1. From the Brain Research Imaging Center (J.M.W., F.N.D., M.V.H., X.W., F.M.C., K.S., P.A.A., T.C.C.), and Stroke Medicine (J.M.W., F.N.D.,M.S.D.), Division of Clinical Neurosciences, University of Edinburgh, Edinburgh, United Kingdom; Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh, United Kingdom (J.M.W., M.V.H., X.W., F.M.C., K.S., P.A.A., T.C.C.); and Center for Cognitive Aging and Cognitive Epidemiology, University of Edinburgh, Edinburgh, United...