Interaction Between The Utricles And The Horizontal Semicircular Canals Iii. Sectioning Of The Horizontal Ampullar Nerve On One Side And Of The Utricrtlar Nerve On The Other, Followed By Tilting Around The Longitudinal Axis

Abstract

In 20 cats selective sectioning of the horizontal ampullar nerve was performed on one side, and of the utricular nerve on the other. Sectioning of the ampullar nerve caused nystagmus in the contra-lateral direction. This nystagmus either decreased or disappeared completely as a result of the subsequent sectioning of the utricular nerve. Tilting toward the side where the ampullar nerve had been cut resulted in an increase in the previously diminished nystagmus, or caused its reappearance, if it had previously been inhibited. Tilting in the other direction caused no alteration in those cases where inhibition had occurred and total inhibition in those cases where nystagmus had been decreased. Finally, if both utricular nerves were cut there was no alteration in nystagmus during tilting in either direction.