Summary
An attempt is made to identify, under the electron microscope, the climbing fibers of the cerebellum (in the cat) and their synaptic contacts with Purkinje cells and other cortical neurons. — Two kinds of axonal profiles, having synaptic contacts with primary and secondary dendrites of Purkinje neurons, can be recognized: One being terminal fibers densely packed with neurofilaments, having mainly contacts “de passage” with the dendrite surface, with small accumulations of synaptic vesicles at the presynaptic side of the contact. The others are rather knob-shaped contacts filled with synaptic vesicles and poor in neurofilaments. In chronically isolated folia, in which only local neurons and their processes have survived, all filamentous profiles have disappeared while vesicular ones are not appreciably reduced in number. It is inferred from this, that the neurofilamentous profiles correspond to climbing fibers, whereas the vesicular ones could be the endings of outer stellate axons, recurrent Purkinje axon collaterals, or ascending basket axon collaterals. — Similar two kinds of axon-terminal profiles are found in synaptic contact with Golgi and basket cell bodies. As in chronically isolated folia only the vesicular profiles survive, it is inferred that the climbing fiber has axo-somatic terminals on Golgi cells and basket cells as well. Previous information of this kind, gained with the light microscope and with degeneration studies, is thus substantiated with the aid of the electron microscope. The vesicular presynaptic profiles on Golgi and basket neurons are in the first case certainly and in the second with high probability endings of recurrent Purkinje axon collaterals. — The few axosomatic synapses found on outer stellate neurons may also be terminals of climbing fibers, but degeneration evidence for this is not conclusive. — The observations are summarized and evaluated from the functional point of view in a diagram, with consideration to recent physiological information on the function of climbing fibers.
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Andersen, P., J.C. Eccles and P.E. Voorhoeve: Inhibitory synapses on somas of Purkinje cells in the cerebellum. Nature (Lond.) 199, 655–656 (1963).
Brodal, A.: In Handbuch der Mikroskopischen Anatomie des Menschen, Bd. 4, T. 8, S. 132. Berlin-Göttingen-Heidelberg: Springer 1958.
Cajal, R. y S.: Sobre las fibras nerviosae de la capá molecular der cerebello. Rev. trimest. micrograf. 1, 1 (1888).
Carrea, B.M.E., M. Reissig and F.A. Mettler: The climbing fibers of the simian and feline cerebellum. J. comp. Neurol. 87, 321–365 (1947).
Eccles, J.C., R. Llinás and K. Sasaki: Excitation of cerebellar Purkinje cells by the climbing fibers. Nature (Lond.) 203, 245–246 (1964).
—: Golgi cell inhibition in the cerebellar cortex. Nature (Lond.) 204, 1265–1266 (1964).
Fox, C.A., and J.W. Barnard: A quantitative study of the Purkinje cell dendritic branchlets and their relationship to afferent fibers. J. Anat. 91, 299–313 (1957).
Frezik, J.: Associative connections established by Purkinje axon collaterals between different parts of the cerebellar cortex. Acta morph. Acad. Sci. hung. 12, 9–13 (1963).
Gray, E.G.: Axosomatic and axodendritic synapses of the cerebral cortex: an electron microscopy study. J. Anat. 93, 420 (1959).
Hámori, J.: Identification in the cerebellar isles of Golgi II axon endings by aid of experimental degeneration. IIIrd European Regional Conference on Electron Mior., Prague 2, 291–292 (1964).
—, and J. Szentágothai: The “crossing-over” synapse: an electron microscope study of the molecular layer in the cerebellar cortex. Acta biol. Acad. Sci. hung. 15, 95–117 (1964).
—: The Purkinje cell baskets: ultrastructure of an inhibitory synapse. Acta biol. Acad. Sci. hung. 15, 465–479 (1965).
Herndon, R.M.: The fine structure of the Purkinje cell. J. Cell Biol. 18, 167–180 (1963).
Ito, M., N. Kawai and M. Udo: The origin of cerebellar-induced inhibition and facilitation in the neurones of Deiter's and intracerebellar nuclei. Abstracts of papers of the XXIII. Int. Congr. Physiol. Tokyo, Japan, 421 (1965).
Miskolczy, D.: Über die Endigungsweise der spino-cerebellaren Bahnen. Z. Anat. Entwickl.-Gesch. 96, 537–542 (1931).
Reynolds, E.S.: The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J. Cell Biol. 17, 208–212 (1963).
Rosiello, L.: Sull'origine delle fibre muschiose del cerveleto. Riv. Neurol. 10, 437–455 (1937).
Scheibel, M.E., and A.B. Scheibel: Observations on the intracortical relations of the climbing fibers of the cerebellum. A Golgi study. J. comp. Neurol. 101, 733–764 (1954).
Schimert (Szentágothai), J.: Die sekundäre Degeneration der Kollateralen und Endbäumchen im Zentralnervensystem. Anat. Anz. Erg.-H. 87, 312–319 (1939).
Snider, R.S.: Alterations which occur in mossy terminals of the cerebellum following transection of the brachium pontis. J. comp. Neurol. 64, 417–431 (1936).
Szentágothai, J.: The anatomical basis of synaptic transmission of excitation and inhibition in motoneurons. Acta morph. Acad. Sci. hung. 8, 287–309 (1958).
Szentágothai, J. On synaptology of the cerebral cortex in. In: Structure and Function of the Nervous System, ed. S.A. Sarkisov. Moscow 1962 (in russian).
—: The use of degeneration methods in the investigation of short neuronal connections. In: Progress in Brain research, vol. 14, 1–32, eds. M. Singer and J.P. Schadé. Amsterdam-London-New York: Elsevier 1965.
—, and K. Rajkovits: Über den Ursprung der Kletterfasern des Kleinhirn. Z. Anat. Ent-wickl.-Gesch. 121, 130–141 (1959).
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Hámori, J., Szentágothai, J. Identification under the electron microscope of climbing fibers and their synaptic contacts. Exp Brain Res 1, 65–81 (1966). https://doi.org/10.1007/BF00235210
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DOI: https://doi.org/10.1007/BF00235210