The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Karl Zilles - One of the best experts on this subject based on the ideXlab platform.
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Cytoarchitecture and Maps of the Human Cerebral Cortex
Brain Mapping, 2015Co-Authors: Karl Zilles, Hartmut Mohlberg, Katrin Amunts, Nicola Palomero-gallagher, Sebastian BludauAbstract:This article focuses on the cytoarchitectonic organization of the cerebral cortex and its segregation into cortical areas. Cytoarchitecture describes the spatial distribution of neuronal cell types, their arrangement in horizontal layers and vertical columns, as well as cortical thickness. Based on cytoarchitectonic characteristics, the cortex is divided into iso- and allocortex, with the mesocortex as a transition region between both. Some emphasis is put on the presentation of nearly forgotten but still relevant classical cytoarchitectonic maps which are discussed in the light of recent quantitative microscopical analyses and studies of intersubject variability (probability maps) as well as functional imaging data.
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Cingulate area 32 homologies in mouse, rat, macaque and human: Cytoarchitecture and receptor architecture
The Journal of comparative neurology, 2013Co-Authors: Brent A. Vogt, Karl Zilles, Patrick R. Hof, Leslie J. Vogt, Christina Herold, Nicola Palomero-gallagherAbstract:Homologizing between human and nonhuman area 32 has been impaired since Brodmann said he could not homologize with certainty human area 32 to a specific cortical domain in other species. Human area 32 has four divisions, however, and two can be structurally homologized to nonhuman species with Cytoarchitecture and receptor architecture: pregenual (p32) and subgenual (s32) in human and macaque monkey and areas d32 and v32 in rat and mouse. Cytoarchitecture showed that areas d32/p32 have a dysgranular layer IV in all species and that areas v32/s32 have large and dense neurons in layer V, whereas a layer IV is not present in area v32. Areas v32/s32 have the largest neurons in layer Va. Features unique to humans include large layer IIIc pyramids in both divisions, sparse layer Vb in area p32, and elongated neurons in layer VI, with area s32 having the largest layer Va neurons. Receptor fingerprints of both subdivisions of area 32 differed between species in size and shape, although AMPA/GABAA and NMDA/GABAA ratios were comparable among humans, monkeys, and rats and were significantly lower than in mice. Layers I–III of primate and rodent area 32 subdivisions share more similarities in their receptor densities than layers IV–VI. Monkey and human subdivisions of area 32 are more similar to each other than to rat and mouse subdivisions. In combination with intracingulate connections, the location, Cytoarchitecture, and ligand binding studies demonstrate critical homologies among the four species. J. Comp. Neurol. 521:4189–4204, 2013. © 2013 Wiley Periodicals, Inc.
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cortical folding patterns and predicting Cytoarchitecture
Cerebral Cortex, 2008Co-Authors: Hartmut Mohlberg, Katrin Amunts, Bruce Fischl, Niranjini Rajendran, Evelina Busa, Jean C Augustinack, Oliver Hinds, B Thomas T Yeo, Karl ZillesAbstract:The human cerebral cortex is made up of a mosaic of structural areas, frequently referred to as Brodmann areas (BAs). Despite the widespread use of cortical folding patterns to perform ad hoc estimations of the locations of the BAs, little is understood regarding 1) how variable the position of a given BA is with respect to the folds, 2) whether the location of some BAs is more variable than others, and 3) whether the variability is related to the level of a BA in a putative cortical hierarchy. We use whole-brain histology of 10 postmortem human brains and surface-based analysis to test how well the folds predict the locations of the BAs. We show that higher order cortical areas exhibit more variability than primary and secondary areas and that the folds are much better predictors of the BAs than had been previously thought. These results further highlight the significance of cortical folding patterns and suggest a common mechanism for the development of the folds and the cytoarchitectonic fields.
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Cytoarchitecture of the cerebral cortex--more than localization.
