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  • 1
    Electronic Resource
    Electronic Resource
    The recurrent collaterals of Purkinje cell axons: A correlated study of the rat's cerebellar cortex with electron microscopy and the Golgi method (1971)
    Springer
    Anatomy and embryology 134 (1971), S. 200-234 
    Details
    ISSN: 1432-0568
    Keywords: Cerebellar cortex ; Purkinje cell ; Axon ; Recurrent collateral ; History ; Synapses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Each Purkinje cell axon with its recurrent collaterals occupies a roughly triangular space in the folium, apex pointed towards the white matter and base against the Purkinje cell layer. The axon is smooth initially but develops distensions that become more obvious at twists and turns and at points where collaterals originate. These thin, finely beaded collaterals make characteristic acute angles with the axon from which they issue. The collaterals bifurcate further, their terminal branches becoming more varicose, intertwining with each other to form plexuses in the molecular and granular layers. These fiber plexuses are found in three locations: (1) the recurrent collateral plexus in the granular layer which synapses with dendrites and somata of deep Golgi II neurons; (2) the profuse infraganglionic plexus, boutons of which terminate in relation with the somata and dendrites of Purkinje cells and Lugaro cells, in addition to participating in other complex synaptic arrangements in the neuropil; (3) the sparse supraganglionic plexus which forms synapses with dendrites of Purkinje cells and occasionally with basket cells. In electron micrographs, terminals belonging to recurrent collaterals contain a mixture of neurofilaments, microtubules, and slender mitochondria with a loose array of flat, elliptical, and round synaptic vesicles embedded in a dark filamentous matrix. It is usual to find a cluster of boutons on the postsynaptic surface. Each synapse consists of several separate macular junctional complexes. The synaptic cleft is widened and contains a dense fibrous material while both pre- and postsynaptic components have very shallow, symmetrical filamentous densities adherent to the cytoplasmic surfaces of the membranes. It is suggested that recurrent collaterals from axons of Purkinje cells may provide a rapid monosynaptic feed-back mechanism for inhibitory control of Purkinje cell responses. These collaterals may also participate in a slower positive feed-forward circuit or resetting mechanism involving at least two synapses. The existence of this circuit is indicated by synapses on deep Golgi II neurons. The inhibition of Golgi II cells may depress their inhibitory activity on surrounding granule cells, thus resetting the mechanism for the subsequent responses to excitatory afferent input. Recurrent collateral inhibition also may aid in the disinhibition of Purkinje cells through the depression of basket cell activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519300
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  • 2
    Electronic Resource
    Electronic Resource
    The synapse en marron between Golgi II neurons and mossy fibers in the rat's cerebellar cortex (1971)
    Springer
    Anatomy and embryology 133 (1971), S. 274-287 
    Details
    ISSN: 1432-0568
    Keywords: Cerebellum ; Cytology ; Synapses ; Mossy fibers ; Glomeruli ; Golgi II neurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Mossy fibers engage in synapses en marron with the somata of some Golgi II cells. These synapses resemble in all particulars the synapses en marron made by climbing fibers except for the distinctive characteristics of the presynaptic terminal. The mossy fiber, with its axial stream of neurofilaments and mitochondria and its loose aggregations of round synaptic vesicles, makes an extensive contact with the wrinkled surface of the Golgi II perikaryon. Synaptic complexes are confined to the depths and sides of the furrows in the Golgi cell. The free side of the mossy fiber terminal often articulates with large numbers of granule cell dendrites, an arrangement similar to that found in ordinary glomeruli. These synaptic connections may be interpreted in the light of the physiological evidence that Golgi II cells inhibit granule cells that are not strongly activated by mossy fibers. Since each granule cell receives four to six mossy fibers, strong activation may require either a selected frequency pattern or synchrony of several inputs. The collateral inhibition indirectly evoked by the same mossy fiber via Golgi II cells would suppress those granule cells not receiving concurrent excitation from other mossy fibers or the favored pattern of excitation. In contrast, granule cells simultaneously activated by other mossy fibers would not be inhibited but would send impulses to the molecular layer. Thus, the glomerulus would behave as a filter that increases the signal-to-noise ratio of the excitatory input to the Purkinje cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519303
