Deafferentated vestibular nerve

Abstract

Contrary to the cochlear branch of the VIIIth nerve, the vestibular branch does not degenerate quickly in the squirrel monkey after the end organs are surgically removed. This surgical procedure is favored by some investigators who advocate that removal of the vestibular receptors does eventually lead to the death of the nerve. Others think that the neurons of the vestibular ganglion can regenerate and contribute to partial reoccurrence of the symptoms the patient had before surgery. Thus, this problem remains unsettled. We are presently studying the vestibular nerve and ganglia of the squirrel monkey (Saimiri sciureus) in order to examine the fate of the surviving neurons, and the changes that these cells undergo after labyrinthectomy. Animals were anesthetized, perfused intracardially and the specimens were processed for transmission electron microscopy (TEM) as previously described. For light microscopy (LM), some specimens were embedded in JB-4 plastic, cut serially at 5 micra and stained with 0.2% toluidine blue and 0.1% basic fuchsin in 25% alcohol.