1. Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA.
2. Department of Neurosurgery, University of Pittsburgh, Pittsburgh, PA 15213, USA.
3. Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA.
4. Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15213, USA.
5. Department of Biology, University of Pittsburgh, Greensburg, PA 15601, USA.
6. Department of Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
7. Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA 15213, USA.
8. McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA.