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  • 1
    Electronic Resource
    Electronic Resource
    On the development of non-pyramidal neurons and axons outside the cortical plate: The early marginal zone as a pallial anlage (1977)
    Springer
    Anatomy and embryology 151 (1977), S. 285-307 
    Details
    ISSN: 1432-0568
    Keywords: Development ; Cerebral Cortex ; Neurons ; Axons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The development of non-pyramidal neurons was studied in the pallium of albino rats using autoradiography after thymidine labelling (determination of “birth dates”), Golgi impregnations (differentiation of dendrites and axons) and electron microscopy including 3D-reconstructions (cytoplasmic differentiation and early synaptogenesis). The marginal zone appears between E13 and E14 and contains glial cells, axons and preneurons from the beginning. The latter can be identified by structural criteria (contacts, cytoplasm, nuclei). The first vertically oriented pyramidal neurons (cortical plate) appear within the marginal zone not before E16, separating its contents into a superficial (lamina I) and a deep portion (intermediate and subventricular zone). Since this old neuronal population of lamina I and the subcortical pallial region can be followed until adulthood, it is proposed to call the early marginal zone a “pallial anlage”. It can be demonstrated that during the whole period of neuron production (until E21) non-pyramidal neurons are added to all parts of the “pallial anlage”. The structural differentiation of non-plate neurons is described. Neurons form specific, desmosome-like contacts with axonal growth cones already on E14. Typical synapses (vesicle aggregations) have been observed two days later. In lamina I two types of neurons develop: horizontal neurons (Cajal-Retzius cells) and multipolar neurons (small spiny stellate cells). Subcortical pallial neurons retain mostly their clear horizontal orientation. Only neurons situated very close to the lower border of the cortex show dendritic branches extending into lamina VI. Axons appearing early in the neocortex originate not only from subcortical regions, but also from neurons of the paleopallium, the archicortex, the limbic cortex and the neighbouring neocortex. The tangential growth of the neocortex, as estimated from E14 onwards causes a strong dilution of the elements of the “pallial anlage” until adulthood. The classification of neurons outside the cortical plate and the fate of the total “pallial anlage” are discussed. As a consequence of these observations some modifications of the terminology of the Boulder Committee are proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318931
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  • 2
    Electronic Resource
    Electronic Resource
    Distribution patterns and individual variations of callosal connections in the albino rat (1982)
    Springer
    Anatomy and embryology 165 (1982), S. 213-232 
    Details
    ISSN: 1432-0568
    Keywords: Callosal connections ; Neocortex ; Columnar organization ; Rat ; Degeneration techniques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After complete callosotomy the distribution of degeneration products was re-investigated in adult albino rats. Three to seven days post operation, coronal, horizontal and “flattened” sections were impregnated according to the new methods of Gallyas et al. (1980) which stain degenerating axons and terminals, respectively. The regional distribution patterns of callosal terminals were directly visualized with dark field illumination at low magnification. With this technique the distribution pattern of axons and terminals could be compared between different cortical regions and individuals. Callosal terminals tend to accumulate in patches or bands along the borders of cortical regions and areas. The concentration of callosal terminals was especially high at the common corners of more than two cortical areas. The callosal system shows a rather constant distribution pattern which is composed of column shaped subunits. Considerable individual variations were recognized concerning the number, position, shape, density and contiguity of the columnar units either occupied by callosal connections or empty. Although the laminar distribution of callosal terminals shows some similarities in different areas of the cortex, there is no common laminar pattern characteristic either for the whole neocortex or for any cortical region. The comparison between consecutive sections stained either for degenerating fibers or degenerating axon terminals revealed that the callosal axons do not determine directly the arrangement and packing density of callosal synapses. Whatever determines the position and amount of callosal synapses this influence seems to be exerted via translation into the columnar organization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305478
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  • 3
    Electronic Resource
    Electronic Resource
    Über die akuten Veränderungen im Parietalcortex der Ratte nach spitzem Trauma (1971)
    Springer
    Acta neuropathologica 19 (1971), S. 249-264 
    Details
    ISSN: 1432-0533
    Keywords: Brain Edema ; Stab Wound ; Neocortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The parietal cortex of rats was examined by light and electron microscopy 1–120 min after a standardized stab wound (250×450×1800μm, constant stab velocity). The changes in the tissue are already visible qualitatively after 1 min. After about 4 min the expansion of tissue changes stops. 4 zones may be separated. Surrounding the stab canal concentrically they are relatively sharply defined. Zone I. Stab canal, haemorrhagical or “debris zone”, primary traumatic destroyed zone. The tissue units are here completely destroyed. Zone II. “Squashed” or “indirectly but irreversibly damaged” zone. It is ca. 80μm wide and contains apart from a protein-rich extracellular fluid almost exclusively swollen cells and cell fragments. Zone III. Swelling brain or “intracellular peritraumatic edema”. It is ca. 150μm wide and contains mainly dark neurones and swollen astroglia. Zone IV. Transitional zone of variable width. Here only the perivascular and perineural processes are swollen without changed neurone structure. In all swollen astrocytes mitochondria are altered typically (denser matrix, dilated cristae). Discussed are: The short latency period, Zone IV, causes of astroglial swelling, origin of extracellular fluid as well as mechanisms which limit the spread of extracellular fluid into Zone II.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00684602
