J Patrick Mayo1, Bram-Ernst Verhoef2. 1. Department of Neurobiology, Harvard Medical School, Boston, Massachussetts 02115, and patrick_mayo@hms.harvard.edu bram-ernst_verhoef@hms.harvard.edu. 2. Department of Neurobiology, Harvard Medical School, Boston, Massachussetts 02115, and Laboratory for Neuro-en Psychophysiology, KU Leuven, Campus Gasthuisberg, BE 3000 Leuven, Belgium patrick_mayo@hms.harvard.edu bram-ernst_verhoef@hms.harvard.edu.