T1-weighted MRI data were collected with General Electric 1.5T scanners at Johns Hopkins University (n=30); Mt. Sinai School of Medicine (n=25); University of California at San Diego (n=47); University of Texas Medical Branch (n=29) and the University of Washington (n=8). 3D T1-weighted images were acquired sagittally with spoiled gradient recall (SPGR), TR = 20ms, TE = 6ms, flip angle = 30°, field-of-view = 240mm,124 slices of 1.3mm, in-plane resolution 0.94x0.94mm as previously described.4 (link)3D T1 images were pre-processed as described previously using SPM12 (University College London, UK).6 (link) Briefly, images were bias corrected, segmented into grey matter, white matter and cerebrospinal fluid (CSF), volumes calculated with the sum representing the total intracranial volume (TICV). Segmented images were then registered to a custom template, normalised to Montreal Neurological Institute (MNI) space using the DARTEL algorithm,23 (link) modulated to retain the volumetric characteristics of the original data and smoothed with a 6mm full width half maximum kernel. To take advantage of the complementary data provided by grey and white matter, spatially normalised grey and white matter volumetric maps were spatially concatenated prior to multivariate analysis.