13 results on '"Cortical column"'
Search Results
2. Generation of dense statistical connectomes from sparse morphological data
- Author
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Robert eEgger, Vincent Jasper Dercksen, Daniel eUdvary, Hans-Christian eHege, and Marcel eOberlaender
- Subjects
Thalamus ,barrel cortex ,Dendrite ,Axon ,cortical column ,Peters’ Rule ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Human anatomy ,QM1-695 - Abstract
Sensory-evoked signal flow, at cellular and network levels, is primarily determined by the synaptic wiring of the underlying neuronal circuitry. Measurements of synaptic innervation, connection probabilities and subcellular organization of synaptic inputs are thus among the most active fields of research in contemporary neuroscience. Methods to measure these quantities range from electrophysiological recordings over reconstructions of dendrite-axon overlap at light-microscopic levels to dense circuit reconstructions of small volumes at electron-microscopic resolution. However, quantitative and complete measurements at subcellular resolution and mesoscopic scales to obtain all local and long-range synaptic in/outputs for any neuron within an entire brain region are beyond present methodological limits. Here, we present a novel concept, implemented within an interactive software environment called NeuroNet, which allows (i) integration of sparsely sampled (sub)cellular morphological data into an accurate anatomical reference frame of the brain region(s) of interest, (ii) up-scaling to generate an average dense model of the neuronal circuitry within the respective brain region(s) and (iii) statistical measurements of synaptic innervation between all neurons within the model. We illustrate our approach by generating a dense average model of the entire rat vibrissal cortex, providing the required anatomical data, and illustrate how to measure synaptic innervation statistically. Comparing our results with data from paired recordings in vitro and in vivo, as well as with reconstructions of synaptic contact sites at light- and electron-microscopic levels, we find that our in silico measurements are in line with previous results.
- Published
- 2014
- Full Text
- View/download PDF
3. MOBIUS-STRIP-LIKE COLUMNAR FUNCTIONAL CONNECTIONS ARE REVEALED IN SOMATO-SENSORY RECEPTIVE FIELD CENTROIDS.
- Author
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James Joseph Wright, Paul David Bourke, and Oleg Vyachesslavovich Favorov
- Subjects
cortical column ,Cortical development ,neuromicrocircuitry ,synaptic organization ,cortical response properties ,S1 segregates. ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Human anatomy ,QM1-695 - Abstract
Receptive fields of neurons in the forelimb region of areas 3b and 1 of primary somatosensory cortex, in cats and monkeys, were mapped using extracellular recordings obtained sequentially from nearly radial penetrations. Locations of the field centroids indicated the presence of a functional system, in which cortical homotypic representations of the limb surfaces are entwined in three-dimensional Mobius-strip-like patterns of synaptic connections. Boundaries of somatosensory receptive field in nested groups irregularly overlie the centroid order, and are interpreted as arising from the superposition of learned connections upon the embryonic order. Since the theory of embryonic synaptic self-organisation used to model these results was devised and earlier used to explain findings in primary visual cortex, the present findings suggest the theory may be of general application throughout cortex, and may reveal a modular functional synaptic system, which, only in some parts of the cortex, and in some species, is manifest as anatomical ordering into columns.
- Published
- 2014
- Full Text
- View/download PDF
4. Generation of dense statistical connectomes from sparse morphological data.
- Author
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Egger, Robert, Dercksen, Vincent J., Udvary, Daniel, Hege, Hans-Christian, and Oberlaender, Marcel
- Subjects
BRAIN mapping ,NEURAL circuitry ,SYNAPSES ,CEREBRAL cortex ,THALAMUS ,AXONS ,DENDRITES - Abstract
Sensory-evoked signal flow, at cellular and network levels, is primarily determined by the synaptic wiring of the underlying neuronal circuitry. Measurements of synaptic innervation, connection probabilities and subcellular organization of synaptic inputs are thus among the most active fields of research in contemporary neuroscience. Methods to measure these quantities range from electrophysiological recordings over reconstructions of dendrite-axon overlap at light-microscopic levels to dense circuit reconstructions of small volumes at electron-microscopic resolution. However, quantitative and complete measurements at subcellular resolution and mesoscopic scales to obtain all local and long-range synaptic in/outputs for any neuron within an entire brain region are beyond present methodological limits. Here, we present a novel concept, implemented within an interactive software environment called NeuroNet, which allows (i) integration of sparsely sampled (sub)cellular morphological data into an accurate anatomical reference frame of the brain region(s) of interest, (ii) up-scaling to generate an average dense model of the neuronal circuitry within the respective brain region(s) and (iii) statistical measurements of synaptic innervation between all neurons within the model. We illustrate our approach by generating a dense average model of the entire rat vibrissal cortex, providing the required anatomical data, and illustrate how to measure synaptic innervation statistically. Comparing our results with data from paired recordings in vitro and in vivo, as well as with reconstructions of synaptic contact sites at light- and electron-microscopic levels, we find that our in silico measurements are in line with previous results. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
5. How do you wire a brain?
- Author
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Julian eBudd and Zoltan eKisvarday
- Subjects
Axons ,Cerebral Cortex ,Dendrites ,connectome ,cortical column ,brain connectivity ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Human anatomy ,QM1-695 - Published
- 2013
- Full Text
- View/download PDF
6. Möbius-strip-like columnar functional connections are revealed in somato-sensory receptive field centroids.
- Author
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Wright, James Joseph, Bourke, Paul David, and Favorov, Oleg Vyachesslavovich
- Subjects
CONNECTIVE tissues ,EXTRACELLULAR space ,NEURONS ,NERVOUS system ,DENDRITES - Abstract
Receptive fields of neurons in the forelimb region of areas 3b and 1 of primary somatosensory cortex, in cats and monkeys, were mapped using extracellular recordings obtained sequentially from nearly radial penetrations. Locations of the field centroids indicated the presence of a functional system in which cortical homotypic representations of the limb surfaces are entwined in three-dimensional Möbius-strip-like patterns of synaptic connections. Boundaries of somatosensory receptive field in nested groups irregularly overlie the centroid order, and are interpreted as arising from the superposition of learned connections upon the embryonic order. Since the theory of embryonic synaptic self-organization used to model these results was devised and earlier used to explain findings in primary visual cortex, the present findings suggest the theory may be of general application throughout cortex and may reveal a modular functional synaptic system, which, only in some parts of the cortex, and in some species, is manifest as anatomical ordering into columns. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
7. Excitatory neuronal connectivity in the barrel cortex
- Author
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Dirk eFeldmeyer
- Subjects
Somatosensory Cortex ,barrel cortex ,cortical column ,pyramidal cell ,Excitatory connections ,long-range collaterals ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Human anatomy ,QM1-695 - Abstract
Neocortical areas are believed to be organised into vertical modules, the cortical columns, and the horizontal layers 1 to 6. In the somatosensory barrel cortex these columns are defined by the readily discernible barrel structure in layer 4. Information processing in the neocortex occurs along vertical and horizontal axes, thereby linking individual barrel-related columns via axons running through the different cortical layers of the barrel cortex. Long range signalling occurs within the neocortical layers but also through axons projecting through the white matter to other neocortical areas and subcortical brain regions. Because of the ease of identification of barrel-related columns, the rodent barrel cortex has become a prototypical system to study the interactions between different neuronal connections within a sensory cortical area and between this area and other cortical as well subcortical regions. Such interactions will be discussed specifically for the feed-forward and feedback loops between the somatosensory and the somatomotor cortices as well as the different thalamic nuclei. In addition, recent advances concerning the morphological characteristics of excitatory neurons and their impact on the synaptic connectivity patterns and signalling properties of neuronal microcircuits in the whisker-related somatosensory cortex will be reviewed. In this context, their relationship between the structural properties of barrel-related columns and their function as a module in vertical synaptic signalling in the whisker-related cortical areas will be discussed.
- Published
- 2012
- Full Text
- View/download PDF
8. Whose cortical column would that be?
- Author
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Nuno Miguel M Amorim Da Costa and Kevan Martin
- Subjects
Neuroanatomy ,cortical column ,bouton cluster ,canonical microcircuit ,Daisy ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Human anatomy ,QM1-695 - Abstract
The cortical column has been an invaluable concept to explain the functional organization of the neocortex. While this idea was born out of experiments that cleverly combined electrophysiological recordings with anatomy, no one has ‘seen’ the anatomy of a column. All we know is that when we record through the cortex of primates, ungulates, and carnivores in a trajectory perpendicular to its surface there is a remarkable constancy in the receptive field properties of the neurons regarding one set of stimulus features. There is no obvious morphological analogue for this functional architecture, in fact much of the anatomical data seems to challenge it. Here we describe historically the origins of the concept of the cortical column and the struggles of the pioneers to define the columnar architecture. We suggest that in the concept of a ‘canonical circuit’ we may find the means to reconcile the structure of neocortex with its functional architecture. The canonical microcircuit respects the known connectivity of the neocortex, and it is flexible enough to transiently change the architecture of its network in order to perform the required computation.
- Published
- 2010
- Full Text
- View/download PDF
9. Excitatory neuronal connectivity in the barrel cortex.
- Author
-
Feldmeyer, Dirk
- Subjects
CEREBRAL cortex ,NEOCORTEX ,SOMATOSENSORY cortex ,KUPFFER cells ,NEUROPLASTICITY ,CADHERINS - Abstract
Neocortical areas are believed to be organized into vertical modules, the cortical columns, and the horizontal layers 1-6. In the somatosensory barrel cortex these columns are defined by the readily discernible barrel structure in layer 4. Information processing in the neocortex occurs along vertical and horizontal axes, thereby linking individual barrel-related columns via axons running through the different cortical layers of the barrel cortex. Long-range signaling occurs within the neocortical layers but also through axons projecting through the white matter to other neocortical areas and subcortical brain regions. Because of the ease of identification of barrel-related columns, the rodent barrel cortex has become a prototypical system to study the interactions between different neuronal connections within a sensory cortical area and between this area and other cortical as well subcortical regions. Such interactions will be discussed specifically for the feed-forward and feedback loops between the somatosensory and the somatomotor cortices as well as the different thalamic nuclei. In addition, recent advances concerning the morphological characteristics of excitatory neurons and their impact on the synaptic connectivity patterns and signaling properties of neuronal microcircuits in the whisker-related somatosensory cortex will be reviewed. In this context, their relationship between the structural properties of barrel-related columns and their function as a module in vertical synaptic signaling in the whisker-related cortical areas will be discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
10. The Dendritic Density Field of a Cortical Pyramidal Cell
- Author
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Hermann Cuntz
- Subjects
Functional role ,Cortical neuron ,Computer science ,Neuroscience (miscellaneous) ,Dendrite ,lcsh:RC321-571 ,lcsh:QM1-695 ,dendrite ,Cellular and Molecular Neuroscience ,medicine ,Direct consequence ,ddc:610 ,Density field ,Axon ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,axon ,pyramidal cell ,modeling ,lcsh:Human anatomy ,Dendritic Density Field ,Neuroanatomy ,medicine.anatomical_structure ,Ramón y Cajal ,Perspective Article ,Anatomy ,Pyramidal cell ,Neuroscience ,Cortical column - Abstract
Much is known about the computation in individual neurons in the cortical column. Also, the selective connectivity between many cortical neuron types has been studied in great detail. But due to the complexity of this microcircuitry its functional role within the cortical column remains a mystery. Some of the wiring behavior between neurons can be interpreted directly from their particular dendritic and axonal shapes. Here, I describe the dendritic density field as one key element that remains to be better understood. I sketch an approach to relate dendritic density fields in general to their underlying potential connectivity schemes. As an example, I show how the characteristic shape of a cortical pyramidal cell appears as a direct consequence of connecting inputs arranged in two separate parallel layers.
