1. Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
2. Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
3. Bioengineering Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
4. jburge@psych.upenn.edu
5. Department of Psychology, University of Texas at Austin, Austin, TX, USA
6. Center for Perceptual Systems, University of Texas at Austin, Austin, TX, USA
7. Institute for Neuroscience, University of Texas at Austin, Austin, TX, USA
8. cormack@utexas.edu