1. Department of Neurology, University of Rostock, D‐18157 Rostock, Germany,
2. Human Cortical Physiology Section, National Institute of Neurological Disorders and Stroke, Medical Neurology Branch, National Institutes of Health, Bethesda, MD, USA
3. Human Cortical Pyhysiology and Motor Control Laboratory, Department of Neurology, University of Wuerzburg, D‐97080 Wuerzburg, Germany