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Edvard I. Moser - One of the best experts on this subject based on the ideXlab platform.
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Spatial Representation in the hippocampal formation a history
Nature Neuroscience, 2017Co-Authors: Edvard I. Moser, May-britt Moser, Bruce L McnaughtonAbstract:Since the first place cell was recorded and the cognitive-map theory was subsequently formulated, investigation of Spatial Representation in the hippocampal formation has evolved in stages. Early studies sought to verify the Spatial nature of place cell activity and determine its sensory origin. A new epoch started with the discovery of head direction cells and the realization of the importance of angular and linear movement-integration in generating Spatial maps. A third epoch began when investigators turned their attention to the entorhinal cortex, which led to the discovery of grid cells and border cells. This review will show how ideas about integration of self-motion cues have shaped our understanding of Spatial Representation in hippocampal-entorhinal systems from the 1970s until today. It is now possible to investigate how specialized cell types of these systems work together, and Spatial mapping may become one of the first cognitive functions to be understood in mechanistic detail.
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Spatial Representation along the proximodistal axis of ca1
Neuron, 2010Co-Authors: Espen J Henriksen, May-britt Moser, Menno P. Witter, Laura Lee Colgin, Carol A Barnes, Edvard I. MoserAbstract:CA1 cells receive direct input from space-responsive cells in medial entorhinal cortex (MEC), such as grid cells, as well as more nonSpatial cells in lateral entorhinal cortex (LEC). Because MEC projects preferentially to the proximal part of the CA1, bordering CA2, whereas LEC innervates only the distal part, bordering subiculum, we asked if Spatial tuning is graded along the transverse axis of CA1. Tetrodes were implanted along the entire proximodistal axis of dorsal CA1 in rats. Data were recorded in cylinders large enough to elicit firing at more than one location in many neurons. Distal CA1 cells showed more dispersed firing and had a larger number of firing fields than proximal cells. Phase-locking of spikes to MEC theta oscillations was weaker in distal CA1 than in proximal CA1. The findings suggest that Spatial firing in CA1 is organized transversally, with the strongest Spatial modulation occurring in the MEC-associated proximal part.
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development of the Spatial Representation system in the rat
Science, 2010Co-Authors: Rosamund F Langston, Edvard I. Moser, Menno P. Witter, James A Ainge, Jonathan J Couey, Cathrin B Canto, Tale Litlere Bjerknes, May-britt MoserAbstract:In the adult brain, space and orientation are represented by an elaborate hippocampal-parahippocampal circuit consisting of head-direction cells, place cells, and grid cells. We report that a rudimentary map of space is already present when 2½-week-old rat pups explore an open environment outside the nest for the first time. Head-direction cells in the pre- and parasubiculum have adultlike properties from the beginning. Place and grid cells are also present but evolve more gradually. Grid cells show the slowest development. The gradual refinement of the Spatial Representation is accompanied by an increase in network synchrony among entorhinal stellate cells. The presence of adultlike directional signals at the onset of navigation raises the possibility that such signals are instrumental in setting up networks for place and grid Representation.
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finite scale of Spatial Representation in the hippocampus
Science, 2008Co-Authors: Kirsten Brun Kjelstrup, Edvard I. Moser, Menno P. Witter, Trygve Solstad, Vegard Heimly Brun, Torkel Hafting, Stefan Leutgeb, May-britt MoserAbstract:To determine how Spatial scale is represented in the pyramidal cell population of the hippocampus, we recorded neural activity at multiple longitudinal levels of this brain area while rats ran back and forth on an 18-meter-long linear track. CA3 cells had well-defined place fields at all levels. The scale of Representation increased almost linearly from <1 meter at the dorsal pole to ∼10 meters at the ventral pole. The results suggest that the place-cell map includes the entire hippocampus and that environments are represented in the hippocampus at a topographically graded but finite continuum of scales.
