Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, United States of America.|Department of Psychological & Brain Sciences, University of California, Santa Barbara, Santa Barbara, California, United States of America.|Department of Physics, University of California, Santa Barbara, Santa Barbara, California, United States of America.|Department of Psychological & Brain Sciences, University of California, Santa Barbara, Santa Barbara, California, United States of America.|Department of Psychological & Brain Sciences, University of California, Santa Barbara, Santa Barbara, California, United States of America.|Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.|Department of Physics, University of California, Santa Barbara, Santa Barbara, California, United States of America.