J
authors.lastname: Fuss
authors.affiliation: Department of Psychiatry and Psychotherapy, Medical Faculty Mannheim, Central Institute of Mental Health Mannheim (ZI), RG Animal Models in Psychiatry, University of Heidelberg, J 5, 68159, Mannheim, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Steinle
authors.affiliation: Department of Psychiatry and Psychotherapy, Medical Faculty Mannheim, Central Institute of Mental Health Mannheim (ZI), RG Animal Models in Psychiatry, University of Heidelberg, J 5, 68159, Mannheim, Germany.|Department of Endocrinology, Max Planck Institute of Psychiatry, Munich, Germany.
authors.forename: Matthias K
authors.initials: MK
authors.lastname: Auer
authors.affiliation: Department of Psychiatry and Psychotherapy, Medical Faculty Mannheim, Central Institute of Mental Health Mannheim (ZI), RG Animal Models in Psychiatry, University of Heidelberg, J 5, 68159, Mannheim, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Dormann
authors.affiliation: Department of Neuroimaging, Medical Faculty Mannheim, Central Institute of Mental Health Mannheim (ZI), University of Heidelberg, Mannheim, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Falfán-Melgoza
authors.affiliation: Department of Neuroimaging, Medical Faculty Mannheim, Central Institute of Mental Health Mannheim (ZI), University of Heidelberg, Mannheim, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Ende
authors.affiliation: Department of Psychiatry and Psychotherapy, Medical Faculty Mannheim, Central Institute of Mental Health Mannheim (ZI), RG Animal Models in Psychiatry, University of Heidelberg, J 5, 68159, Mannheim, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Gass
authors.affiliation: Departments of Neuroimaging and Psychiatry and Psychotherapy, Medical Faculty Mannheim, Central Institute of Mental Health Mannheim (ZI), RG Translational Imaging, University of Heidelberg, Mannheim, Germany.|Department of Neuroimaging, Medical Faculty Mannheim, Central Institute of Mental Health Mannheim (ZI), University of Heidelberg, Mannheim, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Weber-Fahr
mesh_terms: D000818:Animals; D017209:Apoptosis; D000089662:Doublecortin Protein; D006624:Hippocampus / Q000098:blood supply / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects; D008279:Magnetic Resonance Imaging; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000166:cytology / Q000502:physiology; D055495:Neurogenesis / Q000528:radiation effects; D009457:Neuroglia / Q000166:cytology / Q000502:physiology; D009473:Neuronal Plasticity; D009474:Neurons / Q000166:cytology / Q000502:physiology; D010805:Physical Conditioning, Animal
keywords: Exercise; Hippocampus; Histology; Magnetic resonance imaging; Neurogenesis; Voxel-based morphometry