1. Department of Neurology, University Hospital Cologne, 50937 Cologne, Germany
2. Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, 52425 Jülich, Germany
3. Max-Planck-Institute for Metabolism Research, 50937 Cologne, Germany
4. Department of Nuclear Medicine, University Hospital Cologne, 50937 Cologne, Germany
5. Nuclear Chemistry, Institute of Neuroscience and Medicine (INM-5), Research Center Jülich, 52425 Jülich, Germany
6. Institute for Radiochemistry and Experimental Molecular Imaging, University Hospital Cologne, 50937 Cologne, Germany