To cite: Proudfoot M, Woolrich MW, Nobre AC, et al. Pract Neurol 2014;14:336–343. INTRODUCTION The understanding of brain function is moving rapidly towards a systems-level, network-based approach. It is now as naive to talk simplistically about what a particular area of the brain ‘does’, as it was for Franz Joseph Gall (1758–1828) to link its performance to the thickness of the overlying skull...