Journal of Comparative Physiology A

, Volume 167, Issue 4, pp 509–520

Responses of medullary neurons to moving visual stimuli in the common toad

II. An intracellular recording and cobalt-lysine labeling study
  • W. W. Schwippert
  • T. W. Beneke
  • J. P. Ewert
Article

DOI: 10.1007/BF00190821

Cite this article as:
Schwippert, W.W., Beneke, T.W. & Ewert, J.P. J Comp Physiol A (1990) 167: 509. doi:10.1007/BF00190821

Summary

Intracellular recording and labeling of cells from the toad's (Bufo bufo spinosus) medulla oblongata in response to moving visual (and tactual) stimuli yield the following results. (i) Various response types characterized by extracellular recording in medullary neurons were also identified intracellularly and thus assigned to properties of medullary cell somata. (ii) Focussing on monocular small-field and cyclic bursting properties, somata of such neurons were recorded most frequently in the medial reticular formation and in the branchiomotor column but less often in the lateral reticular formation. (iii) Visual object disrimination established in pretectal/tectal networks is increased in its acuity in 4 types of medullary small-field neurons. The excitatory and inhibitory inputs to these neurons evoked by moving visual objects suggest special convergence likely to increase the filter properties. (iv) Releasing conditions, temporal pattern, and refractoriness of cyclic bursting neurons resemble membrane characteristics of vertebrate and invertebrate neurons known to play a role in premotor/motor activity. (v) Integrating functions of medullary cells have an anatomical correlate in the extensive arborizations of their dendritic trees; 5 morphological types of medullary neurons have been distinguished.

Key words

Visuomotor integration Medulla oblongata Intracellular recording and labeling Toad 

Abbreviations

A

stripe moving in antiworm configuration

(W)

moving in worm configuration

S

square

BMC

branchiomotor column

EPSP

excitatory postsynaptic potential

IPSP

inhibitory postsynaptic potential

RetF

medullary reticular formation

RF

receptive field

M neurons

response properties of medullary neurons

T neurons

classes of tectal neurons

TH neurons

classes of thalamic/pretectal neurons

tr.tb.d.

tractus tecto-bulbaris directus

tr.tbs.c.

tractus tecto-bulbaris et spinalis cruciatus

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • W. W. Schwippert
    • 1
  • T. W. Beneke
    • 1
  • J. P. Ewert
    • 1
  1. 1.Abteilung Neurobiologie, Fachbereich Biologie/ChemieUniversität KasselKasselFederal Republic of Germany

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