1. Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
2. Cyclotron Research Centre and Neurology Department, University and University Hospital of Liège, Liège, Belgium
3. Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
4. Centre for Advanced Imaging, University of Queensland, Brisbane, Australia
5. Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
6. Department of Biomedicine—Pharmacology, Aarhus University, Aarhus, Denmark
7. Department of Nuclear Medicine, University Hospital of Liège, Liège, Belgium
8. Department of Neurology, McGill University, Montréal, Québec, Canada
9. Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA