1. Departments of Electrical Engineering,
2. Bioengineering, and Neurobiology, Bio-X and Neurosciences Programs, Stanford Institute for Neuro-Innovation and Translational Neuroscience, Stanford University, Stanford, California 94305;
3. Gatsby Computational Neuroscience Unit, University College London, London WC1N 3AR, United Kingdom;
4. Department of Neuroscience, Grossman Center for the Statistics of Mind, David Mahoney Center for Brain and Behavior Research, Kavli Institute for Brain Science, Columbia University Medical Center, New York, NY 10032;