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  • 4
    Electronic Resource
    Electronic Resource
    Cerebrovascular ultrastructural alterations after intra-arterial infusions of ouabain, scilla-glycosides, heparin and histamine (1975)
    Springer
    Acta neuropathologica 31 (1975), S. 45-58 
    Details
    ISSN: 1432-0533
    Keywords: Ouabain ; Scilla-Glycosides ; Brain Capillaries ; Blood-Brain Barrier ; Cerebral Blood Flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cardiac glycosides which inhibit Na/K-ATPase (ouabain, scilliroside, scillirosidin) as well as heparin and histamine were infused into a cannulated branch of the middle cerebral artery or by isolated head perfusion in cats and dogs. Ouabain permeating the blood-brain barrier (BBB) caused the same selective swelling of astrocytes and of certain presynaptic elements as after direct application to the brain tissue. The other cellular elements of brain tissue and the vascular endothelium did not react, although the latter was exposed to the highest drug concentrations (about 10−3 M ouabain). By the swelling about one third of the capillaries became more or less constricted accompanied by an increase in endothelial vesiculation and in the number of osmiophilic inclusions in all cells of the vascular wall and of the pericapillary tissue. Osmiophilic material resembling plasma proteins occurred in widened intercellular clefts indicating an increased BBB permeability after survival times (40 min). In contrast to the capillaries some terminal vessels are dilated which may correspond to shunt vessels causing an inhomogeneous, even increased cerebral blood flow after ouabain. Scilliroside and scillirosidin cause essentially the same changes as ouabain, but of smaller intensity and extent. In the present study, neither histamine nor heparin caused any structural change of the vessels or brain tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00696886
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  • 5
    Electronic Resource
    Electronic Resource
    Angioarchitectonics of rat cerebellar cortex during pre- and postnatal development (1980)
    Springer
    Acta neuropathologica 50 (1980), S. 131-138 
    Details
    ISSN: 1432-0533
    Keywords: Rat ; Cerebellum ; Vessels ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The adult arrangement and the development of stem vessels and capillaries was studied in the rat cerebellum. In principle, stem vessels branch and terminate at three levels: (1) the molecular layer, (2) the Purkinje cell-granular layer, and (3) the cerebellar white matter. All stem vessels are interconnected by the capillary network which is most dense in the Purkinje cell—granular layer. As in the neocortex, the stem vessels of the cerebellum are formed successively during development, so that the later they are formed the more superficial are their terminations. The formation of multiple stem vessels in the depths of fissures and sulci during both pre- and postnatal development may correlate to regional variations in, e.g., mitotic frequency or thickness of the external granular layer. The earliest “endo-parenchymal” branches are formed before the first neurons are present. Capillary growth by sprouting during the postnatal period parallels known regional differences in the timing of the neuronal maturation, e.g., increased synaptic density and oxidative metabolism. The findings in this investigation confirm and extend the results of an earlier morphometric study on capillary development in the cerebellar cortex. Although the angiogenetic factors remain unknown, the hypothesis of a link between the vascularization and the functional maturation of the brain is corroborated by the results. Knowledge of the normal vascular development seems necessary for an understanding of brain morphogenesis and for interpretation of primary pathogenetic mechanisms in various intoxications etc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00692863
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  • 6
    Electronic Resource
    Electronic Resource
    Postnatal vascular growth in the neocortex of normal and protein-deprived rats (1979)
    Springer
    Acta neuropathologica 47 (1979), S. 123-130 
    Details
    ISSN: 1432-0533
    Keywords: Rat ; Protein deprivation ; Neocortex ; Vessels ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The postnatal vascular growth in the neocortical area 18 of normal and pre- and postnatally protein-deprived rats was examined. For control rats the specific length, the specific surface and the volume fraction of vessels increased rapidly between 7 and 20 days of age. Thereafter, only a minor increase was seen. In protein-deprived rats there was no increase in the specific length of vessels between 7 and 10 days of age and this variable was still reduced at 30 days of age compared to controls. This reduction was due to a decrease in the specific length of thin vessels (Ø〈8.25 μ) whereas the specific length of wider vessels was not affected by the protein deprivation. There were no significant differences in the specific surface or volume fraction of vessels between control and protein-deprived rats. These findings indicate an adaptive increase in luminal diameter of vessels in the protein deprived rats during postnatal development. At 90 days of age no significant differences between vascular variables of control and protein-deprived rats were seen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00717035
