1. From the Department of Pharmacology and Clinical Neuroscience, Umeå, Sweden (L.Z., J.M.)
2. Department of Surgical and Perioperative Sciences, Umeå, Sweden (L.Z.)
3. Department of Radiation Science, Umeå, Sweden (A.W., K.A., R.B., A.E.)
4. Centre for Biomedical Engineering and Physics, Umeå, Sweden (A.W., K.A., A.E.)
5. Umeå Center for Functional Brain Imaging, Sweden (A.W., A.E.).