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Biomedical subjects

E Braak

Publications and source records attributed to E Braak.

At least 109 records · Page 6Linked to original sources
PubMed1986

Nuclear configuration and neuronal types of the nucleus niger in the brain of the human adult.

The pigmentoarchitectonic analysis of the human nucleus niger reveals three main territories: Pars compacta, pars diffusa and pars reticulata. Seven subnuclei are recognized within the pars compacta. The nerve cell types forming the nucleus niger were investigated using a Golgi de-impregnation technique in combination with counterstaining of intraneuronally deposited pigment granules. Three principal types of neurons were defined: Type I was a medium-sized to large neuron, mainly encountered in the pars compacta, giving off a few thick and sparsely branching dendrites. These cells were richly endowed with elongated patches of Nissl material that were mainly found in the peripheral portions of the dendrites. One pole of the cell body contained tightly packed neuromelanin granules. Type II neurons were mainly found in the pars reticulata. They were variable in size and shape and generated, similar to type I neurons, extended and sparsely branching dendrites. Type II neurons were devoid of neuromelanin. A considerable number of these cells were lacking in lipofuscin deposits as well. Type III neurons occurred in all portions of the nuclear complex. The small cell body gave rise to a few thin and spineless dendrites. The axon and filiform processes of the dendrites showed small varicosities irregularly spaced apart. The pale cytoplasm contained small and intensely stained lipofuscin granules, which did not tend to agglomerate. Intraneuronally deposited neuromelanin and lipofuscin pigment can be considered a natural marker of the neuronal type in the nucleus niger of the human adult. The technique and the data provide a basis for investigations of the aged and the diseased human brain.

Adult↗
PubMed1985

Somatostatin-like immunoreactivity in non-pyramidal neurons of the human isocortex.

The distribution of somatostatin-immunoreactive cell bodies and axons throughout the human isocortex and subjacent white matter was examined. Vibratome sections of cortical tissue (30-40 micrometers thick) obtained at surgery were treated to reveal the antigen by the unlabelled antibody enzyme method. Two types of somatostatin-immunoreactive axons were present: short, coiled axons and extended ones that follow a straight course in various directions. Somatostatin immunoreactive nerve cell bodies were encountered in layers II-VI and in the subjacent white matter. The majority of labelled cells were found in the white matter and layer VI, and then in layers II and III. The immunoreactive perikarya were fusiform, triangular or multipolar in shape and did not show preferential orientation of their long axis. Frequently, the fusiform neurons in layer VI and in the white matter were aligned parallel to radiate bundles of myelinated fibres. The immunoreactive neurons gave rise to a few thick dendrites. Often thin axon-like processes could also be recognized, originating either from the cell body or from a thicker dendrite. After destaining of the chromogen and counterstaining with aldehydefuchsin and gallocyanin chromealum, the formerly immunoreactive neurons displayed a light and eccentrically located nucleus. The soma contained only a sparse amount of basophilic substance and was nearly devoid of lipofuscin granules. In electron micrographs, the cisterns of the rough endoplasmic reticulum (RER) were localized near the periphery of the soma. Immunoreactivity occurred along membranes of the RER cistern, outer mitochondrial membrane, and in particles 120-150 micrometers in diameter. Rounded areas (up to a diameter of 1 micrometer) lacked immunoreactivity. Furthermore, there were a few tiny lysosomes.

Adult↗
PubMed1985

On areas of transition between entorhinal allocortex and temporal isocortex in the human brain. Normal morphology and lamina-specific pathology in Alzheimer's disease.

The allocortical entorhinal region does not gradually transform into the temporal isocortex. Instead, there is an extended stretch of "transentorhinal" cortex with interdigitation of allocortical and isocortical laminae. The main feature of this transition zone is that the superficial layer of large multipolar nerve cells (Pre-alpha) of the entorhinal region gradually sweeps downward and follows an oblique course through the outer layers. During this course the star-shaped nerve cells of Pre-alpha are transformed into pyramidal cells. The layer Pre-alpha projection cells are particularly prone to the development of neurofibrillary changes of the Alzheimer type. In cases of presenile and senile dementia almost all of the layer Pre-alpha projection neurons are changed pathologically. The isocortical pyramidal cells of layers II to IV are far less inclined to develop neurofibrillary changes. In the transentorhinal cortex, the tangle-bearing neurons follow an oblique course through the superficial laminae and are finally located between the isocortical layers III and IV, findings that confirm the assumption that these neurons are constituents of the allocortical layer Pre-alpha. Layer-specific pathology of the profound stratum as well confirms the transentorhinal region as being formed by interdigitating allocortical and isocortical layers.

Adult↗
PubMed1985

On layer III pyramidal cells in the parastriate borderzone of man.

The parastriate borderzone in the human occipital cortex is made conspicuous by clusters of large pyramidal cells in layer III (limen parastriatus gigantopyramidalis: von Economo and Koskinas 1925). Experiments in higher primates provide evidence that the vertical meridian is represented in this region and that these large pyramidal cells connect the parastriate borderzone of both hemispheres via callosal fibres. Golgi preparations of the human parastriate borderzone reveal that the large pyramidal cells generate a stout apical dendrite which gives rise to several side branches in layer III and terminal ramifications in layer II. An unusual feature is that the apical dendrite is almost devoid of spines and that its side branches are only sparsely spined as well. Both the basal and lateral portions of the cell body give rise to spiny dendrites having their domain within layers III and IV. In pigment-Nissl preparations, the large layer III pyramids are marked by coarse and distinct Nissl bodies and a bowel-shaped accumulation of faintly tinged lipofuscin granules located close to the nucleus. Electron micrographs show that up to 30% of the soma membrane are covered by large boutons which make multiple synaptic contacts. This contrasts to the appearance of most other types of cortical pyramydal cells which normally show only a few axo-somatic contacts.

Adult↗
PubMed1984

Neuronal types in the lateral geniculate nucleus of man. A Golgi-pigment study.

Nerve cell types of the lateral geniculate body of man were investigated with the use of a transparent Golgi technique that allows study of not only the cell processes but also the pigment deposits. Three types of neurons have been distinguished: Type-I neurons are medium- to large-sized multipolar nerve cells with radiating dendrites. Dendritic excrescences can often be encountered close to the main branching points. Type-I neurons comprise a variety of forms and have a wide range of dendritic features. Since all intermediate forms can be encountered as well, it appears inadequate to subdivide this neuronal type. One pole of the cell body contains numerous large vacuolated lipofuscin granules, which stain weakly with aldehyde fuchsin. Type-II and type-III neurons are small cells with few, sparsely branching and extended dendrites devoid of spines. In Golgi preparations they cannot be distinguished from each other. Pigment preparations reveal that the majority of these cells contains small and intensely stained lipofuscin granules within their cell bodies (type II), whereas a small number of them remains devoid of any pigment (type III). Intermediate forms do not occur.

Adult↗
PubMed1984

Neuronal types in the neocortex-dependent lateral territory of the human thalamus. A Golgi-pigment study.

Nerve cell types of the neocortex-dependent nuclei of the human thalamus were investigated with the use of a transparent Golgi technique, that allows one to study not only the peculiarities of the cell processes, but also the marking characteristics of the intraneuronal lipofuscin pigment deposits. Three principal types of neurons have been distinguished: Type I is a medium-sized to large neuron with a profusely radiating dendrite system. Numerous large vacuolated lipofuscin granules are contained in one pole of the cell body. Type II is a small to medium-sized neuron with a few sparsely branching dendrites. Small and intensely stained pigment granules are dispersed within the cell body. Type III is a medium-sized to large neuron with only a few thick and almost unbranched dendrites devoid of spiny appendages. The dendrites extend over long distances. The cell body is devoid of lipofuscin granules.

Aged↗
PubMed1984

Canine ceroid lipofuscinosis, a model for ageing of the human isocortex.

In canine ceroid lipofuscinosis (one case studied), isocortical layer IIIab pyramidal cells develop spindle-shaped enlargements of their proximal axon filled with lipopigment, a feature that can be observed in juvenile and adult type of human neuronal ceroid lipofuscinosis and in normal ageing of the human isocortex as well.

Aging↗
PubMed1983

On three types of large nerve cells in the granular layer of the human cerebellar cortex.

The large nerve cells of the granular layer of the human cerebellar cortex have been investigated by means of a newly developed Golgi technique that reveals the pigmentation pattern of individual nerve cells through transparent impregnations of their cell bodies and cellular processes. Three types of large nerve cells have been distinguished: Type I cells correspond to the Golgi cells. They have a rounded or polygonal cell body with only a few dendrites that radiate in all directions. The axon ramifies profusely, close to the parent soma. Cells of this type are most frequently encountered among the large cells of the granular layer. Type I cells contain only a few pigment granules. Type II cells have a fusiform or triangular cell body with a few rather extended dendrites that rarely ramify. Cells of this type are either devoid of pigment or contain a few large pigment granules that can be stained intensely by aldehydefuchsin. Type III cells are multipolar neurons with a fair number of dendrites originating from any point of the soma. The dendrites extend into the deep portions of the molecular layer. Here and also within the Purkinje cell layer they repeatedly branch off forming a dense dendritic arborization. Cells of this type are evenly distributed throughout the entire granular layer and throughout the adjacent portions of the Purkinje cell layer and the white matter as well. Type III cells are filled with tightly packed lipofuscin granules. The pattern of pigmentation is characteristic for each of these neuronal types. The three types of large nerve cells within the granular layer of the human cerebellar cortex can therefore be distinguished not only in Golgi impregnations but also in pigment-Nissl preparations.

Adult↗
PubMed1983

Neuronal types in the basolateral amygdaloid nuclei of man.

A parcellation of the human basolateral amygdala is given on the basis of pigmentoarchitectonic analysis. Examination of Golgi preparations and deimpregnated preparations counterstained for lipofuscin pigment revealed three classes of nerve cells: Class I neurons generate a stout main dendrite from one pole of the cell body and several minor ones from the base opposite to the main process. The dendrites are covered with spines. The axon follows a straight course and gives off numerous collaterals. Class I neurons in the lateral and accessory basal nucleus contain finely granulated and widely dispersed pigment. Cells located in the basal nucleus store a large amount of pigment, concentrated at one pole of the cell body. The small class I neurons in the granular nucleus and the intercalated cell masses are marked by large vacuolated pigment granules. Class II neurons have smoothly contoured or sparsely spined dendrites. Size and shape of their cell bodies vary. They contain a large amount of course and intensely stained lipofuscin granules. Class III neurons display similar features in the Golgi preparation but their cell bodies are devoid of pigment. A frequently occurring type is a tiny cell with thin dendrites and profusely branching local axon. Each of the different classes of neurons shows a characteristic pattern of pigmentation. Therefore, Nissl preparations combined with a pigment staining technique, offer the particular advantage of distinguishing the spine-laden neurons from sparsely spined or aspinous types.

Adult↗
PubMed1983

Isocortical pathology in type C Niemann-Pick disease. A combined Golgi-pigmentoarchitectonic study.

A case of Niemann-Pick disease was examined with Golgi preparations and a transparent Golgi impregnation counterstained for intraneuronal pigment deposits. There was a specific type of storage of unmetabolized substrate restricted to certain nerve cell types. The most conspicuous changes in the isocortex were: 1) dilated axonal segments in layer IIIab pyramidal cells filled with storage material; the volume of these axonal expansions often exceeded that of the soma; 2) distension of layer IIIc, layer V, and layer VIa pyramidal cell perikarya with storage material; 3) new formation, elongation, and vertical orientation of basal dendrites in layer V pyramidal cells; 4) well-preserved pyramidal cells almost devoid of storage material and generally small in size were frequently found in layers II and IV, and to a lesser extent in layers III, V, and VI; 5) severe numerical reduction of small pigment-laden stellate cells in layers II and III; and 6) reduction of stellate cells devoid of lipofuscin pigment. These cells only occasionally contained small amounts of storage material.

Adult↗
PubMed1983

Morphological studies of local circuit neurons in the cerebellar dentate nucleus of man.

Golgi preparations reveal the existence of two classes of nerve cells in the human dentate nucleus. Relatively large principal cells predominate. Small local circuit neurons are scattered throughout the nuclear gray. By means of a newly developed de-impregnation technique the pattern of pigmentation of both cell types can be studied. The principal cells show a considerable amount of finely granulated and faintly tinged pigment, whereas the local circuit neurons contain only a few large and intensely stained lipofuscin granules. The local circuit neurons give off a few smoothly contoured and rather extended dendrites. The axon is generated from either the cell body or a dendrite by way of a cone-shaped initial portion. A thin thread-like segment follows. Further distally, the caliber of the axon increases abruptly. This thick portion branches off several times at short intervals giving off fine processes with bead-like enlargements. Occasionally, a second axon is generated from these cells.

Cerebellum↗
PubMed1982

A simple procedure for electron microscopy of Golgi-impregnated nerve cells.

Most of the precipitations that normally fill up Golgi impregnated nerve cells can easily be removed by placing the material in a diluted solution of ammonia for several hours. A very fine scattering of electron-dense particles remains. Preparations processed in this way can be studied electron microscopically, in this way rendering fine structural examination of previously identified neurons possible. The method is applicable for silver chromate Golgi techniques and can be used for all parts of the brain.

Animals↗
PubMed1982

Neuronal types in the striatum of man.

