The Experts below are selected from a list of 16101 Experts worldwide ranked by ideXlab platform
Guy N. Elston - One of the best experts on this subject based on the ideXlab platform.
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Regional Specialization in pyramidal cell structure in the limbic cortex of the vervet monkey (Cercopithecus pygerythrus): an intracellular injection study of the anterior and posterior cingulate gyrus
Experimental Brain Research, 2005Co-Authors: Guy N. Elston, Ruth Benavides-piccione, Alejandra Elston, Paul R Manger, Javier DefelipeAbstract:The pyramidal cell phenotype varies quite dramatically in structure among different cortical areas in the primate brain. Comparative studies in visual cortex, in particular, but also in sensorimotor and prefrontal cortex, reveal systematic trends for pyramidal cell Specialization in functionally related cortical areas. Moreover, there are systematic differences in the extent of these trends between different primate species. Recently we demonstrated differences in pyramidal cell structure in the cingulate cortex of the macaque monkey; however, in the absence of other comparative data it remains unknown as to whether the neuronal phenotype differs in cingulate cortex between species. Here we extend the basis for comparison by studying the structure of the basal dendritic trees of layer III pyramidal cells in the posterior and anterior cingulate gyrus of the vervet monkey (Brodmann’s areas 23 and 24, respectively). Cells were injected with Lucifer Yellow in flat-mounted cortical slices, and processed for a light-stable DAB reaction product. Size, branching pattern, and spine density of basal dendritic arbors were determined, and somal areas measured. As in the macaque monkey, we found that pyramidal cells in anterior cingulate gyrus (area 24) were more branched and more spinous than those in posterior cingulate gyrus (area 23). In addition, the extent of the difference in pyramidal cell structure between these two cortical regions was less in the vervet monkey than in the macaque monkey.
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Regional Specialization in pyramidal cell structure in the visual cortex of the galago an intracellular injection study of striate and extrastriate areas with comparative notes on new world and old world monkeys
Brain Behavior and Evolution, 2005Co-Authors: Guy N. Elston, Alejandra Elston, Jon H Kaas, Vivien A CasagrandeAbstract:Recent studies have revealed marked differences in the basal dendritic structure of layer III pyramidal cells in the cerebral cortex of adult simian primates. In particular, there is a consistent trend for pyramidal cells of increasing complexity with anterior progression through occipitotemporal cortical visual areas. These differences in pyramidal cell structure, and their systematic nature, are believed to be important for specialized aspects of visual processing within, and between, cortical areas. However, it remains unknown whether this Regional Specialization in the pyramidal cell phenotype is unique to simians, is unique to primates in general or is widespread amongst mammalian species. In the present study we investigated pyramidal cell structure in the prosimian galago (Otolemur garnetti). We found, as in simians, that the basal dendritic arbors of pyramidal cells differed between cortical areas. More specifically, pyramidal cells became progressively more spinous through the primary (V1), second (V2), dorsolateral (DL) and inferotemporal (IT) visual areas. Moreover, pyramidal neurons in V1 of the galago are remarkably similar to those in other primate species, in spite of large differences in the sizes of this area. In contrast, pyramidal cells in inferotemporal cortex are quite variable among primate species. These data suggest that Regional Specialization in pyramidal cell phenotype was a likely feature of cortex in a common ancestor of simian and prosimian primates, but the degree of Specialization varies between species.
G W Arbuthnott - One of the best experts on this subject based on the ideXlab platform.
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striatal contributions to reward and decision making making sense of Regional variations in a reiterated processing matrix
Annals of the New York Academy of Sciences, 2007Co-Authors: Jeffery R Wickens, Christopher S Budd, Brian I Hyland, G W ArbuthnottAbstract:The striatum is the major input nucleus of the basal ganglia. It is thought to play a key role in learning on the basis of positive reinforcement and in action selection. One view of the striatum conceives it as comprising a reiterated matrix of processing units that perform common operations in different striatal regions, namely synaptic plasticity according to a three-factor rule, and lateral inhibition. These operations are required for reinforcement learning and selection of previously reinforced actions. Analysis of the behavioral effects of circumscribed lesions of the striatum, however, suggests Regional Specialization of learning and decision-making operations. We consider how a basic processing unit may be modified by Regional variations in neurochemical parameters, for example, by the gradient in density of dopamine terminals from dorsal to ventral striatum. These variations suggest subtle differences between dorsolateral and ventromedial striatal regions in the temporal properties of dopamine signaling, which are superimposed on Regional differences in connectivity. We propose that these variations make sense in relation to the temporal structure of activity in striatal inputs from different regions, and the requirements of different learning operations. Dorsolateral striatal (DLS) regions may be subject to brief, precisely timed pulses of dopamine, whereas ventromedial striatal regions integrate dopamine signals over a longer time course. These differences may be important for understanding Regional variations in the contribution to reinforcement of habits, versus incentive processes that are sensitive to the value of expected rewards.
