[1] UNIV CALIF SAN DIEGO, HOWARD HUGHES MED INST, DEPT MED, LA JOLLA, CA 92093 USA
[2] UNIV CALIF SAN DIEGO, SCH MED, LA JOLLA, CA 92093 USA
[3] UNIV CALIF SAN DIEGO, DEPT SURG, LA JOLLA, CA 92093 USA
[4] UNIV CALIF SAN DIEGO, DEPT OTOLARYNGOL & NEUROSCI, LA JOLLA, CA 92093 USA
[5] VET AFFAIRS MED CTR, LA JOLLA, CA 92093 USA
[6] SALK INST BIOL STUDIES, NEURONAL STRUCT & FUNCT LAB, SAN DIEGO, CA 92186 USA