Nerve cells of the human striatum were investigated with the use of a newly developed technique that reveals the pattern of pigmentation of individual nerve cells by means of transparent Golgi impregnations of their cell bodies and processes. Five types of neurons are distinguished: Type I is a medium-sized spine-laden neuron with an axon giving off a great number of collateral branches. The vast majority of the cells in the striatum belong to this type. Numerous intensely stained lipofuscin granules are contained in one pole of the cell body and may also extend into adjacent portions of a dendrite. Type II is a medium-sized to large neuron with long intertwining dendrites decorated with spines of uncommon shape. A distinguishing feature of this cell type is the presence of somal spines. This cell type is devoid of pigment or contains only a few tiny lipofuscin granules. Type III is a large multipolar neuron. The cell body generates a few rather extended dendrites that are very sparsely spined. The finely granulated pigment is evenly dispersed within a large portion of the cytoplasm. Type IV is a large aspiny neuron with rounded cell body and richly branching tortuous dendrites. The axon branches frequently in the vicinity of the parent soma. Large pigment granules are concentrated within a circumscribed part of the cell body close to the cell membrane. Type V is a small to medium-sized aspiny neuron. The dendrites break up into a swirling mass of thin branches. More than one axon may be given off from the soma. The axons branch close to the soma into terminal twigs. Cells of this type contain numerous large and well-stained lipofuscin granules. Each of the cell types has a characteristic pattern of pigmentation. The different varieties of nerve cells in the striatum can therefore be distinguished not only in Golgi impregnations but also in pigment-Nissl preparations.

Adult↗
PubMed1982

Neuronal types in the claustrum of man.

Neuronal types of the human claustrum have been investigated by means of a transparent Golgi technique which enables one to study the characteristics of not only the cellular processes but also the marking features of the nuclei, the cellular organelles, and the paraplasmic substances of various types of nerve cells. Five varieties of neurons have been distinguished: Type I represents a class of spiny nerve cells varying to a certain extent in size and shape. These cells contain fine and widely dispersed lipofuscin granules which can only faintly be tinged by aldehydefuchsin. Type II cells are large aspiny neurons. Their cell bodies contain a great number of deeply stained coarse pigment granules. Type III cells are large aspiny neurons devoid of pigment deposits. Type IV is a small pigment-laden aspiny neuron. Type V is a small aspiny neuron devoid of lipofuscin granules. The pattern of pigmentation revealed by the different types of nerve cells turns out to be highly characteristic. It can well be used for classification of the various types of nerve cells which occur within the reaches of the claustrum.

Adult↗
PubMed1981

On the nucleus endymalis of the human thalamus.

In the present article the shape and extent of the nucleus endymalis in the human thalamus is described. By means of a newly developed method of selective staining of intracellular lipofuscin granules with aldehydefuchsin it is possible to examine the three-dimensional shape of the griseum in complete series of 800 micrometer thick slices. The nucleus endymalis can be divided into an invariably occurring strongly pigmented caudal pars pigmentosa with clear-cut boundaries and an oral pars commissuralis. The weakly pigmented oral part is only found in brains with developed massa intermedia and varies considerably from individual to individual. The pars pigmentosa is characterized by its periventricular position medial to the nucleus parafascicularis. Differences in nomenclature and outlines of topographically corresponding thalamic nuclei of other authors are discussed. It is assumed that the pars pigmentosa a least partly corresponds to the catecholaminergic cell group A11 in the rat brain (Dahlström and Fuxe 1964). Finally, its possible functional connections to the dorsal periventricular bundle and its significance for stimulation-produced analgesia (SPA) in man are discussed.

Aged↗
PubMed1980

On the structure of IIIab-pyramidal cells in the human isocortex. A Golgi and electron microscopical study with special emphasis on the proximal axon segment.

In Golgi preparations of the adult human frontal cortex the IIIab-pyramidal cells show an apical dendrite with numerous side branches and several bifurcating basal dendrites. The dendrites are covered with numerous stalked spines. The axon takes a descending course giving rise to several collaterals. Ultrastructurally the proximal axon segment, i.e. the axon hillock and the initial segment, corresponds in a large degree to descriptions given for that of animals, including the tripartite substructure of the dense undercoating of the axolemma. In the human IIIab-pyramidal cells along the proximal part of the initial segment the undercoating displays gaps not only at the known sites but also opposite astroglial processes. The IIIab-pyramidal cells of the human isocortex require particular interest because they show almost exclusively a recently reported, age-related alteration of their proximal axon segment.

Adult↗