Journal of Comparative Physiology A

, Volume 159, Issue 6, pp 869–878

The development of the static vestibulo-ocular reflex in the Southern Clawed Toad,Xenopus laevis

I. Intact animals
  • E. Horn
  • H. -G. Lang
  • B. Rayer
Article

DOI: 10.1007/BF00603740

Cite this article as:
Horn, E., Lang, H.G. & Rayer, B. J. Comp. Physiol. (1986) 159: 869. doi:10.1007/BF00603740

Summary

In the clawed toad,Xenopus laevis, the static vestibulo-ocular reflex appears in 3 days old tadpoles (developmental stage 42) (Fig. 2). The amplitude and gain of this reflex increase up to stage 52, and then decrease to an almost constant value at stage 60 and older tadpoles (Fig. 3). The most effective roll angle gradually increases during development (Fig. 4).

The size of the sensory epithelia reaches the final value at the end of the premetamorphic period (stage 56) (Fig. 5). The small-cellular medial ventral vestibular nucleus (VVN) reaches its maximal number of neurons before the large-cellular lateral VVN. Cell death is more pronounced in the medial than in the lateral part of the VVN. In the dorsal vestibular nucleus (DVN), the numerical development of the small and large neurons is similar to that in the small-cellular medial and large-cellular lateral portion of the VVN (Fig. 7).

The results demonstrate that labyrinth and oculomotor centres are anatomically connected before the labyrinth and the vestibular nuclei are fully developed. We discuss the possibility that the ciliary polarity pattern of the sensory epithelium is radial during the first period of life, and changes to the vertebrate fan-type pattern during the second week of life. According to the increase of gain during the first three weeks of life, an increase of the spontaneous activity of vestibular neurons may occur during this period.

Abbreviations

α

eye angle

γ

roll angle

α(γ)

response characteristic

A

response amplitude

G

response gain

VOR

vestibulo-ocular reflex

VVN

ventral vestibular nucleus

DVN

dorsal vestibular nucleus

Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • E. Horn
    • 1
  • H. -G. Lang
  • B. Rayer
    • 2
  1. 1.Abteilung für Neurologie, Sektion NeurophysiologieUniversität Ulm, Oberer EselsbergUlmGermany
  2. 2.Institut für Biologie II (Zoologie)RWTH AachenAachenGermany