1. Departments of Neurosurgery, Columbia University, College of Physicians and Surgeons, New York, New York
2. Physiology, Columbia University, College of Physicians and Surgeons, New York, New York
3. Surgery, Columbia University, College of Physicians and Surgeons, New York, New York
4. Surgery, and Medicine, Columbia University, College of Physicians and Surgeons, New York, New York