1 Division of Neurobiology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.
2 International Center for Primate Brain Research, Center for Excellence in Brain Science and Intelligence, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, China.
3 Werner Reichardt Center for Integrative Neuroscience, Karl Eberhard University of Tübingen, Tübingen, Germany.
4 Max Planck Institute for Biological Cybernetics, Tübingen, Germany.