1. Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.
2. Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
3. Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
4. Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA.