1. Department for Cognitive Neurology, University Clinic Tübingen, Schaffhausenstr.113, 72072 Tübingen, Germany
2. Department for Empirical Inference for Machine Learning and Perception, Max Planck Institute for Biological Cybernetics, Spemannstr. 38, 72076 Tübingen, Germany
3. Graphical-Interactive Systems, Wilhelm Schickard Institute for Computer Science, University of Tübingen, Germany, Sand 14, 72076 Tübingen, Germany