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  • 3
    Electronic Resource
    Electronic Resource
    Tendril and glomerular collaterals of climbing fibers in the granular layer of the rat's cerebellar cortex (1971)
    Springer
    Anatomy and embryology 133 (1971), S. 247-273 
    Details
    ISSN: 1432-0568
    Keywords: Cerebellar cortex ; Cytology ; Climbing fibers ; Collaterals ; Glomeruli ; Synapses ; Granular layer ; Purkinje cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rapid Golgi preparations show that two kinds of collaterals issue from the climbing fiber in its course through the granular layer. The first resembles the tendrils found in the molecular layer and consists of globose varcosities connected by a very fine thread. In electron micrographs these varicosities in the granular layer contain dense aggregates of round synaptic vesicles at least 520 Å in diameter and the connecting threads contain numerous microtubules. The varicosities synapse on the somata of Golgi II cells and on the shafts of dendrites belonging to both Golgi II and granule cells. The second type of collateral emerges from the main stem of the climbing fiber as a stout branch that sprays out abruptly into a large efflorescence. In electron micrographs this terminal appears as the central stellate structure in a glomerulus and is packed with round synaptic vesicles like those in the tendril varicosities. Granule cell dendrites encircle the terminal and occasionally synapse with it. Often the terminal in the glomerulus also forms an extensive junction—a synapse en marron—with the some of Golgi II cell. In this region the surface of the cell is wrinkled like a Spanish chestnut and the glomerular terminal is reciprocally ridged and furrowed to match. Synaptic complexes occur only in the furrows of the cell surface. A broad subsynaptic zone is filled with a fine filamentous matrix. This study provides the first morphological identification and description of climbing fiber terminations in the granular layer, the existence of which has been suggested by earlier Golgi studies and postulated by neurophysiologists. The fact that climbing fibers synapse on both granule cells and Golgi II cells complicates the analysis of the way in which the cerebellar cortex operates, because these two cells have postsynaptic effects of opposite sign. The climbing fiber is known to evoke a complex discharge from the Purkinje cell, consisting of a large primary spike and smaller secondary potentials. It is suggested that when a climbing fiber volley traverses the granular layer, the granule cells on which it synapses are induced to excite stellate and basket cells in the molecular layer which in their turn inhibit the secondary spikes of the climbing fiber response in the Purkinje cell. Meanwhile the Golgi II cells, stimulated by the same climbing fiber volley, suppress the granule cells and thus transsynaptically limit the duration of the inhibitory effects exerted by the interneurons in the molecular layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519302
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  • 4
    Electronic Resource
    Electronic Resource
    The tripartite structure of the undercoat in initial segments of Purkinje cell axons (1972)
    Springer
    Anatomy and embryology 139 (1972), S. 1-10 
    Details
    ISSN: 1432-0568
    Keywords: Plasmalemma ; Cerebellar Cortex ; Microtubules ; Synapses ; Myelin Sheath
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The undercoat of the initial axonal segment can be resolved into a three-layered structure. Directly beneath the axolemma lies the layer of granules. Each granule is 75 Å in diameter. The granules are arranged in rows that are separated from one another by clear spaces of 75 Å in the long axis of the axon and by about 95 Å in the transverse plane. Deep to this is a dense lamina about 75 Å thick. The third component may be a ridge made up of a web of 50 Å filaments forming a continuous spiral winding beneath the dense lamina.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00520942
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  • 5
    Electronic Resource
    Electronic Resource
    A brief note on the chemical nature of the precipitate within nerve fibers after the rapid Golgi reaction: Selected area diffraction in high voltage electron microscopy (1973)
    Springer
    Anatomy and embryology 139 (1973), S. 115-117 
    Details
    ISSN: 1432-0568
    Keywords: Cerebellar cortex ; Neurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The use of selected area electron diffraction in the high voltage electron microscope permits the identification of the crystalline rapid Golgi precipitate within single nerve fibers in nervous tissue. Spot diffraction patterns and ring patterns show the impregnation to be silver chromate,Ag2CrO4. This is confirmed by cobalt Debye-Scherrer X-ray diffraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00523632
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  • 6
    Electronic Resource
    Electronic Resource
    A light microscope study of the cytology and organization of neurons in the simple mammalian nucleus lateralis: Columns and swirls (1973)
    Springer
    Anatomy and embryology 141 (1973), S. 125-150 
    Details
    ISSN: 1432-0568
    Keywords: Rat ; Columns ; Swirls ; Interneurons ; Projection neurons ; Subdivisions ; Morphology ; Golgi ; Nissl ; Axons ; Dendrites ; Cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The lateral nucleus in the rat is investigated with several variants of the rapid Golgi method and in Nissl preparations. The neurons are divided into two classes according to their size and the disposition of their axons. The smaller neurons or interneurons have cross sectional areas less than 180 μm2, and short axons that ramify in the vicinity of the cell bodies. Small neurons have also been seen on rare occasions with longer axons that may leave the nucleus. The larger cells (areas greater than 180 μm2) have long axons that leave the nucleus and emit short, beaded, recurrent collaterals. In the rostral and caudal poles of the lateral nucleus, the large projection neurons as well as the small neurons are multipolar with swirled dendritic arborizations. Neurons in the dorsal rim and ventral third of the nucleus have similar dispositions of their dendrites. In the central columnar zone, the projection neurons have dendrites that are arranged in columns directed diagonally across the body of the nucleus in the 4 to 10 o'clock direction in the right lateral nucleus and the 8 to 2 o'clock direction in the left nucleus. A collection of small neurons is generally found in the medial hilus zone. In each part of the lateral nucleus, the neurons are arranged in characteristic ways.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519881
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  • 7
    Electronic Resource
    Electronic Resource
    Cytology and organization in the nucleus lateralis of the cerebellum: The projections of neurons and their processes into afferent axon bundles (1973)
    Springer
    Anatomy and embryology 141 (1973), S. 151-159 
    Details
    ISSN: 1432-0568
    Keywords: Synapses ; Development ; Migration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Projections and trabeculae consisting of neurons, neuroglial cells, and their processes extend from the rostral aspect of the nucleus lateralis of the rat. The dendrites of these neurons interweave with large packets of incoming myelinated fibers. Electron microscopy shows that synapses occur between these neurons and the afferent axons. Two possible developmental explanations for this arrangement are considered. (1) The cells may have been induced to migrate away from the main mass of the nucleus as a result of the delayed arrival of an important contingent of afferents. Alternatively, (2) these rostral cells may have migrated a longer distance for intrinsic reasons and consequently met their afferents at a location more peripheral to the main nuclear mass. In either case, the projections and trabeculae may reflect the segregation from the main nuclear mass of a certain group of neurons and their afferents having specific topographic or functional attributes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519882
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  • 8
    Electronic Resource
    Electronic Resource
    Axon terminals of the intrinsic neurons in the nucleus lateralis of the cerebellum an electron microscope study (1973)
    Springer
    Anatomy and embryology 142 (1973), S. 187-206 
    Details
    ISSN: 1432-0568
    Keywords: Neuron ; Synapses ; Interneuron ; Inhibition ; Excitation ; Cerebellar nuclei
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The large projection neurons of the lateral nucleus have long axons, which leave the cell mass in the superior cerebellar peduncle. These axons emit myelinated recurrent collaterals which have synaptic varicosities en passant. The varicosities are 2–5 μm in diameter and contain round, agranular synaptic vesicles ranging between 280 and 480 Å with diameters of approximately 400 Å. The vesicles lie in a moderately dark axoplasmic matrix with a mean packing density of 281/μm2. The varicosities synapse through Gray's type 1 junctions with dendrites and thorns of large and small neurons. They constitute 22% of the total axonal population on dendrites of large neurons and 10% on dendrites of small neurons. The recurrent collateral system may provide a means for positive feedback to the same neuron and other neurons of the neuropil. The small neuron or interneuron has a short axonal plexus. The axon is myelinated, and is distinctive with a light axoplasmic matrix and varicosities containing elliptical synaptic vesicles. The vesicles are loosely dispersed with a mean population density of 44/μm2. These varicosities