Journal of Comparative Physiology A

, Volume 155, Issue 2, pp 249–262 | Cite as

Morphology and physiology of auditory interneurons in the metathoracic ganglion of the locust

  • Heiner Römer
  • Volker Marquart


  1. 1.

    Auditory interneurons in the metathoracic ganglion of the locust were characterized by their intracellularly recorded responses to sound stimuli, and by their morphology as revealed in sectioned preparations of single neurons injected with Lucifer Yellow. Accordingly, nine interneurons were identified as either local, bisegmental, ascending or T-neurons (Figs. 2–6).

  2. 2.

    All cells possess arborizations within one or both sides of a prominent area of fine neuropil (frontal auditory neuropil), but the degree of overlap with the endings of tympanic afferents is different. For 2 ascending units (AN2, AN3) there is no overlap at all, indicating that they are interneurons of higher order.

  3. 3.

    Two neurons, SN1 and TN1, were found with only excitatory input to low frequency sound, and their tuning reflected that one of low frequency receptor fibres. In contrast, the response of all other neurons to low frequency stimuli was more complex, consisting of excitatory and inhibitory synaptic potentials. The neuronal circuitry which might underlie such physiological behaviour is discussed.

  4. 4.

    Recordings made from different parts of individual neurons enabled the sites of synaptic input and output to be localized. The postsynaptic dendrites of the interneurons appear to correspond to smooth endings in contrast to the beaded appearance of the presumptive presynaptic terminals (Fig. 8).

  5. 5.

    The results include descriptions of auditory ‘sister-neurons’ (Fig. 6) which have a similar morphology and of ‘twin-neurons’ (Fig. 7), which, using our present physiological and morphological criteria, cannot reliably be distinguished one from another. The problem that arises from such doubling of cells for the concept of identified units is discussed.