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impaired Spatial Representation in ca1 after lesion of direct input from entorhinal cortex
Neuron, 2008Co-Authors: Vegard Heimly Brun, Edvard I. Moser, Menno P. Witter, Stefan Leutgeb, Robert Schwarcz, May-britt MoserAbstract:Place-specific firing in the hippocampus is determined by path integration-based Spatial Representations in the grid-cell network of the medial entorhinal cortex. Output from this network is conveyed directly to CA1 of the hippocampus by projections from principal neurons in layer III, but also indirectly by axons from layer II to the dentate gyrus and CA3. The direct pathway is sufficient for Spatial firing in CA1, but it is not known whether similar firing can also be supported by the input from CA3. To test this possibility, we made selective lesions in layer III of medial entorhinal cortex by local infusion of the neurotoxin gamma-acetylenic GABA. Firing fields in CA1 became larger and more dispersed after cell loss in layer III, whereas CA3 cells, which receive layer II input, still had sharp firing fields. Thus, the direct projection is necessary for precise Spatial firing in the CA1 place cell population.
May-britt Moser - One of the best experts on this subject based on the ideXlab platform.
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Spatial Representation in the hippocampal formation a history
Nature Neuroscience, 2017Co-Authors: Edvard I. Moser, May-britt Moser, Bruce L McnaughtonAbstract:Since the first place cell was recorded and the cognitive-map theory was subsequently formulated, investigation of Spatial Representation in the hippocampal formation has evolved in stages. Early studies sought to verify the Spatial nature of place cell activity and determine its sensory origin. A new epoch started with the discovery of head direction cells and the realization of the importance of angular and linear movement-integration in generating Spatial maps. A third epoch began when investigators turned their attention to the entorhinal cortex, which led to the discovery of grid cells and border cells. This review will show how ideas about integration of self-motion cues have shaped our understanding of Spatial Representation in hippocampal-entorhinal systems from the 1970s until today. It is now possible to investigate how specialized cell types of these systems work together, and Spatial mapping may become one of the first cognitive functions to be understood in mechanistic detail.
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Spatial Representation along the proximodistal axis of ca1
Neuron, 2010Co-Authors: Espen J Henriksen, May-britt Moser, Menno P. Witter, Laura Lee Colgin, Carol A Barnes, Edvard I. MoserAbstract:CA1 cells receive direct input from space-responsive cells in medial entorhinal cortex (MEC), such as grid cells, as well as more nonSpatial cells in lateral entorhinal cortex (LEC). Because MEC projects preferentially to the proximal part of the CA1, bordering CA2, whereas LEC innervates only the distal part, bordering subiculum, we asked if Spatial tuning is graded along the transverse axis of CA1. Tetrodes were implanted along the entire proximodistal axis of dorsal CA1 in rats. Data were recorded in cylinders large enough to elicit firing at more than one location in many neurons. Distal CA1 cells showed more dispersed firing and had a larger number of firing fields than proximal cells. Phase-locking of spikes to MEC theta oscillations was weaker in distal CA1 than in proximal CA1. The findings suggest that Spatial firing in CA1 is organized transversally, with the strongest Spatial modulation occurring in the MEC-associated proximal part.
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development of the Spatial Representation system in the rat
Science, 2010Co-Authors: Rosamund F Langston, Edvard I. Moser, Menno P. Witter, James A Ainge, Jonathan J Couey, Cathrin B Canto, Tale Litlere Bjerknes, May-britt MoserAbstract:In the adult brain, space and orientation are represented by an elaborate hippocampal-parahippocampal circuit consisting of head-direction cells, place cells, and grid cells. We report that a rudimentary map of space is already present when 2½-week-old rat pups explore an open environment outside the nest for the first time. Head-direction cells in the pre- and parasubiculum have adultlike properties from the beginning. Place and grid cells are also present but evolve more gradually. Grid cells show the slowest development. The gradual refinement of the Spatial Representation is accompanied by an increase in network synchrony among entorhinal stellate cells. The presence of adultlike directional signals at the onset of navigation raises the possibility that such signals are instrumental in setting up networks for place and grid Representation.
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finite scale of Spatial Representation in the hippocampus
Science, 2008Co-Authors: Kirsten Brun Kjelstrup, Edvard I. Moser, Menno P. Witter, Trygve Solstad, Vegard Heimly Brun, Torkel Hafting, Stefan Leutgeb, May-britt MoserAbstract:To determine how Spatial scale is represented in the pyramidal cell population of the hippocampus, we recorded neural activity at multiple longitudinal levels of this brain area while rats ran back and forth on an 18-meter-long linear track. CA3 cells had well-defined place fields at all levels. The scale of Representation increased almost linearly from <1 meter at the dorsal pole to ∼10 meters at the ventral pole. The results suggest that the place-cell map includes the entire hippocampus and that environments are represented in the hippocampus at a topographically graded but finite continuum of scales.
