[1] Univ Florida, Coll Med, Dept Neurosci, Gainesville, FL 32610 USA
[2] Univ Florida, Coll Publ Hlth & Hlth Profess, Dept Phys Therapy, Gainesville, FL USA
[3] Univ Cambridge, Sch Biol Sci, Dept Physiol Dev & Neurosci, Cambridge, England
[4] Univ Miami, Miller Sch Med, Miami Project Cure Paralysis, Miami, FL 33136 USA