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  • 7
    Electronic Resource
    Electronic Resource
    Postnatal vascular growth in the cerebellar cortex of normal and protein-deprived rats (1979)
    Springer
    Acta neuropathologica 47 (1979), S. 131-137 
    Details
    ISSN: 1432-0533
    Keywords: Rat ; Cerebellar cortex ; Protein deprivation ; Vessels ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The postnatal vascular growth in the cortex of vermis cerebelli folium IX of normal and pre- and postnatally protein-deprived rats was examined. The rate of increase in specific length of vessels seem to parallel the functional maturation of neurons in all cortical layers. From the first postnatal week there is a higher specific length of vessels in the Purkinje cell layer than in the adjoining parts of the molecular and granular layers. The results indicate that such differences are present also after the period of rapid vascular growth. Protein deprivation appears to affect the postnatal increase in specific length of vessels less in the Purkinje cell layer than in the granular and molecular layer where a significant reduction compared to controls was seen for the interval 7–20 days of age. At 90 days of age no significant differences were seen between control and protein-deprived rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00717036
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  • 8
    Electronic Resource
    Electronic Resource
    Golgi-like demonstration of “dark” neurons with an argyrophil III method for experimental neuropathology (1990)
    Springer
    Acta neuropathologica 79 (1990), S. 620-628 
    Details
    ISSN: 1432-0533
    Keywords: “Dark” neurons ; Silver staining ; Golgi-like demonstration ; In vivo induction ; Experimental neuropathology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A silver method is proposed for the selective, well-contrasted and reproducible demonstration of “dark” neurons in frozen, vibratome and paraffin sections cut at a thickness of 5 to 200 μm from aldehyde-fixed brains. The Golgi-like staining of the dendrites enables asorting of “dark” neurons according to characteristic neuron classifications. The staining procedure includes an esterification with 1-propanol, a treatment with diluted acetic acid and development. The esterification strongly increases the argyrophilia of both “dark” neurons and mitochondria. Unwanted co-staining of mitochondria is suppressed by the acetic acid treatment, while a special developer is used to render the staining controllable. The applicability of the method to experimental neuropathology is demonstrated by Golgi-like staining of “dark” neurons in rat brains exposed, before transcardial perfusion-fixation and delayed autopsy, to various pathological conditions including ischemia, hypoglycemia, trauma, status epilepticus, deafferentation and poisoning with kainic acid, colchicine and sodium azide, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294239
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  • 9
    Electronic Resource
    Electronic Resource
    Anti-noradrenergic drugs do not interfere with the development of callosal connections in the rat (1982)
    Springer
    Cellular and molecular life sciences 38 (1982), S. 1218-1219 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When noradrenergic transmission was suppressed by 6-OHDA, propranolol or phentolamine callosal fibers developed the same innervation pattern as in normal rats and the density of callosal connections did not increase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01959749
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  • 10
    Electronic Resource
    Electronic Resource
    Self-stabilization of neuronal networks (1986)
    Springer
    Biological cybernetics 54 (1986), S. 211-222 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract Between the extreme views concerning ontogenesis (genetic vs. environmental determination), we use a moderate approach: a somehow pre-established neuronal model network reacts to activity deviations (reflecting input to be compensated), and stabilizes itself during a complex feed-back process. Morphogenesis is based on an algorithm formalizing the compensation theory of synaptogenesis (Wolff and Wagner 1983). This algorithm is applied to randomly connected McCulloch-Pitts networks that are able to maintain oscillations of their activity patterns over time. The algorithm can lead to networks which are morphogenetically stable but preserve self-maintained oscillations in activity. This is in contrast to most of the current models of synaptogenesis and synaptic modification based on Hebbian rules of plasticity. Hebbian networks are morphogenetically unstable without additional assumptions. The effects of compensation on structural and functional properties of the networks are described. It is concluded that the compensation theory of synaptogenesis can account for the development of morphogenetically stable neuronal networks out of randomly connected networks via selective stabilization and elimination of synapses. The logic of the compensation algorithm is based on experimental results. The present paper shows that the compensation theory can not only predict the behavior of synaptic populations (Wagner and Wolff, in preparation), but it can also describe the behavior of neurons interconnected in a network, with the resulting additional system properties. The neuronal interactions-leading to equilibrium in certain cases-are a self-organizing process in the sense that all decisions are performed on the individual cell level without knowing the overall network situation or goal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318417
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