1. Department of Human Communication Science, University College London, 2 Wakefield Street, London WC1N 1PG, UK
2. Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
3. Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
4. Guy's, King's and Thomas' School of Medicine, London SE5 9PJ, UK
5. Department of Language and Communication Science, City University, London EC1V 0HB, UK