Key points are not available for this paper at this time.
Neurology and *Psyehiatry Services, Massachusetts General Hospital, and the Neuroscience Program, Harvard Medical School, Boston, Massachusetts, U.S.A. Address correspondence and reprint requests to Dr. R. Maciewicz at Pain Physiology Laboratory, Burnham 7, Massachusetts General Hospital, Fruit Street, Boston, MA 02114, U.S.A.
Maciewicz et al. (1985) studied this question.