NeuroImage, 2007Co-Authors: Katrin Amunts, Axel Schleicher, Karl ZillesAbstract:The present paper reviews that macroanatomical landmarks are problematic for a reliable and sufficiently precise localization of clusters of activation obtained by functional imaging because sulcal and gyral patterns are extremely variable and macroanatomical landmarks do not match (in nearly all cases) architectonically defined borders. It argues that cytoarchitectonic probabilistic maps currently offer the most precise tool for the localization of brain functions as obtained from functional imaging studies. Finally, it provides some examples that Cytoarchitecture is more than localization with respect to a particular brain region because it reflects the inner organization of cortical areas and, furthermore, functional principles of the brain.
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broca s region revisited Cytoarchitecture and intersubject variability
The Journal of Comparative Neurology, 1999Co-Authors: Katrin Amunts, Hartmut Mohlberg, Axel Schleicher, Uli Burgel, Harry B M Uylings, Karl ZillesAbstract:The sizes of Brodmann's areas 44 and 45 (Broca's speech region) and their extent in relation to macroscopic landmarks and surrounding areas differ considerably among the available cytoarchitectonic maps. Such variability may be due to intersubject differences in anatomy, observer-dependent discrepancies in cytoarchitectonic mapping, or both. Because a reliable definition of cytoarchitectonic borders is important for interpreting functional imaging data, we mapped areas 44 and 45 by means of an observer-independent technique. In 10 human brains, the laminar distributions of cell densities were measured vertical to the cortical surface in serial coronal sections stained for perikarya. Thousands of density profiles were obtained. Cytoarchitectonic borders were defined as statistically significant changes in laminar patterns. The analysis of the three-dimensional reconstructed brains and the two areas showed that cytoarchitectonic borders did not consistently coincide with sulcal contours. Therefore, macroscopic features are not reliable landmarks of cytoarchitectonic borders. Intersubject variability in the Cytoarchitecture of areas 44 and 45 was significantly greater than cytoarchitectonic differences between these areas in individual brains. Although the volumes of area 44 differed across subjects by up to a factor of 10, area 44 but not area 45 was left-over-right asymmetrical in all brains. All five male but only three of five female brains had significantly higher cell densities on the left than on the right side. Such hemispheric and gender differences were not detected in area 45. These morphologic asymmetries of area 44 provide a putative correlate of the functional lateralization of speech production. J. Comp. Neurol. 412:319–341, 1999. © 1999 Wiley-Liss, Inc.
Lilli Winter - One of the best experts on this subject based on the ideXlab platform.
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Preaged remodeling of myofibrillar Cytoarchitecture in skeletal muscle expressing R349P mutant desmin.
Neurobiology of aging, 2017Co-Authors: Stefanie Diermeier, Andreas Buttgereit, Sebastian Schürmann, Lilli Winter, Robyn M. Murphy, Christoph S. Clemen, Rolf Schröder, Oliver FriedrichAbstract:The majority of hereditary and acquired myopathies are clinically characterized by progressive muscle weakness. We hypothesized that ongoing derangement of skeletal muscle Cytoarchitecture at the single fiber level may precede and be responsible for the progressive muscle weakness. Here, we analyzed the effects of aging in wild-type (wt) and heterozygous (het) and homozygous (hom) R349P desmin knock-in mice. The latter harbor the ortholog of the most frequently encountered human R350P desmin missense mutation. We quantitatively analyzed the subcellular Cytoarchitecture of fast- and slow-twitch muscles from young, intermediate, and aged wt as well as desminopathy mice. We recorded multiphoton second harmonic generation and nuclear fluorescence signals in single muscle fibers to compare aging-related effects in all genotypes. The analysis of wt mice revealed that the myofibrillar Cytoarchitecture remained stable with aging in fast-twitch muscles, whereas slow-twitch muscle fibers displayed structural derangements during aging. In contrast, the myofibrillar Cytoarchitecture and nuclear density were severely compromised in fast- and slow-twitch muscle fibers of hom R349P desmin mice at all ages. Het mice only showed a clear degradation in their fiber structure in fast-twitch muscles from the adult to the presenescent age bin. Our study documents distinct signs of normal and R349P mutant desmin-related remodeling of the 3D myofibrillar architecture during aging, which provides a structural basis for the progressive muscle weakness.
