[1] Johns Hopkins Univ, Sch Med, Dept Neurol, Baltimore, MD 21205 USA
[2] Kennedy Krieger Inc, Hugo W Moser Res Inst, Int Ctr Spinal Cord Injury, Baltimore, MD USA
[3] Kennedy Krieger Inst, FM Kirby Res Ctr Funct Brain Imaging, Baltimore, MD USA
[4] Johns Hopkins Univ, Sch Med, Russell H Morgan Dept Radiol & Radiol Sci, Baltimore, MD 21205 USA
[5] Johns Hopkins Univ, Sch Med, Baltimore, MD 21205 USA
[6] Vanderbilt Univ, Dept Radiol & Radiol Sci, Inst Imaging Sci, Nashville, TN 37235 USA