This grant continues to provide varying degrees of individual and core support for a variety of projects related to the cochleo-vestibular system in animals and the human. Specific topics include anterograde transport of horseradish peroxidase into frog neurons treated with DAB; the study of the ultra structure of commisural fibers of the vestibular nuclei of squirrel monkeys. This grant also provides support for studying the diseases of human temporal bones. Two new studies are supported which relate to the physiology of the sacculus and the INVITRO and INVIVO analysis of gentamicin -carbenicillin complex as possible ototoxic agents in animals and man.