1. From the Metabolic and Molecular Imaging Group (APG, CGP, SS, ADM, NC, SSD, and JDB) and Robert Steiner MRI Unit (GD), Medical Research Council Clinical Sciences Centre, the Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Brain Sciences (CB), the Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism (MAG, DRA, GSF, and SRB), and the Divis