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impaired Spatial Representation in ca1 after lesion of direct input from entorhinal cortex
Neuron, 2008Co-Authors: Vegard Heimly Brun, Edvard I. Moser, Menno P. Witter, Stefan Leutgeb, Robert Schwarcz, May-britt MoserAbstract:Place-specific firing in the hippocampus is determined by path integration-based Spatial Representations in the grid-cell network of the medial entorhinal cortex. Output from this network is conveyed directly to CA1 of the hippocampus by projections from principal neurons in layer III, but also indirectly by axons from layer II to the dentate gyrus and CA3. The direct pathway is sufficient for Spatial firing in CA1, but it is not known whether similar firing can also be supported by the input from CA3. To test this possibility, we made selective lesions in layer III of medial entorhinal cortex by local infusion of the neurotoxin gamma-acetylenic GABA. Firing fields in CA1 became larger and more dispersed after cell loss in layer III, whereas CA3 cells, which receive layer II input, still had sharp firing fields. Thus, the direct projection is necessary for precise Spatial firing in the CA1 place cell population.
Menno P. Witter - One of the best experts on this subject based on the ideXlab platform.
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Spatial Representation along the proximodistal axis of ca1
Neuron, 2010Co-Authors: Espen J Henriksen, May-britt Moser, Menno P. Witter, Laura Lee Colgin, Carol A Barnes, Edvard I. MoserAbstract:CA1 cells receive direct input from space-responsive cells in medial entorhinal cortex (MEC), such as grid cells, as well as more nonSpatial cells in lateral entorhinal cortex (LEC). Because MEC projects preferentially to the proximal part of the CA1, bordering CA2, whereas LEC innervates only the distal part, bordering subiculum, we asked if Spatial tuning is graded along the transverse axis of CA1. Tetrodes were implanted along the entire proximodistal axis of dorsal CA1 in rats. Data were recorded in cylinders large enough to elicit firing at more than one location in many neurons. Distal CA1 cells showed more dispersed firing and had a larger number of firing fields than proximal cells. Phase-locking of spikes to MEC theta oscillations was weaker in distal CA1 than in proximal CA1. The findings suggest that Spatial firing in CA1 is organized transversally, with the strongest Spatial modulation occurring in the MEC-associated proximal part.
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development of the Spatial Representation system in the rat
Science, 2010Co-Authors: Rosamund F Langston, Edvard I. Moser, Menno P. Witter, James A Ainge, Jonathan J Couey, Cathrin B Canto, Tale Litlere Bjerknes, May-britt MoserAbstract:In the adult brain, space and orientation are represented by an elaborate hippocampal-parahippocampal circuit consisting of head-direction cells, place cells, and grid cells. We report that a rudimentary map of space is already present when 2½-week-old rat pups explore an open environment outside the nest for the first time. Head-direction cells in the pre- and parasubiculum have adultlike properties from the beginning. Place and grid cells are also present but evolve more gradually. Grid cells show the slowest development. The gradual refinement of the Spatial Representation is accompanied by an increase in network synchrony among entorhinal stellate cells. The presence of adultlike directional signals at the onset of navigation raises the possibility that such signals are instrumental in setting up networks for place and grid Representation.
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finite scale of Spatial Representation in the hippocampus
Science, 2008Co-Authors: Kirsten Brun Kjelstrup, Edvard I. Moser, Menno P. Witter, Trygve Solstad, Vegard Heimly Brun, Torkel Hafting, Stefan Leutgeb, May-britt MoserAbstract:To determine how Spatial scale is represented in the pyramidal cell population of the hippocampus, we recorded neural activity at multiple longitudinal levels of this brain area while rats ran back and forth on an 18-meter-long linear track. CA3 cells had well-defined place fields at all levels. The scale of Representation increased almost linearly from <1 meter at the dorsal pole to ∼10 meters at the ventral pole. The results suggest that the place-cell map includes the entire hippocampus and that environments are represented in the hippocampus at a topographically graded but finite continuum of scales.
