Topography and cytoarchitecture of the motor nuclei in the brainstem of salamanders

Gerhard Roth, Kiisa Nishikawa, Ursula Dicke, David B. Wake

Research output: Contribution to journalArticle

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Abstract

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.

Original languageEnglish (US)
Pages (from-to)181-194
Number of pages14
JournalJournal of Comparative Neurology
Volume278
Issue number2
DOIs
StatePublished - Dec 8 1988
Externally publishedYes

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Keywords

  • cranial nerves
  • feeding behavior
  • horseradish peroxidase
  • motor neurons

ASJC Scopus subject areas

  • Neuroscience(all)

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