Anatomical projection of the cochlea to the cochlear nuclei of the guinea pig.

Abstract

In 16 guinea pigs restricted lesions of the cochlea and the resulting degeneration in the cochlear nerve and in the cochlear nuclei were confirmed by Bodian and Schultze-Gros methods, to study the relationships of central projection of single cochlear turns with the cytoarchitectural areas of the cochlear nucleus complex. The ascending branches of the basal turn terminate in the medial part of the anteroventral cochlear nucleus (AVCN) including the globular cell area, the small spherical cell area and the caudal portion of the large spherical cell area. The descending branches of the basal turn project onto the dorsomedial two-thirds of the posteroventral nucleus (PVCN) with globular cell and octopus cell areas, and terminate in the dorsomedial portion of the central region of the dorsal cochlear nucleus (DCN). Terminals of the apical turn are associated with globular, small spherical and large spherical cells in the ventrolateral part of the AVCN, with globular cells, multipolar cells and a few octopus cells in the ventral PVCN, and with cells of the lateroventral extreme of the central region in the DCN. Lesions of the second and third turns result in degeneration in correspondingly intermediate regions of the cochlear nuclei. There is a predominance of the basal and second turn representation in the three major subdivisions of the cochlear nuclei except the anterior pole of the AVCN.