Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America.|Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America.|Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.|Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America.|Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America.