[1] Univ Oxford, Oxford Ctr Funct Magnet Resonance Imaging Brain F, Oxford OX3 9DU, England
[2] Univ Oxford, Nuffield Dept Clin Neurosci, Oxford OX3 9DU, England
[3] Univ Estadual Campinas, Dept Neurol, UNICAMP, Sao Paulo, Brazil
[4] Ramathibodi Hosp, Dept Med, Div Neurol, Bangkok, Thailand
[5] City Univ London, Appl Vis Res Ctr, London EC1V 0HB, England
[6] Natl Hosp Neurol & Neurosurg, London WC1N 3BG, England
[7] Moorfields Eye Hosp, London, England