1. From the Cerebral Blood Flow Laboratory and Brain Injury Research Center (T.C.G., P.V., B.R., C.H., N.A.M.), Division of Neurosurgery, David Geffen School of Medicine, University of California at Los Angeles, and the Department of Neurosurgery (J.F.S.), Rambam Medical Center, Technion, B. Rappaport Faculty of Medicine, Haifa, Israel.