12,833 research outputs found
1st INCF Workshop on Neuroanatomical Nomenclature and Taxonomy
The goal of this workshop was to agree on a general strategy for developing a systematic, useful, and scientifically appropriate framework for neuroanatomical nomenclature. The workshop focused on general principles that will serve as a basis for future decisions on implementation strategies. The report discusses the problems arising from the use of different parcellation schemes and use of different terminologies and highlights the need of a universal vocabulary for describing the structural organization of the nervous system. Workshop participants encourage the creation of an International Coordinating Committee for Neuroanatomical Nomenclature and propose short- and long-term goals for such a committee
In praise of tedious anatomy
Functional neuroimaging is fundamentally a tool for mapping function to structure, and its success consequently requires neuroanatomical precision and accuracy. Here we review the various means by which functional activation can be localized to neuroanatomy and suggest that the gold standard should be localization to the individual’s or group’s own anatomy through the use of neuroanatomical knowledge and atlases of neuroanatomy. While automated means of localization may be useful, they cannot provide the necessary accuracy, given variability between individuals. We also suggest that the field of functional neuroimaging needs to converge on a common set of methods for reporting functional localization including a common “standard” space and criteria for what constitutes sufficient evidence to report activation in terms of Brodmann’s areas
Abnormal white matter tracts resembling pencil fibers involving prefrontal cortex (Brodmann area 47) in autism: a case report.
BackgroundAutism is not correlated with any neuropathological hallmark as the brain of autistic individuals lack defined lesions. However, previous investigations have reported cortical heterotopias and local distortion of the cytoarchitecture of the neocortex in some cases of autism.Case presentationOur patient was a 40-year-old white woman diagnosed at an early age with autism and mental retardation. Pencil fibers were present within the prefrontal cortex (Brodmann area 47) and its composition resembled that of the underlying white matter region. Pencil fibers encompassed most of the extent of the cortical grey matter and were populated by oligodendrocytes, astrocytes, and microglial cells, but not by neurons.ConclusionsHere we report a new cytoarchitectural abnormality that has not been previously described in autism. Future pathological examinations should keep in mind the potential presence of pencil fibers within the prefrontal cortex of cases with autism
Quantitative assessment of prefrontal cortex in humans relative to nonhuman primates
Significance
A longstanding controversy in neuroscience pertains to differences in human prefrontal cortex (PFC) compared with other primate species; specifically, is human PFC disproportionately large? Distinctively human behavioral capacities related to higher cognition and affect presumably arose from evolutionary modifications since humans and great apes diverged from a common ancestor about 6–8 Mya. Accurate determination of regional differences in the amount of cortical gray and subcortical white matter content in humans, great apes, and Old World monkeys can further our understanding of the link between structure and function of the human brain. Using tissue volume analyses, we show a disproportionately large amount of gray and white matter corresponding to PFC in humans compared with nonhuman primates.</jats:p
Cell proliferation, cell shape, and microtubule and cellulose microfibril organization of tobacco BY-2 cells are not altered by exposure to near weightlessness in space
The microtubule cytoskeleton and the cell wall both play key roles in plant cell growth and division, determining the plant’s final stature. At near weightlessness, tubulin polymerizes into microtubules in vitro, but these microtubules do not self-organize in the ordered patterns observed at 1g. Likewise, at near weightlessness cortical microtubules in protoplasts have difficulty organizing into parallel arrays, which are required for proper plant cell elongation. However, intact plants do grow in space and therefore should have a normally functioning microtubule cytoskeleton. Since the main difference between protoplasts and plant cells in a tissue is the presence of a cell wall, we studied single, but walled, tobacco BY-2 suspension-cultured cells during an 8-day space-flight experiment on board of the Soyuz capsule and the International Space Station during the 12S mission (March–April 2006). We show that the cortical microtubule density, ordering and orientation in isolated walled plant cells are unaffected by near weightlessness, as are the orientation of the cellulose microfibrils, cell proliferation, and cell shape. Likely, tissue organization is not essential for the organization of these structures in space. When combined with the fact that many recovering protoplasts have an aberrant cortical microtubule cytoskeleton, the results suggest a role for the cell wall, or its production machinery, in structuring the microtubule cytoskeleto
Molecular dissection of the mechanism by which EWS/FLI expression compromises actin cytoskeletal integrity and cell adhesion in Ewing sarcoma.
