By Adina Michael-Titus, Senior Lecturer in Neuroscience and Pharmacology, St Bartholomew's and the Royal London School of Medicine and Dentistry, London, UK Patricia Revest, MBCHB, BA, PHD, Centre for Medical Eduation, Barts and the London School of Medicine and Dentistry, London, UK Peter Shortland, Lecturer in Anatomy, Neuroscience Section, Queen Mary and Westfield College, London, UK