[1] WASHINGTON UNIV, DEPT NEUROL, ST LOUIS, MO 63110 USA
[2] WASHINGTON UNIV, DEPT ANAT & NEUROBIOL, ST LOUIS, MO 63110 USA
[3] WASHINGTON UNIV, DEPT PREVENT MED, ST LOUIS, MO 63110 USA
[4] UNIV CHICAGO, DEPT PHARMACOL & PHYSIOL SCI & NEUROL, CHICAGO, IL 60637 USA
[5] CORNELL UNIV, MED CTR, COLL MED, DEPT NEUROL, NEUROBIOL LAB, NEW YORK, NY 10021 USA