- Published
- 2012
11. In Vivo Mapping of Cortical Columnar Networks in the Monkey with Focal Electrical and Optical Stimulation.
- Author
-
Roe AW, Chernov MM, Friedman RM, and Chen G
- Abstract
There are currently largescale efforts to understand the brain as a connection machine. However, there has been little emphasis on understanding connection patterns between functionally specific cortical columns. Here, we review development and application of focal electrical and optical stimulation methods combined with optical imaging and fMRI mapping in the non-human primate. These new approaches, when applied systematically on a large scale, will elucidate functionally specific intra-areal and inter-areal network connection patterns. Such functionally specific network data can provide accurate views of brain network topology.
- Published
- 2015
- Full Text
- View/download PDF
12. Whose Cortical Column Would that Be?
- Author
-
da Costa NM and Martin KA
- Abstract
The cortical column has been an invaluable concept to explain the functional organization of the neocortex. While this idea was born out of experiments that cleverly combined electrophysiological recordings with anatomy, no one has 'seen' the anatomy of a column. All we know is that when we record through the cortex of primates, ungulates, and carnivores in a trajectory perpendicular to its surface there is a remarkable constancy in the receptive field properties of the neurons regarding one set of stimulus features. There is no obvious morphological analog for this functional architecture, in fact much of the anatomical data seems to challenge it. Here we describe historically the origins of the concept of the cortical column and the struggles of the pioneers to define the columnar architecture. We suggest that in the concept of a 'canonical circuit' we may find the means to reconcile the structure of neocortex with its functional architecture. The canonical microcircuit respects the known connectivity of the neocortex, and it is flexible enough to change transiently the architecture of its network in order to perform the required computations.
- Published
- 2010
- Full Text
- View/download PDF
13. [Untitled]
- Subjects
0301 basic medicine ,Neuroscience (miscellaneous) ,Sensory system ,Granular layer ,Biology ,Somatosensory system ,Primary sensory areas ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,030104 developmental biology ,0302 clinical medicine ,medicine.anatomical_structure ,Visual cortex ,Cerebral cortex ,medicine ,Anatomy ,Receptor ,Neuroscience ,Cortical column ,030217 neurology & neurosurgery - Abstract
We measured the densities (fmol/mg protein) of 15 different receptors of various transmitter systems in the supragranular, granular and infragranular strata of 44 areas of visual, somatosensory, auditory and multimodal association systems of the human cerebral cortex. Receptor densities were obtained after labeling of the receptors using quantitative in vitro receptor autoradiography in human postmortem brains. The mean density of each receptor type over all cortical layers and of each of the three major strata varies between cortical regions. In a single cortical area, the multi-receptor fingerprints of its strata (i.e., polar plots, each visualizing the densities of multiple different receptor types in supragranular, granular or infragranular layers of the same cortical area) differ in shape and size indicating regional and laminar specific balances between the receptors. Furthermore, the three strata are clearly segregated into well definable clusters by their receptor fingerprints. Fingerprints of different cortical areas systematically vary between functional networks, and with the hierarchical levels within sensory systems. Primary sensory areas are clearly separated from all other cortical areas particularly by their very high muscarinic M2 and nicotinic alpha4beta2 receptor densities, and to a lesser degree also by noradrenergic alpha2 and serotonergic 5-HT2 receptors. Early visual areas of the dorsal and ventral streams are segregated by their multi-receptor fingerprints. The results are discussed on the background of functional segregation, cortical hierarchies, microstructural types, and the horizontal (layers) and vertical (columns) organization in the cerebral cortex. We conclude that a cortical column is composed of segments, which can be assigned to the cortical strata. The segments differ by their patterns of multi-receptor balances, indicating different layer-specific signal processing mechanisms. Additionally, the differences between the strata-and area-specific fingerprints of the 44 areas reflect the segregation of the cerebral cortex into functionally and topographically definable groups of cortical areas (visual, auditory, somatosensory, limbic, motor), and reveals their hierarchical position (primary and unimodal (early) sensory to higher sensory and finally to multimodal association areas).
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