1. Department of Neurology, Kuopio University Hospital, Kuopio, Finland
2. Department of Physics, University of Eastern Finland, Kuopio, Finland
3. VTT Technical Research Centre of Finland, Tampere, Finland
4. Institute of Clinical Medicine, Neurology, University of Eastern Finland, Kuopio, Finland
5. Aging Research Center, Karolinska Institutet, Stockholm, Sweden
6. McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University Montreal, PQ, Canada
7. Department of Radiology, Kuopio University Hospital, Kuopio, Finland