1. Departments of Neurosurgery, Charité-Universitaetsmedizin, Berlin, Germany
2. Departments of Neurology, Charité-Universitaetsmedizin, Berlin, Germany
3. Nexstim Ltd, Helsinki, Finland
4. Neuroscience Unit, Institute of Biomedicine/Physiology University of Helsinki, Helsinki, Finland
5. Department of Physiology University of Eastern Finland, Kuopio, Finland