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impaired Spatial Representation in ca1 after lesion of direct input from entorhinal cortex
Neuron, 2008Co-Authors: Vegard Heimly Brun, Edvard I. Moser, Menno P. Witter, Stefan Leutgeb, Robert Schwarcz, May-britt MoserAbstract:Place-specific firing in the hippocampus is determined by path integration-based Spatial Representations in the grid-cell network of the medial entorhinal cortex. Output from this network is conveyed directly to CA1 of the hippocampus by projections from principal neurons in layer III, but also indirectly by axons from layer II to the dentate gyrus and CA3. The direct pathway is sufficient for Spatial firing in CA1, but it is not known whether similar firing can also be supported by the input from CA3. To test this possibility, we made selective lesions in layer III of medial entorhinal cortex by local infusion of the neurotoxin gamma-acetylenic GABA. Firing fields in CA1 became larger and more dispersed after cell loss in layer III, whereas CA3 cells, which receive layer II input, still had sharp firing fields. Thus, the direct projection is necessary for precise Spatial firing in the CA1 place cell population.
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Spatial Representation and the architecture of the entorhinal cortex
Trends in Neurosciences, 2006Co-Authors: Menno P. Witter, Edvard I. MoserAbstract:It has recently been recognized that the entorhinal cortex has a crucial role in Spatial Representation and navigation. How the position of an animal is computed within the entorhinal circuitry remains to be determined, but the architectural organization of this brain area might provide some clues. Here, we review three organizational principles – recurrent connectivity, interlaminar connectivity and modular organization – and propose how each of them might contribute to the emergence and maintenance of positional Representations in entorhinal neural networks.
Evangelia I Zacharaki - One of the best experts on this subject based on the ideXlab platform.
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enzynet enzyme classification using 3d convolutional neural networks on Spatial Representation
PeerJ, 2018Co-Authors: Afshine Amidi, Shervine Amidi, Dimitrios Vlachakis, Vasileios Megalooikonomou, Nikos Paragios, Evangelia I ZacharakiAbstract:: During the past decade, with the significant progress of computational power as well as ever-rising data availability, deep learning techniques became increasingly popular due to their excellent performance on computer vision problems. The size of the Protein Data Bank (PDB) has increased more than 15-fold since 1999, which enabled the expansion of models that aim at predicting enzymatic function via their amino acid composition. Amino acid sequence, however, is less conserved in nature than protein structure and therefore considered a less reliable predictor of protein function. This paper presents EnzyNet, a novel 3D convolutional neural networks classifier that predicts the Enzyme Commission number of enzymes based only on their voxel-based Spatial structure. The Spatial distribution of biochemical properties was also examined as complementary information. The two-layer architecture was investigated on a large dataset of 63,558 enzymes from the PDB and achieved an accuracy of 78.4% by exploiting only the binary Representation of the protein shape. Code and datasets are available at https://github.com/shervinea/enzynet.
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enzynet enzyme classification using 3d convolutional neural networks on Spatial Representation
arXiv: Quantitative Methods, 2017Co-Authors: Afshine Amidi, Shervine Amidi, Dimitrios Vlachakis, Vasileios Megalooikonomou, Nikos Paragios, Evangelia I ZacharakiAbstract:During the past decade, with the significant progress of computational power as well as ever-rising data availability, deep learning techniques became increasingly popular due to their excellent performance on computer vision problems. The size of the Protein Data Bank has increased more than 15 fold since 1999, which enabled the expansion of models that aim at predicting enzymatic function via their amino acid composition. Amino acid sequence however is less conserved in nature than protein structure and therefore considered a less reliable predictor of protein function. This paper presents EnzyNet, a novel 3D-convolutional neural networks classifier that predicts the Enzyme Commission number of enzymes based only on their voxel-based Spatial structure. The Spatial distribution of biochemical properties was also examined as complementary information. The 2-layer architecture was investigated on a large dataset of 63,558 enzymes from the Protein Data Bank and achieved an accuracy of 78.4% by exploiting only the binary Representation of the protein shape. Code and datasets are available at this https URL.
