The central projections of intracellularly labeled auditory nerve fibers in cats
Article first published online: 9 OCT 2004
Copyright © 1984 Alan R. Liss, Inc.
Journal of Comparative Neurology
Volume 229, Issue 3, pages 432–450, 1 November 1984
How to Cite
Fekete, D. M., Rouiller, E. M., Liberman, M. C. and Ryugo, D. K. (1984), The central projections of intracellularly labeled auditory nerve fibers in cats. J. Comp. Neurol., 229: 432–450. doi: 10.1002/cne.902290311
- Issue published online: 9 OCT 2004
- Article first published online: 9 OCT 2004
- Manuscript Accepted: 27 JUN 1984
- auditory nerve;
- cochlear nucleus;
- primary afferents
The central projections of physiologically characterized auditory nerve fibers were studied in the cochlear nuclei of adult cats after intracellular staining with horseradish peroxidase (HRP). This technique consistently labels only the type I spiral ganglion neurons which contact inner hair cells in the cochlea (Liberman and Oliver, '84). The central axon of each type I neuron bifurcates in the cochlear nucleus to form an ascending branch and a descending branch. The characteristic frequency (CF) of a fiber corresponds to the dorsoventral position of these major branches and their collateral ramifications within the nucleus. Fibers of low CFs are distributed ventrally, and fibers of increasing CF are distributed progressively more dorsally. In some cases, the collateral branches deviate from this tonotopic arrangement, particularly in (1) the octopus cell region of the posteroventral cochlear nucleus, (2) the zone of bifurcations of the auditory nerve fibers, and (3) the anterior, dorsal, and lateral margins of the ventral cochlear nucleus. Spontaneous discharge rate (SR) is related to the complexity of the axon arbor, especially along the ascending branch. Fibers of low and medium SR exhibit more axonal branch points and longer collateral lengths than do those with high SR. Six of 37 labeled fibers fail to innervate the dorsal cochlear nucleus, a feature apparently unrelated to CF or SR.