Unité de Neurosciences, Information et Complexité, CNRS UPR 3293, Gif-sur-Yvette, France.|Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.|Institute for Adaptive and Neural Computation, University of Edinburgh, Edinburgh, United Kingdom.|Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.