1. Department of Computer Science, The University of Tennessee, Knoxville, TN 37996, USA
2. Department of Anatomy and Neurobiology, The University of Tennessee, Memphis, TN 38163, USA
3. Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
4. Harvard Center for Neurodegeneration & Repair and Brigham and Women's Hospital, Harvard Medical School, Harvard University, Boston, MA 02115, USA