1 Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States.
2 Departments of Neurology and Biochemistry, Neuroethics Studies Program-Pellegrino Center for Clinical Bioethics, Georgetown University Medical Center, Washington, DC, United States.
3 Department of Neurological Surgery, Perelman School of Medicine at the University of Pennsylvania Richards Medical Research Laboratories, Philadelphia, PA, United States.