aNuffield Department of Clinical Neurosciences, Division of Clinical Neurology, John Radcliffe Hospital, University of Oxford, Oxford bDepartment of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK Correspondence to Chrystalina A. Antoniades, PhD, Nuffield Department of Clinical Neurosciences, Division of Clinical Neurology, Level 6 West Wing, John Radcliffe Hospital, University of Oxford, Oxford, UK Tel: +0186 523 4728; fax: +44 186 523 4728; e-mail: [email protected] Received April 2, 2012 Accepted April 2, 2012