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Plectin isoforms as organizers of intermediate filament Cytoarchitecture.
Bioarchitecture, 2011Co-Authors: Gerhard Wiche, Lilli WinterAbstract:Intermediate filaments (IFs) form cytoplamic and nuclear networks that provide cells with mechanical strength. Perturbation of this structural support causes cell and tissue fragility and accounts for a number of human genetic diseases. In recent years, important additional roles, nonmechanical in nature, were ascribed to IFs, including regulation of signaling pathways that control survival and growth of the cells, and vectorial processes such as protein targeting in polarized cellular settings. The cytolinker protein plectin anchors IF networks to junctional complexes, the nuclear envelope and cytoplasmic organelles, and it mediates their cross talk with the actin and tubulin cytoskeleton. These functions empower plectin to wield significant influence over IF network Cytoarchitecture. Moreover, the unusual diversity of plectin isoforms with different N termini and a common IF-binding (C-terminal) domain enables these isoforms to specifically associate with and thereby bridge IF networks to distinct cel...
Katrin Amunts - One of the best experts on this subject based on the ideXlab platform.
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Deep learning networks reflect cytoarchitectonic features used in brain mapping
Scientific Reports, 2020Co-Authors: Kai Kiwitz, Christian Schiffer, Hannah Spitzer, Timo Dickscheid, Katrin AmuntsAbstract:The distribution of neurons in the cortex ( Cytoarchitecture ) differs between cortical areas and constitutes the basis for structural maps of the human brain. Deep learning approaches provide a promising alternative to overcome throughput limitations of currently used cytoarchitectonic mapping methods, but typically lack insight as to what extent they follow cytoarchitectonic principles. We therefore investigated in how far the internal structure of deep convolutional neural networks trained for cytoarchitectonic brain mapping reflect traditional cytoarchitectonic features, and compared them to features of the current grey level index (GLI) profile approach. The networks consisted of a 10-block deep convolutional architecture trained to segment the primary and secondary visual cortex. Filter activations of the networks served to analyse resemblances to traditional cytoarchitectonic features and comparisons to the GLI profile approach. Our analysis revealed resemblances to cellular, laminar- as well as cortical area related cytoarchitectonic features. The networks learned filter activations that reflect the distinct Cytoarchitecture of the segmented cortical areas with special regard to their laminar organization and compared well to statistical criteria of the GLI profile approach. These results confirm an incorporation of relevant cytoarchitectonic features in the deep convolutional neural networks and mark them as a valid support for high-throughput cytoarchitectonic mapping workflows.
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Cytoarchitecture and Maps of the Human Cerebral Cortex
Brain Mapping, 2015Co-Authors: Karl Zilles, Hartmut Mohlberg, Katrin Amunts, Nicola Palomero-gallagher, Sebastian BludauAbstract:This article focuses on the cytoarchitectonic organization of the cerebral cortex and its segregation into cortical areas. Cytoarchitecture describes the spatial distribution of neuronal cell types, their arrangement in horizontal layers and vertical columns, as well as cortical thickness. Based on cytoarchitectonic characteristics, the cortex is divided into iso- and allocortex, with the mesocortex as a transition region between both. Some emphasis is put on the presentation of nearly forgotten but still relevant classical cytoarchitectonic maps which are discussed in the light of recent quantitative microscopical analyses and studies of intersubject variability (probability maps) as well as functional imaging data.
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cortical folding patterns and predicting Cytoarchitecture
Cerebral Cortex, 2008Co-Authors: Hartmut Mohlberg, Katrin Amunts, Bruce Fischl, Niranjini Rajendran, Evelina Busa, Jean C Augustinack, Oliver Hinds, B Thomas T Yeo, Karl ZillesAbstract:The human cerebral cortex is made up of a mosaic of structural areas, frequently referred to as Brodmann areas (BAs). Despite the widespread use of cortical folding patterns to perform ad hoc estimations of the locations of the BAs, little is understood regarding 1) how variable the position of a given BA is with respect to the folds, 2) whether the location of some BAs is more variable than others, and 3) whether the variability is related to the level of a BA in a putative cortical hierarchy. We use whole-brain histology of 10 postmortem human brains and surface-based analysis to test how well the folds predict the locations of the BAs. We show that higher order cortical areas exhibit more variability than primary and secondary areas and that the folds are much better predictors of the BAs than had been previously thought. These results further highlight the significance of cortical folding patterns and suggest a common mechanism for the development of the folds and the cytoarchitectonic fields.
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Cytoarchitecture of the cerebral cortex--more than localization.
NeuroImage, 2007Co-Authors: Katrin Amunts, Axel Schleicher, Karl ZillesAbstract:The present paper reviews that macroanatomical landmarks are problematic for a reliable and sufficiently precise localization of clusters of activation obtained by functional imaging because sulcal and gyral patterns are extremely variable and macroanatomical landmarks do not match (in nearly all cases) architectonically defined borders. It argues that cytoarchitectonic probabilistic maps currently offer the most precise tool for the localization of brain functions as obtained from functional imaging studies. Finally, it provides some examples that Cytoarchitecture is more than localization with respect to a particular brain region because it reflects the inner organization of cortical areas and, furthermore, functional principles of the brain.
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broca s region revisited Cytoarchitecture and intersubject variability
The Journal of Comparative Neurology, 1999Co-Authors: Katrin Amunts, Hartmut Mohlberg, Axel Schleicher, Uli Burgel, Harry B M Uylings, Karl ZillesAbstract:The sizes of Brodmann's areas 44 and 45 (Broca's speech region) and their extent in relation to macroscopic landmarks and surrounding areas differ considerably among the available cytoarchitectonic maps. Such variability may be due to intersubject differences in anatomy, observer-dependent discrepancies in cytoarchitectonic mapping, or both. Because a reliable definition of cytoarchitectonic borders is important for interpreting functional imaging data, we mapped areas 44 and 45 by means of an observer-independent technique. In 10 human brains, the laminar distributions of cell densities were measured vertical to the cortical surface in serial coronal sections stained for perikarya. Thousands of density profiles were obtained. Cytoarchitectonic borders were defined as statistically significant changes in laminar patterns. The analysis of the three-dimensional reconstructed brains and the two areas showed that cytoarchitectonic borders did not consistently coincide with sulcal contours. Therefore, macroscopic features are not reliable landmarks of cytoarchitectonic borders. Intersubject variability in the Cytoarchitecture of areas 44 and 45 was significantly greater than cytoarchitectonic differences between these areas in individual brains. Although the volumes of area 44 differed across subjects by up to a factor of 10, area 44 but not area 45 was left-over-right asymmetrical in all brains. All five male but only three of five female brains had significantly higher cell densities on the left than on the right side. Such hemispheric and gender differences were not detected in area 45. These morphologic asymmetries of area 44 provide a putative correlate of the functional lateralization of speech production. J. Comp. Neurol. 412:319–341, 1999. © 1999 Wiley-Liss, Inc.
Gerhard Wiche - One of the best experts on this subject based on the ideXlab platform.
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Plectin isoforms as organizers of intermediate filament Cytoarchitecture.
Bioarchitecture, 2011Co-Authors: Gerhard Wiche, Lilli WinterAbstract:Intermediate filaments (IFs) form cytoplamic and nuclear networks that provide cells with mechanical strength. Perturbation of this structural support causes cell and tissue fragility and accounts for a number of human genetic diseases. In recent years, important additional roles, nonmechanical in nature, were ascribed to IFs, including regulation of signaling pathways that control survival and growth of the cells, and vectorial processes such as protein targeting in polarized cellular settings. The cytolinker protein plectin anchors IF networks to junctional complexes, the nuclear envelope and cytoplasmic organelles, and it mediates their cross talk with the actin and tubulin cytoskeleton. These functions empower plectin to wield significant influence over IF network Cytoarchitecture. Moreover, the unusual diversity of plectin isoforms with different N termini and a common IF-binding (C-terminal) domain enables these isoforms to specifically associate with and thereby bridge IF networks to distinct cel...
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oxidation and nitrosylation of cysteines proximal to the intermediate filament if binding site of plectin effects on structure and vimentin binding and involvement in if collapse
Journal of Biological Chemistry, 2007Co-Authors: Radovan Spurny, Kamaran Abdoulrahman, Lubomir Janda, Dominik Runzler, Gottfried Kohler, Maria J Castanon, Gerhard WicheAbstract:Abstract As an intermediate filament (IF)-based cytolinker protein, plectin plays a key role in the maintenance of cellular Cytoarchitecture and serves at the same time as a scaffolding platform for signaling cascades. Consisting of six structural repeats (R1–6) and harboring binding sites for different IF proteins and proteins involved in signaling, the plectin C-terminal domain is of strategic functional importance. Depending on the species, it contains at least 13 cysteines, 4 of which reside in the R5 domain. To investigate the structural and biological functions of R5 cysteines, we used cysteine-to-serine mutagenesis and spectroscopic, biochemical, and functional analyses. Urea-induced unfolding experiments indicated that wild-type R5 in the oxidized, disulfide bond-mediated conformation was more stable than its cysteine-free mutant derivative. The binding affinity of R5 for vimentin was significantly higher, however, when the protein was in the reduced, more relaxed conformation. Of the four R5 cysteines, one (Cys4) was particularly reactive as reflected by its ability to form disulfide bridges with R5 Cys1 and to serve as a target for nitrosylation in vitro. Using immortalized endothelial cell cultures from mice, we show that endogenous plectin is nitrosylated in vivo, and we found that NO donor-induced IF collapse proceeds dramatically faster in plectin-deficient compared with wild-type cells. Our data suggest an antagonistic role of plectin in nitrosylation (oxidative stress)-mediated alterations of IF Cytoarchitecture and a possible role of R5 Cys4 as a regulatory switch.
Rashmi Kothary - One of the best experts on this subject based on the ideXlab platform.
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Dystonin-deficient mice exhibit an intrinsic muscle weakness and an instability of skeletal muscle Cytoarchitecture.
Developmental biology, 1999Co-Authors: Gratien Dalpé, Martine Mathieu, Alain Comtois, Ercheng Zhu, Sylwia Wasiak, Yves De Repentigny, Nicole Leclerc, Rashmi KotharyAbstract:Dystonia musculorum (dt) was originally described as a hereditary sensory neurodegeneration syndrome of the mouse. The gene defective in dt encodes a cytoskeletal linker protein, dystonin, that is essential for maintaining neuronal cytoskeletal integrity. In addition to the nervous system, dystonin is expressed in a variety of other tissues, including muscle. We now show that dystonin cross-links actin and desmin filaments and that its levels are increased during myogenesis, coinciding with the progressive reorganization of the intermediate filament network. A disorganization of Cytoarchitecture in skeletal muscle from dt/dt mice was observed in ultrastructural studies. Myoblasts from dt/dt mice fused to form myotubes in culture; however, terminally differentiated myotubes contained incompletely assembled myofibrils. Another feature observed in dt/dt myotubes in culture and in skeletal muscle in situ was an accumulation and abnormal distribution of mitochondria. The diaphragm muscle from dt/dt mice was weak in isometric contractility measurements in vitro and was susceptible to contraction-induced sarcolemmal damage. Altogether, our data indicate that dystonin is a cross-linker of actin and desmin filaments in muscle and that it is essential for establishing and maintaining proper Cytoarchitecture in mature muscle.
