Journal of Comparative Physiology A

, Volume 162, Issue 5, pp 623–631 | Cite as

Tactile hairs and leg reflexes in wandering spiders: physiological and anatomical correlates of reflex activity in the leg ganglia

  • Jürgen J. Milde
  • Ernst-August Seyfarth
Article

Summary

Intracellular recordings and Lucifer-yellow fillings were used in a wandering spider,Cupiennius salei Keys., to identify central neuronal correlates of local reflex activity in muscle c2, which inserts on the leg coxa. Here we describe related neuronal elements in the hindleg neuromere of the fused, subesophageal-ganglion complex:
  1. 1.

    Projectionsof primary sensory axons excited by hair deflection are confined to ventral parts of the ipsilateral leg-neuromere (Fig. 1); their central terminals end near longitudinal, interganglionic tracts.

     
  2. 2.

    Two identified excitatorymotor neurons for muscle c2 (which is a promotor/adductor of the coxa) are also confined to the ipsilateral (hindleg) ganglion. The dendritic branches and the efferent axonal segment extend in regions well dorsal to the sensory projections (Fig. 2); we found neither morphological nor electrophysiological evidence for direct synaptic contacts between hair afferents and motor neurons (Fig. 3).

     
  3. 3.

    Various types of identifiedinterneurons give responses correlated with the reflex. We classified them, by anatomical criteria, aslocal interneurons confined to the ipsilateral hindleg neuromere (Figs. 4, 5) and asplurisegmental interneurons arborizing in more than one neuromere (Figs. 6, 7, 8).

     

Although detailed electrophysiological tests of functional connections are not available for all these elements, we discuss how the various interneurons identified here may be involved in the local reflex response and in the coordinated, intersegmental reflex behavior that is observed when the unrestrained spider uses all 8 legs to raise its body (see the companion paper by Eckweiler and Seyfarth 1988).

Abbreviation

CNS

central nervous system

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References

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Copyright information

© Springer-Verlag 1988

Authors and Affiliations

  • Jürgen J. Milde
    • 1
  • Ernst-August Seyfarth
    • 2
  1. 1.Zoologisches Institut der UniversitätKöln 41Federal Republic of Germany
  2. 2.Gruppe SinnesphysiologieZoologisches Institut der J.W. Goethe-UniversitätFrankfurt am Main 11Federal Republic of Germany

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