1Centre for Medical Image Computing, University College London, London, United Kingdom, 2Institute of Neurology, University College London, London, United Kingdom, 3Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), University of Oxford, Oxford, United Kingdom, 4Microsoft Research, Cambridge, United Kingdom, 5Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark