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E Winkelmann

Publications and source records attributed to E Winkelmann.

At least 55 records · Page 3Linked to original sources
PubMed1985

Golgi and Nissl studies of the visual cortex of the bottlenose dolphin.

Nissl, Golgi and fibre preparations were made of the cerebral cortex of the lateral gyrus of the bottlenose dolphin (Tursiops truncatus) in the region where visual evoked potentials have been reported (Sokolov et al., '72; Ladygina et al., '78). In the adult the visual cortex is relatively thin (average about 1,300 micron) for so large a brain (fixed brain weight for a typical adult in our series was 1,330 g). Layers I, III, and VI are wide and represent three-quarters of the total cortical thickness. Layer I contains few cell bodies, while III and VI have a variety of pyramidal and nonpyramidal neurons. Layers II and V are narrow and contain striking palisades of darkly staining pyramidal cells that are particularly large in layer V. No clearly demarcated layer IV is present in the adult dolphin visual cortex. Many of the neurons identified with the Golgi technique are typical of pyramids in other mammals, with a single apical dendrite and a bouquet of basal dendrites, mostly highly spiny. Others are unusual in having bifurcated or oblique apical dendrites. Typical large and small spiny and nonspiny stellates are also found, mainly in layers III and VI. In addition various forms of spindle-shaped, bipolar and multipolar neurons are found in most layers. An 18-day-old brain shows signs of immaturity in its visual cortex. It is thinner (970 micron) and on average its neurons are smaller, paler, and more densely packed. Especially the pyramids of layer V are much smaller than in the adult. Also, a distinct "granular" band occurs between layers III and V and seems to be a rudimentary layer IV. At 3 years of age most of the adult features have developed, but layer IV is still detectable. No striking differences were observed in cell and fibre architecture between the cortex of the lateral gyrus and that of the so-called "calcarine" area that has also been considered as "visual." We concluded that, although different in many respects from other mammalian visual cortices, that of the dolphin is apparently well developed and differentiated.

Aging↗
PubMed1985

Ultrastructural development of the dorsal lateral geniculate nucleus of genetically microphthalmic mice.

The ultrastructure of the dorsal lateral geniculate nucleus (dLGN) of microphthalmic mice is described in affected white homozygotes (mi/mi) and their apparently normal grey littermates. In the dLGN of mi/mi animals populations of apparently normal axon terminals were observed, including some with flattened synaptic vesicles and other small terminals with round vesicles and dark mitochondria (RSD), possibly of cortico-thalamic origin, just as in normal mice. However, no typical large retinal endings with round vesicles and pale mitochondria (RLP) are visible. Instead they appear to be replaced by other large boutons with round vesicles and dark mitochondria (RLD). Eye enucleation does not cause degeneration of these RLD terminals. In apparently normal grey littermates RLP terminals are present and they degenerate when an eye is enucleated. But RLD endings are also found in these animals, and never degenerate after enucleation. The origin of the RLD terminals is unclear but seems not to be cortical. These findings are compared with those of Cullen and Kaiserman-Abramof (1976) in a different strain (ZRDCT-An) of anophthalmic mouse in which they found large replacement terminals similar to our RLD boutons.

Animals↗
PubMed1985

On the ontogenetic development of the rat dorsal lateral geniculate nucleus. I. GCR-neurons at postnatal day 7--a Golgi-electron microscopic study.

The morphology and synaptic input of four geniculo-cortical relay neurons of albino rats of postnatal day (PD) 7 has been studied with light and electron microscopy, utilizing the combined Golgi-EM technique. Although the nerve cells investigated did show a characteristic relay-cell appearance of the adult, certain dendritic structures exhibited immature character. These were the dendritic swellings, or "growth buds" occurring throughout the whole length of the dendrites, but particularly along the segments and at bifurcations of thin distal dendritic portions. These dendritic thickenings together with the transient spine-like hairy processes were seen to receive many synaptic endings of various developmental stages. The majority of synaptic junctions both on the dendritic swellings and on dendritic shafts were of the asymmetric type. Contrary to our expectation, no proximo-distal gradient could be demonstrated in the maturation of axodendritic synapses, at least not during the first synaptogenetic period, i.e., at PD 7. Also, all axosomatic synapses in the PD7 rat LGNd were asymmetric, indicating that the replacement of asymmetric synapses by symmetric ones (characteristic for the adult stage) occurs only after the first synaptogenetic period. The rarity of Gray II type, symmetric contacts during the early synaptogenesis (i.e., at PD 7) explains the absence of triadic, or serial synapses which will develop only later, during the second synaptogenetic period.

Animals↗
PubMed1985

[Types of neurons in the visual cortex of the rat, identified in Nissl- and deimpregnated Golgi preparations].

Neuronal types of the rat's visual cortex were identified in Nissl stained and deimpregnated Golgi sections (rapid Golgi method modified by Fairén et al. 1977, Golgi-Bubenaite, Golgi-Kopsch and modified by Braitenberg; deimpregnation after FAIREN et al. 1977 and Braak and Braak 1982, respectively). Cytoplasm and nucleus become visible in deimpregnated neurons and can then be counter-stained with methylene blue or toluidin blue. Somal and nuclear features of Nissl stained and deimpregnated neurons were compared. Provided that these features as well as the specific localization, the relative size and the shape of the soma agree the neurons are identical. We could find that the following neuronal types are identical in Golgi and Nissl stained sections: pyramidal cells of layers II-VI, pyramid-like neurons of layers VI and VII (VIa, b, c) (type C, Werner et al. 1982), multiangular neurons of layer I (type A, Werner et al. 1982), spiny stellate cells of layer IV, sparsely spined neurons with ascending axons (Martinotti cells) (type H, Werner et al. 1982), large and medium-sized spine-free, multipolar neurons (basket cells) (type B, Werner et al. 1982). Bipolar neurons and chandelier cells are identical with neurons poor in cytoplasm (types E, F, G, Werner et al. 1982). Until today two neuronal types could not be identified: type D of L I (Werner et al. 1982) and small, sparsely-spined neurons of layer IV with variable axons (Hedlich and Winkelmann 1982; Hedlich et al. 1984). Characteristics of somata, dendrites and axons of neurons identified in this paper are summarized in table 1. In most cases, these findings confirm earlier suppositions concerning the identity of neuronal types of the rat's visual cortex in Golgi and Nissl stained sections (Werner et al. 1979) and verify the values of their frequency and distribution pattern (Werner et al. 1982).

Animals↗
PubMed1984

[Sparsely-spined neurons in the rat visual cortex].

Sparsely spined neurons were described in the visual cortex of the rat. A large cell type was found in all laminae, but mainly in L III-L V. The soma is large and the dendrites are vertically oriented. In most cases, the axon originates from the upper main dendrite or the upper soma pole. The axonal arborization is vertical. In the terminal axonal segments the number of boutons is high. A small neuron type could be demonstrated in L IV. The soma is small, and the dendritic field is nearly multipolarly or horizontally oriented. The axon derives from the basal pole or laterally at the soma.

Animals↗
PubMed1984

[Morphometric analysis of the dorsal lateral geniculate body of the laboratory mouse and microphthalmic variants].

The dorsal lateral geniculate nucleus (dLGN) of the mouse (strain 944 with microphthalmus syndrome, P. Hertwig 1942) has been morphometrically investigated. The eyes of the gray littermates develop normally (control animals) while the white littermates show the microphthalmus syndrome (microphthalmic animals). Four male twentyone day old animals were examined. Following perfusion with formaldehyde (diluted 1:4 with H2O) Nissl stained frontal sections were used for classification of neurons. we differentiate between projection neurons (PN) (geniculo-cortical relay neurons) and interneurons (IN). We succeeded in identifying these two cell types using deimpregnated Golgi preparations (Fairén et al. 1977), which were counterstained with methylene blue (0.1%). The neuronal packing density and the ratio PN:IN were conventionally determined using 20 micron thick sections from both control and microphthalmic animals. In both cases this ratio was 12:1 (= 8% IN). Measuring fields distributed in a meander-like manner were selected for estimating the neuronal density. Measuring fields giving equal values were connected. The results show that we can distinguish between 3 regions of dLGN: lateral, medial and caudal. They differ with regard to neuronal packing density, size and structure of the PN. Using 3 micron thick Nissl stained sections from both control and microphthalmic animals the size and structure of PN were automatically determined using the picture processing device "MORPHOQUANT" VEB Carl Zeiss JENA). The distribution pattern of IN is apparently uniform. The microphthalmus syndrome produces a diminished number of pathologically changed retinal fibers. The morphometrically registered findings show that within the dLGN, of the microphthalmus mouse the neuronal packing density increased (diminution of neuropil), the size of PN decreased and their structural density increased (transneuronal dystrophy). Compared with the other parts, the medial part of the dLGN is minimally altered.

Animals↗
PubMed1984

The ventral lateral geniculate nucleus of the albino rat morphological and histochemical observations.

The ventral lateral geniculate nucleus (vLGN) of albino rats (Wistar strain) has been described histologically and histochemically. Special attention was paid to the identification of cell classes in Nissl and Golgi preparations, the afferent and efferent connections of vLGN cells and the demonstration of enzymes of energy and transmitter metabolism. Topographical aspects were taken into consideration, too. The main results can be summarized as follows: In the rat vLGN, three subnuclei can be distinguished: the lateral and medial subnucleus and the intergeniculate leaflet. In the rostral vLGN, the lateral and medial subnucleus is separated by a vertical fibre bundle which contains retinal axons. Our own experiments and findings of other groups revealed that the rat vLGN is connected with numerous brain structures. There is no efferent projection to cortical regions. Afferent fibres reach the vLGN from retina, visual cortex, superior colliculus, pretectal region, zona incerta, contralateral vLGN, dorsal raphe nucleus, locus coeruleus, mesencephalic reticular formation, vestibular and dorsal tegmental nuclei. An efferent projection has been found to superior colliculus, pretectal region, dorsal lateral geniculate nucleus, contralateral vLGN, zona incerta, pontine nuclei, suprachiasmatic nucleus, lateral terminal nucleus of the accessory optic system and intralaminar nucleus of thalamus. Comparative findings suggest that the lateral subnucleus is involved in "specific projections", whereas the medial subnucleus projects to "unspecific zones". For detailed information see text. Five classes of neurons can be distinguished in Golgi and Nissl preparations. Class 1 cells are medium-sized to large with smooth thick proximal but branched spiny distal dendrites. They are confined to the lateral subnucleus and the intergeniculate leaflet. In the lateral subnucleus, class 1 cells could be identified as geniculo-tectal relay neurons (Brauer and Schober, 1982). All other classes of neurons are spineless or sparsely spined. Class 2 cells (giant neurons) of unknown function could be found in the lateral and medial subnucleus. Class 3 cells (medium-sized multipolar neurons) can mainly be found in the medial subnucleus. They are good candidates for neurons projecting to the contralateral vLGN. Class 4 cells (bipolar neurons) occupy the ventromedial part of the medial subnucleus and are very similar to cells localized in the adjacent zona incerta. Cells belonging to this type could found to be labelled by the HRP reaction product after injection of this enzyme in the pontine region.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylcholinesterase↗
PubMed1983

[Degenerative changes in the occipital neocortex in chronically amphetamine treated rats].

Neurons of the Wistar-rats' occipital cortex were morphologically investigated after chronical application of amphetamine. The nerve cells impregnated according to the Golgi-Kopsch technique showed in part changes on both the dendrites and in the axonal region. Besides a partial reduction of spines and of peripheral dendritic arborizations round varicosities of different density could be observed on the dendrites and on the axon, either, which were discussed to be due to a neurotoxic effect of amphetamine.

Amphetamine↗
PubMed1982

A comparative light microscopic investigation on geniculo-cortical relay neurons in rat, tree shrew and cat.

The morphology of geniculo-cortical relay neurons (GCR-neurons) of tree shrew, rat and cat differs intraspecifically and interspecifically from each other. Intraspecific differences in the cat have been explained functionally by the W-, X-, and Y-characteristics of cells (Wilson et al. 1976). Analogous morpho-functional correlations may also explain the morphological differences in tree shrew and rat. The interspecific differences in the morphology of GCR-neurons seem to be closely correlated to the levels of visual specialization in the three species in which the rat represents a basal developmental stage.

Animals↗
PubMed1982

[Comparative volumetric studies of the lateral geniculate body of mammals].

Volumetric investigations of the dorsal and ventral nucleus of the lateral geniculate body (dLGN and vLGN) in 16 mammalian species showed that forms with a high level of neocorticalization are characterized by a high quotient of dLGN and vLGN volumina. This result may be explained by the very different fibre connections of these two nuclei and the close relationship of the dLGN to the visual cortex. Compared with terrestric forms of the same body size tree living forms belonging to the same mammalian order have a larger LGN. The dLGN of these arboreal species exhibits additionally a higher level of histological differentiation (lamination). So we can conclude that there is a correlation between LGN volumina and the occurrence of dLGN lamination in members of the same order. This rule cannot be applied generally to species belonging to different orders.

Animals↗
PubMed1982

Topographical distribution of neuronal types in the albino rat's area 17. A qualitative and quantitative Nissl study.

1. Using Nissl preparations of adult male albino rats the topographical distributions of 10 neuronal types of the area 17 were ascertained in medio-lateral and dorso-ventral direction. 2. Two groups of neuronal types and one intermediate type are distinguished: (i) neurons rich in cytoplasm: pyramidal cells in L II-VI, stellate cells in L IV, one type each in L I and L VII, and a particularly large neuronal type in L II-VI; (ii) neurons poor in cytoplasm: one type in L I, three types in L II-VII and (iii) the intermediate type in L II-VI. 3. In the area 17, 93% of neurons are rich in cytoplasm (except the particularly large neuronal type B, 3.5%) (category-I-neurons = projection neurons), 2.9% of neurons are poor in cytoplasm (category-II-neurons = interneurons), and 0.6% are of the intermediate type. The latter may correspond with the Martinotti cell. At present we can only speculate, which cell type in Golgi preparations corresponds with the type B. 4. Taking into account the shrinkage of histologically treated tissue the number of neurons within a fresh volume of area 17 can be estimated. There are about 40,000 neurons within a volume of 1,000 microns x 1,000 microns basis. 5. Each layer is characterized by a specific amount of certain neuronal types, which are intermingled. 6. The distribution pattern of neuronal types change considerably in dorso-ventral direction. Medio-laterally there are only random deviations. 7. There are much more neurons poor in cytoplasm in superficial layers than in deeper layers. 8. In L I and L Va the highest and in L VII the smallest percentage of neurons poor in cytoplasm could be found. 9. L IV is characterized by its high number of stellate cells, the relatively high portion of the particularly large neuronal type B and small portions of pyramidal cells and neurons poor in cytoplasm. 10. As far as possible the functional aspects of the presented findings are discussed.

Animals↗
PubMed1982

[Types of neurons in the visual cortex of the adult and young rat].

