1. Institute of Psychiatry, King's College London, Denmark Hill, London, SE5 8AF, UK, http://www.kcl.ac.uk/iop/index.aspx
2. Department of Chemistry, Imperial College London, London, SW7 2AZ, UK, http://www.ch.ic.ac.uk/long/
3. Division of Imaging Sciences and Biomedical Engineering, King's College London, The Rayne Institute, St Thomas's Hospital, London, SE1 7EH, UK