Distribution of Efferent Nerve Endings in the Organ of Corti: Their Graphic Reconstruction in Cochleae by Localization of Acetylcholinesterase Activity

Abstract

The efferent innervation of the organ of Corti was studied in normal cats. The efferent nerve endings were visualized in serial frozen sections by demonstrating specific AChE activity in them. Innervation of the outer hair cells gradually decreased in the apical direction to the point where no efferent innervation was present; this was more evident in the outer row than in the inner row of outer hair cells. AChE activity was poorly visualized around the inner hair cells, but was very strong in the inner spiral bundle of nerve fibers throughout the cochlea. These observations are in agreement with pertinent electron microscopic and electrophysiological data.