Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.|Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.|Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.|Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.|Department of Biological Sciences, Columbia University, New York, NY, United States of America.|Department of Psychiatry, University of Cambridge, Cambridge United Kingdom.|Department of Psychiatry, University of Cambridge, Cambridge United Kingdom.|Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.