Summary
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1.
Every afferent fibre of the lateral line divides into 2 collaterals upon reaching the stitch (neuromast group). Each collateral innervates a part of the stitch, and sends branches to each individual neuromast (Fig. 3) in its region.
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2.
In the area of a stitch the nodes of RANVIER of the afferent and efferent fibres only occur at the branching points. The myelin ends at the basement membrane of the neuromasts (Fig. 5).
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3.
Simultaneous extracellular recordings of afferent activity in two neuromasts show that each neuromast has one impulse generation site. This is situated distal to the myelinated region of the fibre (Figs. 7, 9–11).
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4.
In any one stitch the afferent impulses generated by a single neuromast propagate orthodromically and antidromically within the collaterals and branches of the fibre.
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References
Adrian, E.D., Zotterman, Y.: The impulses produced by sensory-nerve-endings. Part 2. The response of a single end-organ. J. Physiol. (Lond.)61, 151–171 (1926)
Burkhardt, D.: Die Übertragereigenschaften elektrophysiologischer Versuchsanordnungen. Z. Biol.109, 297–324 (1957)
Dijkgraaf, S.: The funktioning and significance of the lateral-line organs. Biol. Rev.38, 51–105 (1963)
Eagles, J.P., Purple, R.L.: Afferent fibres with multiple encoding sites. Brain Res.77, 187–193 (1974)
Edwards, C., Ottoson, D.: The site of impulse initiation in a nerve cell of a crustacean stretch receptor. J. Physiol. (Lond.)143, 138–148 (1958)
Eyzaguirre, C., Kuffler, S.W.: Processes of excitation in the dendrites and in the soma of single isolated sensory nerve cells of the lobster and crayfish. J. gen. Physiol.39, 87–119 (1955)
Flock, A.: Ultrastructure and function in the lateral line organs. In: Lateral line detectors (ed. P. Cahn). Bloomington: Indiana Univ. Press 1967
Florey, E., Florey, E.: Microanatomy of the abdominal stretch receptors of the crayfish (Astacus fluviatilis L.). J. gen. Physiol.39, 69–85 (1955)
Floyd, K., Morrison, J.F.B.: Interactions between afferent impulses within a peripheral receptive field. J. Physiol. (Lond.)238, 62 P (1974)
Gesteland, R.C., Howland, B., Lettvin, I.Y., Pitts, W.H.: Comments on microelectrodes. Proc. IRE.47, 1856–1862 (1959)
Görner, P.: Beitrag zum Bau und zur Arbeitsweise des Seitenlinienorgans vonXenopus laevis. Verh. dtsch. zool. Ges. Saarbrücken, 193–198 (1961)
Görner, P.: Untersuchungen zur Morphologie und Elektrophysiologie des Seitenlinienorgans vom Krallenfrosch (Xenopus laevis Daudin). Z. vergl. Physiol.47, 316–338 (1963)
Görner, P.: Independence of afferent activity from efferent activity in the lateral line organ ofXenopus laevis Daudin. In: Lateral line detectors (ed. P.H. Cahn). Bloomington: Indiana Univ. Press 1967
Harris, G., Flock, A.: Spontaneous and evoked activity from theXenopus laevis lateral line. In: Lateral line detectors (ed. P.H. Cahn). Bloomington: Indiana Univ. Press 1967
Harris, G., Frishkopf, L., Flock, A.: Receptor potentials from hair cells of the lateral line. Science167, 76–79 (1970)
Harris, G., Milne, D.C.: Input-output characteristics of the lateral-line sense organ. J. acoust. Soc. Amer.40, 32–42 (1966)
Horch, K.W., Whitehorn, D., Burgess, P.R.: Impulse generation in type I cutaneous mechanoreceptors. J. Neurophysiol.37, 267–281 (1974)
Kennedy, D.: Input and output connections of single arthropod neurons. In: Physiological and biochemical aspects of nervous integration (ed. F.D. Carlson), pp. 285–306. Englewood Chuffs: Prentice Hall 1968
Lindblom, U.: Excitability and functional organization within a peripheral tactile unit. Acta physiol. scand., Suppl.153, 44, 1–84 (1958)
Lindblom, U., Tapper, D.N.: Integration of impulse activity in a peripheral sensory unit. Exp. Neurol.15, 63–69 (1966)
Macdonald, J.A., Brodwick, M.S.: Inhibition in branched afferent neurons of the bullfrog tongue. J. comp. Physiol.87, 293–316 (1973)
Murray, M.J.: Conductile trees: Obtaining structural and functional information from endpoint measurements. J. theor. Biol.43, 113–132 (1974)
Murray, M.J., Capranica, R.R.: Spike generation in the lateral-line afferents ofXenopus laevis: Evidence favoring multiple sites of initiation. J. comp. Physiol.87, 1–20 (1973)
Murray, R.W.: The lateral-line organs and their innervation inXenopus laevis. Quart. J. micr. Sci.96, 351–361 (1955)
Murray, R.W.: The thermal sensitivity of the lateralis organs ofXenopus. J. exp. Biol.33, 798–805 (1956)
Pabst, A.: A simple method for use with tungsten microelectrodes for the localization of recording sites. Pflügers Arch.339, 355–358 (1973)
Pabst, H., Kennedy, D.: Cutaneous mechanoreceptors influencing motor output in the crayfish abdomen. Z. vergl. Physiol.57, 190–208 (1967)
Palade, G.: A study of fixation for electron microscopy. J. exp. Med.95, 285–298 (1952)
Romeis, B.: Mikroskopische Technik. 16. Aufl. München-Wien: R. Oldenbourg 1968
Russell, I.: The role of the lateral-line efferent system inXenopus laevis. J. exp. Biol.54, 621–641 (1971)
Schmidt, R.: Amphibian acoustico-lateralis efferents. J. cell. comp. Physiol.65, 155–162 (1965)
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I thank Prof. Dr. Peter Görner and Dr. Simon Laughlin for their helpful suggestions and Mrs. Astrid Klawitter for technical assistance
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Pabst, A. Number and location of the sites of impulse generation in the lateral-line afferents ofXenopus laevis . J. Comp. Physiol. 114, 51–67 (1977). https://doi.org/10.1007/BF00656808
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DOI: https://doi.org/10.1007/BF00656808