Presynaptic Terminal Excitatory Input Sound Stimulus Lucifer Yellow Synaptic Potential 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Adam LJ (1969) Neurophysiologie des Hörens und Bioakustik einer Feldheuschrecke (Locusta migratoria). Z Vergl Physiol 63:227–289Google Scholar
  2. Altman JS, Kien J (1984) The anatomical basis for intersegmental and bilateral co-ordination in locusts. SEB Seminar Series (in press)Google Scholar
  3. Boyan GS (1984) Neural mechanisms of auditory information processing by identified interneurons in Orthoptera. J Insect Physiol 30:27–41Google Scholar
  4. Čokl A, Kalmring K, Wittig H (1977) The response of auditory ventral-cord neurons ofLocusta migratoria to vibration stimuli. J Comp Physiol 120:161–172Google Scholar
  5. Dörrscheidt GJ, Rheinlaender J (1980) Computer generation of sound models for behavioural and neurophysiological experiments in insects. J Insect Physiol 26:717–727Google Scholar
  6. Eibl E, Huber F (1979) Central projections of tibial sensory fibres within the three thoracic ganglia of crickets (Gryllus campestris L.,Gryllus bimaculatus De Geer). Zoomorphologie 92:l-17Google Scholar
  7. Goodman CS (1974) Anatomy of locust ocellar interneurons: constancy and variability. J Comp Physiol 95:185–201Google Scholar
  8. Goodman CS (1976a) Constancy and uniqueness in a large population of small interneurons. Science 193:502–504Google Scholar
  9. Goodman CS, Pearson KG, Heitler WJ (1979) Variability of identified neurons in grasshoppers. Comp Biochem Physiol 64:455–462Google Scholar
  10. Kalmring K (1975) The afferent auditory pathway in the ventral cord ofLocusta migratoria (Acrididae). I. Synaptic connectivity and information processing among the auditory neurons in the ventral cord. J Comp Physiol 104:103–141Google Scholar
  11. Kalmring K, Rheinlaender J, Rehbein HG (1972a) Akustische Neuronen im Bauchmark der WanderheuschreckeLocusta migratoria. Z Vergl Physiol 76:314–332Google Scholar
  12. Kalmring K, Rheinlaender J, Römer H (1972b) Akustische Neuronen im Bauchmark vonLocusta migratoria. J Comp Physiol 80:325–352Google Scholar
  13. McIlwain JT, Creutzfeld OD (1967) Microelectrode study of synaptic excitation and inhibition in the lateral geniculate nucleus of the cat. J Neurophysiol 30:1–21Google Scholar
  14. Michelsen A (1971) The physiology of the locust ear. III. Acoustical properties of the intact ear. Z Vergl Physiol 71:102–128Google Scholar
  15. Moiseff A, Hoy R (1983) Sensitivity to ultrasound in an identified auditory interneuron in the cricket: a possible neuronal link to phonotactic behavior. J Comp Physiol 152:155–167Google Scholar
  16. Rehbein HG (1973) Experimentell-anatomische Untersuchungen über den Verlauf der Tympanalnervenfasern im Bauchmark von Feldheuschrecken, Laubheuschrecken und Grillen. Verh Dtsch Zool Ges 66:184–189Google Scholar
  17. Rehbein HG (1976) Auditory neurons in the ventral cord of the locust: morphological and functional properties. J Comp Physiol 110:233–250Google Scholar
  18. Rehbein HG, Kalmring K, Römer H (1974) Structure and function of acoustic neurons in the thoracic ventral cord ofLocusta migratoria. J Comp Physiol 95:263–280Google Scholar
  19. Rheinlaender J (1984) Das akustische Orientierungsverhalten von Heuschrecken, Grillen und Fröschen: Eine vergleichende neuro- und verhaltensphysiologische Untersuchung. Habilitationsschrift, BochumGoogle Scholar
  20. Rheinlaender J, Römer H (1980) Bilateral coding of sound direction in the CNS of the bushcricketTettigonia viridissima L. (Orthoptera, Tettigoniidae). J Comp Physiol 140:101–111Google Scholar
  21. Richardson KC, Jarett L, Finke EH (1960) Embedding in epoxy resins for ultrathin sectioning in electron microscopy. Stain Technol 35:313–323Google Scholar
  22. Robertson RM, Pearson KG (1983) Interneurons in the flight system of the locust: distribution, connections, and resetting properties. J Comp Neurol 215:33–50Google Scholar
  23. Römer H (1976) Die Informationsverarbeitung tympanaler Rezeptorelemente vonLocusta migratoria (Acrididae, Orthoptera). J Comp Physiol 109:102–122Google Scholar
  24. Römer H, Dronse R (1982) Synaptic mechanisms of monaural and binaural processing in the locust. J Insect Physiol 28:365–370Google Scholar
  25. Römer H, Rheinlaender J (1983) Electrical stimulation of the tympanal nerve as a tool for analysing the responses of auditory interneurons in the locust. J Comp Physiol 152:289–296Google Scholar
  26. Römer H, Rheinlaender J, Dronse R (1981) Intracellular studies on auditory processing in the metathoracic ganglion of the locust. J Comp Physiol 144:305–312Google Scholar
  27. Spurr AR (1969) A low-viscosity epoxy resin embedding medium for electron microscopy. J Ultrastruct Res 26:31–43Google Scholar
  28. Steeves JD, Pearson KD (1983) Variability in the structure of an identified interneuron in isogenic clones of locusts. J Exp Biol 103:47–54Google Scholar
  29. Stewart WW (1978) Functional connections between cells as revealed by dye-coupling with a highly fluorescent naphthalimide tracer. Cell 14:741–759Google Scholar
  30. Tyrer NM, Gregory GE (1982) A guide to the neuroanatomy of locust suboesophageal and thoracic ganglia. Phil Trans R Soc Lond 297:91–123Google Scholar
  31. Tyrer NM, Shaw MK, Altman JS (1980) Intensification of cobalt-filled neurons in sections (light and electron microscopy). In: Strausfeld NJ, Miller TA (eds) Neuroanatomical techniques, Springer, Berlin Heidelberg New York, pp 431–444Google Scholar
  32. Wohlers DW, Huber F (1978) Intracellular recording and staining of cricket auditory interneurons (Gryllus campestris L.,Gryllus bimaculatus De Geer). J Comp Physiol 127:11–28Google Scholar
  33. Wohlers DW, Huber F (1982) Processing of sound signals by six types of neurons in the prothoracic ganglion of the cricket,Gryllus campestris L. J Comp Physiol 146:161–173Google Scholar

Copyright information

© Springer-Verlag 1984

Authors and Affiliations

  • Heiner Römer
    • 1
  • Volker Marquart
    • 1
  1. 1.Lehrstuhl für Allgemeine ZoologieRuhr-UniversitätBochum 1Germany

Personalised recommendations