Gunnar Blohm1, Paul Schrater2, Konrad Körding3. 1. Centre for Neuroscience Research, Queen's University, Kingston, ON K7L 3N6, Canada gunnar.blohm@queensu.ca. 2. Departments of Psychology and Computer Science, University of Minnesota, Minneapolis 55455, U.S.A. schrater@umn.edu. 3. Departments of Bioengineering and Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, U.S.A. konrad@koerding.com.