1. University of Duisburg-Essen Medical School, Department of Neurology, Essen, Germany
2. LWL-Klinik Muenster, Department of Addiction Disorders, Muenster, Germany
3. Istanbul Medipol University, Regenerative and Restorative Medical Research Center, Istanbul, Turkey
4. University of Goettingen Medical School, Department of Neurology, Goettingen, Germany