Summary
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1.
Postsynaptic potentials of various auditory interneurons were recorded intracellularly in the metathoracic ganglion of the locust. Although the sound stimulus consisted of bursts of pure tones (20 or 100 ms duration), only a minority of intracellular responses (8 out of 43) exhibited simply configurated depolarizing potentials (Fig. 2a, b). Most responses were composed of excitatory and inhibitory postsynaptic potentials (Fig. 2c-e) with different temporal interactions between EPSP and IPSP. Thus the multifold spike patterns, known in principle from previous extracellular recordings, can be explained.
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2.
In the neuron of Fig. 3 a the threshold curves of EPSP and IPSP differ significantly in the frequencyintensity field. Based on a comparison with previous findings on receptors and one thoracic interneuron (Rehbein et al. 1974), a model for synaptic connectivity is proposed, although detailed morphological data are not available.
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3.
The degree of EPSP- and IPSP-interaction depends strongly on sound direction. The ipsilaterally generated excitation can be totally eliminated when the contralateral ear is more strongly stimulated (Figs. 4, 5). Two different modes of temporal interaction between EPSP and IPSP can be detected: on the one hand — if both potentials appear — the inhibition follows the excitation. Thus the resulting spiking activity is modified without changing the latency of the corresponding response (Figs. 4, 6). On the other hand the inhibition precedes excitation (Fig. 5), which in addition influences the initial phase (latency) of the response. These data indicate the existence of an underlying synaptic mechanism for previous extracellular findings (see Mörchen 1980).
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Abbreviations
- EPSP :
-
excitatory postsynaptic potential
- IPSP :
-
inhibitory postsynaptic potential
References
Adam LJ (1969) Neurophysiologie des Hörens und Bioakustik einer Feldheuschrecke (Locusta migratoria). Z Vergl Physiol 63:227–289
Boyan GS (1980) Auditory neurones in the brain of the cricketGryllus bimaculatus (De Geer). J Comp Physiol 140:81–93
Elsner N, Popov AV (1978) Neuroethology of acoustic communication. Adv Insect Physiol 13:229–335
Huber F, Wohlers DW, Moore TE (1980) Auditory nerve and interneurone responses to several species of cicadas. Physiol Entomol 5:25–45
Kalmring K (1971) Akustische Neuronen im Unterschlundganglion der WanderheuschreckeLocusta migratoria. Z Vergl Physiol 75:95–110
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 104:103–141
Kalmring K, Rheinlaender J, Rehbein HG (1972a) Akustische Neuronen im Bauchmark der WanderheuschreckeLocusta migratoria. Z Vergl Physiol 76:314–332
Kalmring K, Rheinlaender J, Römer H (1972b) Akustische Neuronen im Bauchmark vonLocusta migratoria. J Comp Physiol 80:325–352
Levine RB, Murphey RK (1980) Loss of inhibitory synaptic input to cricket sensory interneurons as a consequence of partial deafferentation. J Neurophysiol 43:383–394
Michelsen A (1971) The physiology of the locust ear. Z Vergl Physiol 71:49–62
Mörchen A (1980) Spike count and response latency. Two basic parameters encoding sound direction in the CNS of insects. Naturwissenschaften 67:469
Mörchen A, Rheinlaender J, Schwartzkopff J (1978) Latency shift in insect auditory nerve fibres. A neural time cue of sound direction. Naturwissenschaften 65:656–657
Pearson KG, Goodman CS (1979) Correlation of variability in structure with variability in synaptic connections of an identified interneuron in locusts. J Comp Neurol 184:141–163
Pearson KG, Heitler WJ, Steeves JD (1980) Triggering of locust jump by multimodal inhibitory interneurons. J Neurophysiol 43:257–278
Rehbein HG (1973) Experimentell-anatomische Untersuchungen über den Verlauf der Tympanalnervenfasern im Bauchmark von Feldheuschrecken, Laubheuschrecken und Grillen. Verh Dtsch Zool Ges 66:184–189
Rehbein HG (1976) Auditory neurons in the ventral nerve cord of the locust: Morphological and functional properties. J Comp Physiol 110:233–250
Rehbein HG, Kalmring K, Römer H (1974) Structure and function of acoustic neurons in the ventral nerve cord ofLocusta migratoria. J Comp Physiol 95:263–280
Rheinlaender J, Römer H (1980) Bilateral coding of sound direction in the CNS of the bushcricketTettigonia viridissima L. (Orthoptera, Tettigoniidae). J Comp Physiol 140:101–111
Römer H (1975) Die Informationsverarbeitung tympanaler Rezeptorelemente vonLocusta migratoria. Dissertation, Univ Bochum
Römer H (1976) Die Informationsverarbeitung tympanaler Rezeptorelemente vonLocusta migratoria (Acrididae, Orthoptera). J Comp Physiol 109:102–122
Suga N, Katsuki Y (1961) Central mechanisms of hearing in insects. J Exp Biol 38:545–558
Wiese K (1978) Negative Rückkoppelung in der akustischen Bahn vonGryllus bimaculatus als Grundlage temporalen Filterns. Verh Dtsch Zool Ges: 168
Wohlers DW, Huber F (1978) Intracellular recording and staining of cricket auditory interneurons (Gryllus campestris L.,Gryllus bimaculatus De Geer). J Comp Physiol 127:11–28
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This work was supported by Sonderforschungsbereich ‘Bionach SFB 114’ and by a personal grant to J.R. (Rh 15/1-1) from the Deutsche Forschungsgemeinschaft. We especially appreciate the critical discussion of some results by Dr. J. Deitmer and the advice from Prof. Dr. J. Schwartzkopff in this project. We thank I.W. Green for revising the manuscript.
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Römer, H., Rheinlaender, J. & Dronse, R. Intracellular studies on auditory processing in the metathoracic ganglion of the locust. J. Comp. Physiol. 144, 305–312 (1981). https://doi.org/10.1007/BF00612562
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DOI: https://doi.org/10.1007/BF00612562