1. From the Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne (M.H., H.T., K.G., G.N.B., A.D.), University of Cologne; Institute of Neuroscience and Medicine (INM-2) (M.H., K.G., A.D.), Molecular Organization of the Brain, Forschungszentrum Jülich, Germany; Neurology Unit (D.A.), Department of Clinical and Experimental Sciences, University of Brescia, Italy; Laboratory of Neuroimaging of Aging (LANVIE) (D.A.), University of Geneva; Geneva Memory Center (D.A., C.C., G.B...