Ewing sarcoma is the second-most-common bone cancer in children. Driven by an oncogenic chromosomal translocation that results in the expression of an aberrant transcription factor, EWS/FLI, the disease is typically aggressive and micrometastatic upon presentation. Silencing of EWS/FLI in patient-derived tumor cells results in the altered expression of hundreds to thousands of genes and is accompanied by dramatic morphological changes in cytoarchitecture and adhesion. Genes encoding focal adhesion, extracellular matrix, and actin regulatory proteins are dominant targets of EWS/FLI-mediated transcriptional repression. Reexpression of genes encoding just two of these proteins, zyxin and α5 integrin, is sufficient to restore cell adhesion and actin cytoskeletal integrity comparable to what is observed when the EWS/FLI oncogene expression is compromised. Using an orthotopic xenograft model, we show that EWS/FLI-induced repression of α5 integrin and zyxin expression promotes tumor progression by supporting anchorage-independent cell growth. This selective advantage is paired with a tradeoff in which metastatic lung colonization is compromised
Grey-matter texture abnormalities and reduced hippocampal volume are distinguishing features of schizophrenia
Neurodevelopmental processes are widely believed to underlie schizophrenia. Analysis of
brain texture from conventional magnetic resonance imaging (MRI) can detect disturbance in
brain cytoarchitecture. We tested the hypothesis that patients with schizophrenia manifest
quantitative differences in brain texture that, alongside discrete volumetric changes, may
serve as an endophenotypic biomarker. Texture analysis (TA) of grey matter distribution and
voxel-based morphometry (VBM) of regional brain volumes were applied to MRI scans of 27
patients with schizophrenia and 24 controls. Texture parameters (uniformity and entropy)
were also used as covariates in VBM analyses to test for correspondence with regional brain
volume. Linear discriminant analysis tested if texture and volumetric data predicted
diagnostic group membership (schizophrenia or control). We found that uniformity and
entropy of grey matter differed significantly between individuals with schizophrenia and
controls at the fine spatial scale (filter width below 2 mm). Within the schizophrenia group,
these texture parameters correlated with volumes of the left hippocampus, right amygdala
and cerebellum. The best predictor of diagnostic group membership was the combination of
fine texture heterogeneity and left hippocampal size. This study highlights the presence of
distributed grey-matter abnormalities in schizophrenia, and their relation to focal structural
abnormality of the hippocampus. The conjunction of these features has potential as a
neuroimaging endophenotype of schizophrenia
Construction of 3D in vitro models by bioprinting human pluripotent stem cells: Challenges and opportunities
Three-dimensional (3D) printing of biological material, or 3D bioprinting, is a rapidly expanding field with interesting applications in tissue engineering and regenerative medicine. Bioprinters use cells and biocompatible materials as an ink (bioink) to build 3D structures representative of organs and tissues, in a controlled manner and with micrometric resolution. Human embryonic (hESCs) and induced (hiPSCs) pluripotent stem cells are ideally able to provide all cell types found in the human body. A limited, but growing, number of recent reports suggest that cells derived by differentiation of hESCs and hiPSCs can be used as building blocks in bioprinted human 3D models, reproducing the cellular variety and cytoarchitecture of real tissues. In this review we will illustrate these examples, which include hepatic, cardiac, vascular, corneal and cartilage tissues, and discuss challenges and opportunities of bioprinting more demanding cell types, such as neurons, obtained from human pluripotent stem cells
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