Exercise boosts hippocampal volume by preventing early age-related gray matter loss Johannes Fuss 1 * # , Sarah V. Biedermann 2,3 *, Claudia Falfán-Melgoza 2 , Matthias K. Auer 1,4 , Lei Zheng 5 , Jörg Steinle 1 , Felix Hörner 2 , Alexander Sartorius 2 , Gabriele Ende 3 , Wolfgang Weber-Fahr 2,3 *, and Peter Gass 1 * 1 RG Animal models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health Mannheim (ZI), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany 2 RG Translational Imaging, Departments of Neuroimaging and Psychiatry and Psychotherapy, Central Institute of Mental Health Mannheim (ZI), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany 3 Department of Neuroimaging, Central Institute of Mental Health Mannheim (ZI), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany 4 Department of Endocrinology, Max Planck Institute of Psychiatry, Munich, Germany 5 Experimental Radiation Oncology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany * both authors contributed equally (shared first and last authorship) Short Title: Exercise modulates hippocampal aging Number of pages: 12, Tables: 0, Figures: 3, Supplementary material: 3 # Corresponding author Central Institute of Mental Health J 5 68159 Mannheim Germany Mail: johannes.fuss@zi-mannheim.de Tel.: ++49 621 1703 2932 Fax: ++49 621 1703 2005 This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as an ‘Accepted Article’, doi: 10.1002/hipo.22227