School of Medicine, Vanderbilt University, Nashville, Tennessee, USA. Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA. Department of Psychiatry, Harvard Medical School, McLean Hospital, Boston, Massachusetts, USA. Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA. Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA. Electronic address: chris.bonfield@vanderbilt.edu.