Synapses involving auditory nerve fibers in primate cochlea.

Abstract

The anatomical mechanisms for processing auditory signals are extremely complex and incompletely understood, despite major advances with the use of EM. A major enigma is the presence in the mammalian cochlea of a double hair cell receptor system. A renewed attempt to discover evidence of synaptic coupling between the 2 systems in the primate [Erythrocebus patas and Macaca mulatta] cochlea, postulated from physiological studies, has failed. In the outer spiral bundle the narrow and rigid clefts seen between pairs of presumptive afferent fibers suggest the possibility of dendro-dendritic interaction confined to the outer hair cell system. The clustering of afferent processes within folds of supporting cells subjacent to outer hair cells is in contrast to the lack of such close associations in the inner hair cell region. The difference reinforces the suggestion of functional interaction of some sort between the outer hair cell afferent nerve processes.