1. Department of Integrative Medical Biology, Umeå University, SE-901 87 Umeå, Sweden
2. Umeå center for Functional Brain Imaging, Umeå University, SE-901 87 Umeå, Sweden
3. Centre for Demographic and Ageing Research at Umeå University (CEDAR), Umeå University, SE-901 87 Umeå, Sweden
4. Department of Radiation Sciences, Umeå University, SE-901 87 Umeå, Sweden