1. Neuroscience Statistics Research Laboratory, Department of Anesthesia and Critical Care, Massachusetts General Hospital, Boston, MA 02114, U.S.A., and Division of Health Sciences and Technology, Harvard Medical School = Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A.
2. Neuroscience Statistics Research Laboratory, Department of Anesthesia and Critical Care, Massachusetts General Hospital, Boston, MA 02114, U.S.A.,
3. Department of Statistics, Carnegie Mellon University, Center for the Neural Basis of Cognition, Pittsburg, PA 15213, U.S.A.
4. Neuroscience Statistics Research Laboratory, Department of Anesthesia and Critical Care, Massachusetts General Hospital, Boston, MA 02114, U.S.A.