1. Department of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, 37075 Göttingen,
2. European Research Training Network (RTN) ‘Nervous System Repair’
3. DFG-Research Center for Molecular Physiology of the Brain (CMPB), Göttingen, Germany
4. Burnham Institute for Medical Research, La Jolla, California 92037, USA