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PubMed1981

Cortical structure of the lymph node. I. Effect of blockage of the afferent lymph flow to mouse popliteal nodes for protracted periods.

Changes in the lymphoid organization of the popliteal lymph nodes in mice, under conditions where the afferent lymph flow to the nodes was kept blocked for a protracted period, were the subject of this study. Surgical operations to interrupt the afferent lymphatics of the popliteal nodes were performed and the afferent lymph flow remained blocked for 15 weeks after the operation. A striking accumulation of small lymphocytes occurred within the nodes and the cellular density of the parenchyma and lumina of the sinuses greatly increased. These changes persisted throughout the 15 weeks period of observation. Germinal centres gradually diminished in size and ultimately disappeared completely from most of the operated nodes. Lymphatic nodules, which were aggregations of B lymphocytes, decreased in size to some extent but the number of these structures per whole node was not significantly different from that of the unoperated node. The deep cortex remained highly populated with small lymphocytes and showed no indication of fading out or of being replaced by the medullary structures.

Animals↗
PubMed1995

Constancy and variability in cortical structure. A study on synapses and dendritic spines in hedgehog and monkey.

Synapses and dendritic spines were investigated in the parietal cortex of the hedgehog (Erinaceus europaeus) and the monkey (Macaca mulatta). There was no significant difference in the density of synapses between the two species (14 synapses/100 microns2 in the hedgehog, 15/100 microns2 in the monkey), neither in the size of the synaptic junctions, in the proportion of Type I and Type II synapses (8-10% were of Type II in the hedgehog, 10-14% in the monkey) nor in the proportion of perforated synapses (8% in the hedgehog, 5% in the monkey). The only striking difference at the electron microscopic level concerned the frequency of synapses in which the postsynaptic profile was deeply indented into the presynaptic terminal. Such synapses were 10 times more frequent in the monkey. Dendritic spines were investigated in Golgi-preparations. The density of spines along dendrites was similar in both species. The results are discussed with regard to connectivity in the cortex of small and large brains.

Animals↗
PubMed1976

[A method of assessing the degree of vertical organization of cerebral cortical structures].

A method of obtaining a comparative quantitative evaluation of the vertical order of neurons in the cerebral cortex structures with the help ofinformational indices of the entropy and organization is proposed. The presence of the vertical column order of neurons is considered as a manifestation of a certain general regularly in the building of neural complexes. The morphological preparation (section) of the definitive process. The scheme of operations with the given record (morphological preparation) in the uork permits obtaining the values of the entropy and organization. In the example of the middle of layer III field 17 and sublayer III2 of layer 18 of the human new cortex it has been shown that the proposed method contributes to revealing the difference in the degree of the vertical order of neurons in these structures.

Cerebral Cortex↗
PubMed1990

Spectrin, actin and the structure of the cortical lattice in mammalian cochlear outer hair cells.

Mammalian cochlear outer hair cells generate high-frequency forces in response to electrical stimulation. Force generation occurs in the lateral cortex of the cell, which includes the plasma membrane, a two-dimensional 'cortical lattice' of filamentous protein, and a multi-layered membrane system, the lateral cisternae. The cortical lattice is composed of relatively long filaments, 6.7 nm in diameter, which are wound circumferentially about the cell. These filaments are spaced about 42 nm apart and are cross-linked by a second type of filament 3.2 nm in diameter approximately aligned with the longitudinal axis of the cell. The cortical lattice is the only cortical structure that remains after the cell is fully extracted in the detergent Triton X-100 and high-salt solution. It retains the original cylindrical shape of the cell and is reversibly deformable. Antibodies raised against chicken gizzard actin, human blood spectrin and pig brain spectrin all react positively with the extracted lattice viewed using immunofluorescence. Three protein subunits identified in the organ of Corti have approximate molecular weights of 220, 235 and 240K (K = 10(3) Mr) and react with the spectrin antibodies. A structural model of the lattice is proposed in which the circumferential filaments are composed of actin and the cross-linked of spectrin. The model can account for the unusual cylindrical shape of outer hair cells and suggests a mechanism of force generation based upon the elastic and electrostatic properties of spectrin.

Actins↗
PubMed2002

Mapping cortical columnar structures using fMRI.

Mapping cortical columnar structures is important to understand cortical information processing. To map submillimeter columnar structures noninvasively, we have evaluated various functional magnetic resonance imaging (fMRI) techniques using a well-established feline orientation column model. The conventional positive blood oxygenation level-dependent (BOLD) signal is widespread and diffuse due to large venous vessel contributions, resulting in its poor specificity to columns. However, the early-negative BOLD signal is induced by the early oxygen consumption increase without significant change in blood flow. This negative signal has been successfully applied for columnar mapping. Tissue-specific cerebral blood flow (CBF) response is also specific to individual cortical columns, suggesting that parenchyma-specific fMRI techniques are capable to map individual single-condition functional cortical columns in animals as well as humans.

Animals↗
PubMed1984

Comparison of brain structure volumes in insectivora and primates. IV. Non-cortical visual structures.

The relative size of the eyes, optic nerves, chiasms and tracts, and of the dorsal nucleus of the lateral geniculate body is distinctly larger in Primates than in (theoretically) isoponderous Insectivora. Within Insectivora, the relative size is lowest in moles, medium in shrews and hedgehog-like tenrecs, and largest in hedgehogs. Within Primates, all relative sizes are on the average larger in simians than in prosimians: the eyes to a small degree, the lateral geniculate bodies moderately and the optic nerves considerably larger. The ratio between eyes and optic nerves is large in night-active primates and distinctly smaller in day-active forms, with no overlap. The only night-active simian (Aotus trivirgatus) is in line with night-active prosimians. The relative size of the non-cortical visual structures in man is in line with that of day-active simians, whereas two of the great apes (orang-utan and gorilla) are relatively low. The size of the visual structures appears to depend mainly on functional requirements and is not, or is distinctly less, related to differences in the evolutionary level. The size of the visual structures of tree-shrews (Scandentia) shows special features which are not found in Insectivora and Primates and is compatible with their separation from these orders.

Animals↗
PubMed1988

The basolateral amygdaloid complex as a cortical-like structure.

The thalamic innervation of the rat basolateral amygdaloid complex was studied with a combination of light- and electron microscopic techniques using anterogradely transported Phaseolus vulgaris-leucoagglutinin (PHA-L) as well as combined degeneration and single-section Golgi impregnation for the identification of thalamo-amygdaloid synaptic relations. The results indicated that the basolateral amygdaloid nucleus corresponds in several features to a cortical structure. Like all cortical areas, the basolateral amygdaloid nucleus is reciprocally related to other cortical regions as well as to the thalamus.

Amygdala↗
PubMed2002

[Possibilities and limitations of ultrasonography in corticotomy/callus distraction].

Sonographic examination can yield additional information free of radiation in the course of corticotomy/callus distraction. The echogenic structures of the cortical structure and the callus between can be scanned at the area of the callus distraction by ultrasound examination. Individual sectional planes are focussed. They are different from the standardized ultrasound examination. Depending on when the corticotomy was performed, the callus between the cortical structures can be visualized sonographically. First it is echo poor, and then it becomes more and more echogenic. The ultrasound examination can give additional information during the first 4 weeks after corticotomy/callus distraction. A deviation of the axis in the area of callus distraction cannot be judged reliably. A sonographically guided division into three stages is possible.

Bony Callus↗
PubMed2004

The role of sub-cortical brain structures in emotion recognition.

PRIMARY OBJECTIVE: This study investigated the role of sub-cortical brain structures in emotion recognition. METHODS AND PROCEDURES: Fourteen patients (eight left, six right) with sub-cortical brain damage (SS) and 14 matched healthy volunteers (HV) were recruited. A brief neuropsychological battery was administered to measure working memory, visual inattention, Stroop effect and visual organization. A facial and prosodic emotion recognition battery previously developed was used. RESULTS: SS patients were generally impaired on emotion recognition, with the exception of facial emotion discrimination and tasks involving happy expressions, relative to HV. Preliminary analyses also showed no statistical difference between patients with left- and right-sub-cortical brain damage in terms of emotion recognition. CONCLUSIONS: The findings provide further support for the role of sub-cortical brain structures (and the damage thereof) as well as probable frontal-limbic neural networks in recognizing basic emotions.

Aged↗
PubMed1963

Location and composition of spore mucopeptide in Bacillus species.