The neurons of the visual cortex of adult und juvenile rats (Wistar) were studied with Golgi Rapid and Golgi Kopsch methods at the age of one to twenty days, 4 months and 18 months. The nerve cells were classified according to the form and size of their soma, the branching and surface of their dendrites and their axonal ramification. The neuron types show great similarities with those described in other species. We distinguish pyramidal neurons in L II-L VI, pyramid-like neurons--e.g. horizontally orientated neurons--neurons with a thick basal dendrite and multiangular neurons in L I as well as the spiny multipolar neurons in L IV all showing spiny dendrites and long axons. Neurons with spiny or sparsely spined dendrites and short axons are spine-free multipolar neurons with horizontal axons, sparsely spined polarized neurons with vertical axons, spine-free bipolar neurons with vertical axons and chandelier neurons. In general, all described cell types are nearly undifferentiated in the first postnatal week. The axons are in a more advanced stage than soma and dendrites at this time. During the process of differentiation the soma looses its irregular shape and the somaspines disappear. The immature dendrites show varicosities, which disappear during dendritic lengthening. The dendritic surface becomes either smooth or spiny. The axonal growth is connected with a loss of varicosities and finally with the formation of terminal boutons. At the time of eye-opening all described cell types have reached their differentiated state, but spine density and distal dendritic length have not yet achieved adult values.

Age Factors↗
PubMed1982

[Principles of synaptic organization in the central nervous system of vertebrates. Regional structural differences with special reference to the visual system].

The large variety of neuromorphological and neurophysiological data makes it necessary to look for possible principles of intrinsic organization and for common features and essential differences in the structure of neuronal networks in the CNS. Comparing the references on these networks one finds different termini technici related to interneuronal synapses such as "diads", "triads" complex synapses and glomeruli. AKERT and STEIGER (1967) discussed "glomeruli" in a considerable review. The ultrastructural analysis of the neuronal processes in these synaptic complexes has contributed considerably to our understanding of their synaptic connections. We differentiate "conventional" synapses such as simple axo-dendritic, axo-somatic, axo-spinous and axo-initialsegment synapses from the so-called "unconventional" synapses such as axo-axonic, dendro-dendritic (= serial) and reciprocal synapses. In the prepiriform, hippocampal, and visual cortices--even in the glomeruli of the turtle's cortex and in the glomeruli of the cerebellar cortex there are no serial but only simple synapses, whereas in the glomeruli of the olfactory bulb and in the glomeruli of the lateral geniculate body there are besides simple synapses--serial synapses with presynaptic dendrites. Similar complex synaptic arrangements are present in the pulvinar, colliculus superior, thalamus, globus pallidus and medulla, but not in the neostriatum. That means that the--many cortical neuronal types--are directly connected by simple synapses, but other--less numerous neuronal types--in the brain stem (with exception of the neostriatum) are coupled together in a very complex manner, where serial synapses, triads and reciprocal synapses (retina) play a very important role. The functional relevance of these synapses and the importance of an exact nomenclature for interdisciplinary cooperation are discussed.

Animals↗
PubMed1981

A loss of GABAergic hippocampus innervation in rats with cobalt-induced epilepsy demonstrated by Wolman's fluorescence method.

The topohistochemistry of gamma-aminobutyric acid (GABA) was studied in the hippocampus of rats with epileptiform activity provoked by cortical implantation of cobalt-agar pellets and in control rats with implanted agar-pellets. Using the GABA specific fluorochroming procedure of Wolman (1971) a distinct decrease of GABA fluorescence was found especially in the pyramidal and granular layer, but only in the animals with a typical epileptiform activity of the EEG. The results support the hypothesis that there is a lack of GABAergic inhibition in epileptic individuals, but the anticonvulsive effect of GABA depends on structural and functional relations in the specific type of seizure.

Animals↗
PubMed1981

[Morphology of the orbitofrontal cortex in persons schizophrenic psychotics. A Golgi and electron microscopy study].

By employing Golgi's method it is possible to demonstrate the whole neuron with all structural details in the brain of adults. In the orbitofrontal cortex of deceased persons with schizophrenic psychoses the following morphological findings can be obtained which are not demonstrable by other methods: 1. Mainly pyramidal cells with thick and partly sinuous main dendrites which suggest the presence of an increase in spines. 2. Irregularly arranged triangular cells in the lamina VI with thickened dendrites and increased density of spines. 3. Splitting of the myelin lamellae and deposits of various origins and structures. These findings can be interpreted as a possible expression of a changed function.

Adult↗