1. From the Department of Anesthesia and Pain Management and the Toronto General Hospital Research Institute (J.A.F., L.V.)
2. Department of Anesthesiology (J.A.F., L.V.)
3. Institute of Medical Sciences (J.A.F., D.J.M.)
4. Department of Physiology (J.A.F.), University of Toronto, Canada.
5. Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory (D.J.M.), University Health Network, Toronto, Canada