Justin T Maxwell - One of the best experts on this subject based on the ideXlab platform.
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sampling density and date along with species selection influence Spatial Representation of tree ring reconstructions
Climate of The Past, 2020Co-Authors: Justin T Maxwell, Grant L Harley, Trevis J Matheus, Brandon M Strange, Kayla Van Aken, Joshua C BregyAbstract:Abstract. Our understanding of the natural variability of hydroclimate before the instrumental period (ca. 1900 CE in the United States) is largely dependent on tree-ring-based reconstructions. Large-scale soil moisture reconstructions from a network of tree-ring chronologies have greatly improved our understanding of the Spatial and temporal variability in hydroclimate conditions, particularly extremes of both drought and pluvial (wet) events. However, certain regions within these large-scale network reconstructions in the US are modeled by few tree-ring chronologies. Further, many of the chronologies currently publicly available on the International Tree-Ring Data Bank (ITRDB) were collected in the 1980s and 1990s, and thus our understanding of the sensitivity of radial growth to soil moisture in the US is based on a period that experienced multiple extremely severe droughts and neglects the impacts of recent, rapid global change. In this study, we expanded the tree-ring network of the Ohio River valley in the US, a region with sparse coverage. We used a total of 72 chronologies across 15 species to examine how increasing the density of the tree-ring network influences the Representation of reconstructing the Palmer Meteorological Drought Index (PMDI). Further, we tested how the sampling date and therefore the calibration period influenced the reconstruction models by creating reconstructions that ended in the year 1980 and compared them to reconstructions ending in 2010 from the same chronologies. We found that increasing the density of the tree-ring network resulted in reconstructed values that better matched the Spatial variability of instrumentally recorded droughts and, to a lesser extent, pluvials. By extending the calibration period to 2010 compared to 1980, the sensitivity of tree rings to PMDI decreased in the southern portion of our region where severe drought conditions have been absent over recent decades. We emphasize the need of building a high-density tree-ring network to better represent the Spatial variability of past droughts and pluvials. Further, chronologies on the ITRDB need updating regularly to better understand how the sensitivity of tree rings to climate may vary through time.
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sampling density and date influence Spatial Representation of tree ring reconstructions
Climate of The Past Discussions, 2020Co-Authors: Justin T Maxwell, Grant L Harley, Trevis J Matheus, Brandon M Strange, Kayla Van Aken, Tsun Fung Au, Joshua C BregyAbstract:Abstract. Our understanding of the natural variability of hydroclimate before the instrumental period (ca. 1900 in the United States; US) is largely dependent on tree-ring-based reconstructions. Large-scale soil moisture reconstructions from a network of tree-ring chronologies have greatly improved our understanding of the Spatial and temporal variability in hydroclimate conditions, particularly extremes of both drought and pluvial (wet) events. However, certain regions within these large-scale reconstructions in the US have a sparse network of tree-ring chronologies. Further, several chronologies were collected in the 1980s and 1990s, thus our understanding of the sensitivity of radial growth to soil moisture in the US is based on a period that experienced multiple extremely severe droughts and neglects the impacts of recent, rapid global change. In this study, we expanded the tree-ring network of the Ohio River Valley in the US, a region with sparse coverage. We used a total of 72 chronologies across 15 species to examine how increasing the density of the tree-ring network influences the Representation of reconstructing the Palmer Meteorological Drought Index (PMDI). Further, we tested how the sampling date influenced the reconstruction models by creating reconstructions that ended in the year 1980 and compared them to reconstructions ending in 2010 from the same chronologies. We found that increasing the density of the tree-ring network resulted in reconstructed values that better matched the Spatial variability of instrumentally recorded droughts and to a lesser extent, pluvials. By sampling tree in 2010 compared to 1980, the sensitivity of tree rings to PMDI decreased in the southern portion of our region where severe drought conditions have been absent over recent decades. We emphasize the need of building a high-density tree-ring network to better represent the Spatial variability of past droughts and pluvials. Further, chronologies on the International Tree-Ring Data Bank need updating regularly to better understand how the sensitivity of tree rings to climate may vary through time.
