On the changes in histological structure and electrical response of the cochlea of the cat following section of the VIIIth nerve

Abstract

According to Witmaack (1911), division of the VIIIth nerve in the cat results in widespread degeneration of the cochlear neurones peripheral to the point of section; the morphological integrity of all other cochlear elements being maintained. These findings have been confirmed by later observers (Kaida 1931; Hallpike and Rawdon-Smith 1934 b ), who have in addition shown that these results require for their production the avoidance of damage to the cochlear vessels, which is found to bring about a generalized necrosis of the contents of the internal ear. A study of the electrical response of the internal ear (cochlear component of the Wever and Bray phenomenon) found to occur in the cochlea of a cat denervated in the manner described, has been the subject of a previous publication (Hallpike and Rawdon-Smith 1934 b ). In this, absence of electrical response was found to occur in a cochlea morphologically normal apart from the elimination of the neural elements. The results of a further series of observations upon these lines are now available and form the subject of the present paper.