Spore integuments of Bacillus coagulans were prepared containing nearly all the hexosamine and alpha, epsilon-diaminopimelic acid (DAP) present in intact spores. Subsequent autolytic action resulted in the destruction and removal of the residual cortical structure and "cortical membrane" leaving the appearance of the inner and outer spore coats unchanged in electron micrographs. Concurrently, all the hexosamine and DAP in the preparation was released mainly as non-diffusible mucopeptide containing alanine, glutamic acid, DAP, and all the glucosamine and muramic acid. Some diffusible peptides containing alanine, glutamic acid, and DAP were also present but there was little protein or carbohydrate. Lysozyme digestion of integument preparations from heated spores of Bacillus 636, B. subtilis, B. coagulans, and B. stearothermophilus specifically removed the residual cortex and cortical membrane with the release of the mucopeptide. In B. cereus T, only the residual cortex and part of the mucopeptide were solubilized by lysozyme. The effect of several reagents and enzymes upon the appearance and removal of hexosamine from B. coagul ans spore integuments is reported. The results show that spore mucopeptide is mainly located in the residual cortex and cortical membrane and suggest that these structures consist essentially of mucopeptide. The implications of these results in relation to the "contractile cortex" theory of heat resistance in spores are discussed.

Bacillus↗
PubMed1997

Influences on the global structure of cortical maps.

Cortical maps often contain global spatial structure: however, theoretical accounts for their development have generally concentrated on reproducing only local structure. We show that the elastic net model of cortical map formation can closely approximate the global structure of the ocular dominance column map observed in macaque primary visual cortex. A key component is the assumption of spatially non-uniform and anisotropic correlations in the retina. This work shows how genetic and epigenetic effects could combine to establish characteristic global structure in cortical maps.

Animals↗
PubMed2006

Molecular markers of neuronal progenitors in the embryonic cerebellar anlage.

The cerebellum, like the cerebrum, includes a nuclear structure and an overlying cortical structure. Experiments in the past decade have expanded knowledge beyond the traditional function of the cerebellum to include critical roles in motor learning and memory and sensory discrimination. The initial steps in cerebellar development depend on inductive signaling involving FGF and Wnt proteins produced at the mesencephalic/metencephalic boundary. To address the issue of how individual cerebellar cell fates within the cerebellar territory are specified, we examined the expression of transcription factors, including mammalian homologues of LIM homeodomain-containing proteins, basic helix-loop-helix proteins, and three amino acid loop-containing proteins. The results of these studies show that combinatorial codes of transcription factors define precursors of the cerebellar nuclei, and both Purkinje cells and granule neurons of the cerebellar cortex. Examination of gene expression patterns in several hundred lines of Egfp-BAC (bacterial artificial chromosome) transgenic mice in the GENSAT Project revealed numerous genes with restricted expression in cerebellar progenitor populations, including genes specific for cerebellar nuclear precursors and Purkinje cell precursors. In addition, we identified patterns of gene expression that link granule and Purkinje cells to their precerebellar nuclei. These results identify molecular pathways that offer new insights on the development of the nuclear and cortical structures of the cerebellum, as well as components of the cerebellar circuitry.

Animals↗
PubMed2002

Fascins, and their roles in cell structure and function.

The fascins are a structurally unique and evolutionarily conserved group of actin cross-linking proteins. Fascins function in the organisation of two major forms of actin-based structures: dynamic, cortical cell protrusions and cytoplasmic microfilament bundles. The cortical structures, which include filopodia, spikes, lamellipodial ribs, oocyte microvilli and the dendrites of dendritic cells, have roles in cell-matrix adhesion, cell interactions and cell migration, whereas the cytoplasmic actin bundles appear to participate in cell architecture. We discuss the current understanding of the cellular mechanisms that regulate the binding of fascin to actin and how these processes contribute to the organisation or disassembly of cell protrusions. Although the in vivo roles of fascin have been studied principally in Drosophila, several human diseases are associated with inherited or acquired alterations in the expression of fascins. Strategies to modulate fascin-containing protrusions and thereby cell adhesive and migratory behaviour could have potential for therapeutic intervention in these conditions. The supplementary material referred to in this section can be found at http://www.interscience.wiley.com/jpages/0265-9247/suppmat/2002/v24.350.html

Actins↗
PubMed1996

Melanocortins and lesion-induced plasticity in the CNS: a review.

This review summarises and critically evaluates the literature pertaining to the actions of short fragments of the adrenocorticotropic hormone (ACTH) ("melanocortins') on lesion-induced plasticity in the central nervous system (CNS). The majority of the evidence suggests that melanocortins are more effective in enhancing recovery from lesions of subcortical structures than cortical structures, although there is substantial variability in findings depending upon the specific ACTH fragment used and the way in which it is administered. Five specific melanocortin (MC) receptors have been identified, however, the evidence to date suggests that short ACTH fragments may not enhance lesion-induced plasticity in the CNS via these MC receptor subtypes. It is possible that another, as yet unidentified, MC receptor subtype is involved, or else that some short ACTH fragments act allosterically on another receptor type (e.g., the N-methyl-D-asparate (NMDA) receptor).

Adrenocorticotropic Hormone↗