1. College of Medicine, University of Florida, Gainesville, FL 32601, USA
2. School of Medicine, University of California, Irvine, CA 92617, USA
3. School of Medicine, Campbell University, Lillington, NC 27546, USA
4. Alix School of Medicine, Mayo Clinic, Scottsdale, AZ 85054, USA
5. Department of Neurosurgery, University of Florida, Gainesville, FL 32608, USA