1. Computational Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA
2. Institute for Neural Computation, University of California San Diego, La Jolla, California 92093, USA
3. Department of Neurosciences, University of California San Diego, La Jolla, California 92093, USA
4. US Combat Capabilities Development Command Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005, USA
5. Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
6. Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA