Topography and cytoarchitecture of the motor nuclei in the brainstem of salamanders
Article first published online: 9 OCT 2004
Copyright © 1988 Alan R. Liss, Inc.
Journal of Comparative Neurology
Volume 278, Issue 2, pages 181–194, 8 December 1988
How to Cite
Roth, G., Nishikawa, K., Dicke, U. and Wake, D. B. (1988), Topography and cytoarchitecture of the motor nuclei in the brainstem of salamanders. J. Comp. Neurol., 278: 181–194. doi: 10.1002/cne.902780203
- Issue published online: 9 OCT 2004
- Article first published online: 9 OCT 2004
- Manuscript Accepted: 23 MAY 1988
- motor neurons;
- feeding behavior;
- cranial nerves;
- horseradish peroxidase
The organization of the motor nuclei of cranial nerves V (including mesencephalic nucleus), VI, VII, IX, and X is described from HRP-stained material (whole mounts and sections) for 25 species representing five families of salamanders, and the general topology of the brainstem is considered. Location and organization of the motor nuclei, cytoarchitecture of each nucleus, and target organs for nuclei and subnuclei are described. The trigeminal nucleus is separated distinctly from the facial and abducens nuclei and consists of two subnuclei. The abducens nucleus consists of two distinct subnuclei, one medial in location, the abducens proper, and the other lateral, the abducens accessorius. The facial nucleus has two subnuclei, and in all but one species it is posterior to the genu facialis. The facial nucleus completely overlaps the glossopharyngeal nucleus and partially overlaps that of the vagus. In bolitoglossine plethodontid salamanders, all of which have highly specialized projectile tongues, the glossopharyngeal and vagus nuclei have moved rostrally to overlap extensively and intermingle with the anterior and posterior subnuclei of the facial nerve. In the bolitoglossines there is less organization of the cells of the brainstem nuclei: dendritic trunks are less parallel and projection fields are wider than in other salamanders. Some aspects of function and development are discussed; comparisons are made to conditions in anurans; and phylogenetic implications are considered.