synapse through an intermediate type of junction upon the somata of certain large and small neurons and they consitute 14% and 22% of the axosomatic synapses respectively. They also make synapses on dendrites, constituting 12% and 25% of the total population of axons synapsing with dendrites of large neurons and those of small neurons respectively. It is suggested that these are the inhibitory interneurons of the lateral nucleus. The corticonuclear input through Purkinje axons is the dominant influence on the lateral nucleus neurons. This inhibitory input is considerably larger on the large neurons than on the small ones. It is speculated that the axosomatic synapses are inhibitory. Excitatory influences, through the collaterals of mossy and climbing fibers and the recurrent collaterals of the large intrinsic neurons, impinge upon the dendrites, where the axons of both Purkinje cells and interneurons also terminate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519721
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  • 9
    Electronic Resource
    Electronic Resource
    On certain fluorescent axon terminals containing granular synaptic vesicles in the cerebellar nucleus lateralis (1973)
    Springer
    Anatomy and embryology 142 (1973), S. 239-258 
    Details
    ISSN: 1432-0568
    Keywords: Catecholamine ; Norepinephrine ; 5-hydroxytryptamine ; Dense-cored vesicles ; Neurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Thin, unmyelinated, green fluorescent fibers bearing fine beads or varicosities have been found in the neuropil and near blood vessels of the nucleus lateralis. In electron micrographs these fibers are identifiable as a class of axons, the CAT fibers, which contain large and small granular synaptic vesicles and agranular vesicles in their varicosities. There are two types of CAT fiber. 1) The CAT1 terminals contain many large and elongated vesicles, 700–1700 Å in size, with dark, homogeneously dense centers; a few small granular vesicles each with an intensely osmiophilic particle, and small agranular vesicles. These terminals have not been seen in synaptic contact with other elements of the neuropil. 2) The CAT2 terminals have a very thin unmyelinated connecting thread between small varicosities. The varicosities contain small agranular synaptic vesicles and small granular ones containing either a single dense particle, or an elliptical, intensely osmiophilic droplet flanked by lighter semicircular particles. Large granular vesicles, 750–950 Å each, with a variably dense center, are also found. These terminals form conventional axodendritic synapses with Gray's type 1 synaptic junctions and the subsynaptic specialization of Taxi, as well as synapses on thorns of spiny neurons. It is suggested that the CAT1 and CAT2 fibers may be the electron microscope equivalents of norepinephrine- and 5-hydroxytryptamine-containing fluorescent axons. These fibers probably have extrinsic origins since no fluorescent cells or perikarya with small or large granular vesicles have been found in the lateral nucleus. Their origins, however, are unknown. The proximity of these fluorescent fibers to blood vessels is discussed, and their functions are the subject of some speculation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519131
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  • 10
    Electronic Resource
    Electronic Resource
    Immunohistochemical localization of serotonin nerve terminals in the lateral entorhinal cortex of the rat: Demonstration of two separate patterns of innervation from the midbrain raphe (1980)
    Springer
    Anatomy and embryology 160 (1980), S. 121-129 
    Details
    ISSN: 1432-0568
    Keywords: Serotonin ; Entorhinal cortex ; Hippocampus ; Immunofluorescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of serotonin (5-hydroxytryptamine, 5HT) containing nerve terminals in the lateral entorhinal cortex (LEC) has been studied using antibodies against 5-HT in combination with fluorescence histochemistry. Thin, varicose, branching fibers were found to be distributed in a relatively even, diffuse pattern throughout all layers of the LEC. The largest amount of this type of 5HT innervation was in Layer I. This diffuse pattern of 5-HT terminals was supplemented by a dense network of 5HT terminals restricted to Layer III of a small (∼1 mm) strip of the LEC. The fibers in this layer were thicker and more convoluted and contained larger varicosities than fibers in any other layer. The existence of a distinct innervation by 5-HT terminals of only a small portion of the LEC demonstrates a hitherto unrecognized and important principle of heterogeneity in 5-HT innervation of cortex. It suggests that 5-5HT neurons in the raphe can selectively influence specific, narrow regions of the lateral perforant path system, which, in turn, affect the intrinsic hippocampal circuits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00301855
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