[1] Univ Penn, Dept Neurol, 3400 Spruce St, Philadelphia, PA 19104 USA
[2] Walter Reed Natl Mil Med Ctr, Natl Intrepid Ctr Excellence, Palmer Rd S, Bethesda, MD 20814 USA
[3] Uniformed Serv Univ Hlth Sci, Dept Neurosci, 4301 Jones Bridge Rd, Bethesda, MD 20814 USA