1 Research Service, VAMHCS, 10 North Greene Street, Baltimore 21201, MD, USA
2 Department of Neurology, University of Maryland, School of Medicine, Baltimore 21201, MD, USA
3 Program in Neuroscience and Cognitive Sciences, University of Maryland, College Park 20742, MD, USA
4 Department of Anesthesiology, Center for Shock, Trauma and Anesthesiology Research, School of Medicine, Baltimore 21201, MD, USA
5 Neurology Service, VAMHCS, Baltimore 21201, MD, USA
6 Present address: Department of Neurotrauma, Henry M. Jackson Foundation, Naval Medical Research Center, Silver Spring 20910, MD, USA