Igor Vodyanoy - One of the best experts on this subject based on the ideXlab platform.
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functional localization of single active ion channels on the surface of a living cell
Nature Cell Biology, 2000Co-Authors: Yuri E Korchev, Yuri A Negulyaev, Christopher R W Edwards, Igor VodyanoyAbstract:The spatial distribution of ion channels in the cell plasma membrane has an important role in governing Regional Specialization, providing a precise and localized control over cell function. We report here a novel technique based on scanning ion conductance microscopy that allows, for the first time, mapping of single active ion channels in intact cell plasma membranes. We have mapped the distribution of ATP-regulated K+ channels (KATP channels) in cardiac myocytes. The channels are organized in small groups and anchored in the Z-grooves of the sarcolemma. The distinct pattern of distribution of these channels may have important functional implications.
Javier Defelipe - One of the best experts on this subject based on the ideXlab platform.
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voltage gated ion channels in the axon initial segment of human cortical pyramidal cells and their relationship with chandelier cells
Proceedings of the National Academy of Sciences of the United States of America, 2006Co-Authors: Maria Carmen Inda, Javier Defelipe, Alberto MunozAbstract:The axon initial segment (AIS) of pyramidal cells is a critical region for the generation of action potentials and for the control of pyramidal cell activity. Here we show that Na+ and K+ voltage-gated channels, together with other molecules involved in the localization of ion channels, are distributed asymmetrically in the AIS of pyramidal cells situated in the human temporal neocortex. There is a high density of Na+ channels distributed along the length of the AIS together with the associated proteins spectrin βIV and ankyrin G. In contrast, Kv1.2 channels are associated with the adhesion molecule Caspr2, and they are mostly localized to the distal region of the AIS. In general, the distal region of the AIS is targeted by the GABAergic axon terminals of chandelier cells, whereas the proximal region is innervated, mostly by other types of GABAergic interneurons. We suggest that this molecular segregation and the consequent Regional Specialization of the GABAergic input to the AIS of pyramidal cells may have important functional implications for the control of pyramidal cell activity.
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Regional Specialization in pyramidal cell structure in the limbic cortex of the vervet monkey (Cercopithecus pygerythrus): an intracellular injection study of the anterior and posterior cingulate gyrus
Experimental Brain Research, 2005Co-Authors: Guy N. Elston, Ruth Benavides-piccione, Alejandra Elston, Paul R Manger, Javier DefelipeAbstract:The pyramidal cell phenotype varies quite dramatically in structure among different cortical areas in the primate brain. Comparative studies in visual cortex, in particular, but also in sensorimotor and prefrontal cortex, reveal systematic trends for pyramidal cell Specialization in functionally related cortical areas. Moreover, there are systematic differences in the extent of these trends between different primate species. Recently we demonstrated differences in pyramidal cell structure in the cingulate cortex of the macaque monkey; however, in the absence of other comparative data it remains unknown as to whether the neuronal phenotype differs in cingulate cortex between species. Here we extend the basis for comparison by studying the structure of the basal dendritic trees of layer III pyramidal cells in the posterior and anterior cingulate gyrus of the vervet monkey (Brodmann’s areas 23 and 24, respectively). Cells were injected with Lucifer Yellow in flat-mounted cortical slices, and processed for a light-stable DAB reaction product. Size, branching pattern, and spine density of basal dendritic arbors were determined, and somal areas measured. As in the macaque monkey, we found that pyramidal cells in anterior cingulate gyrus (area 24) were more branched and more spinous than those in posterior cingulate gyrus (area 23). In addition, the extent of the difference in pyramidal cell structure between these two cortical regions was less in the vervet monkey than in the macaque monkey.
Walter W Powell - One of the best experts on this subject based on the ideXlab platform.
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a comparison of u s and european university industry relations in the life sciences
Management Science, 2002Co-Authors: Jason Owensmith, Massimo Riccaboni, Fabio Pammolli, Walter W PowellAbstract:We draw on diverse data sets to compare the institutional organization of upstream life science research across the United States and Europe. Understanding cross-national differences in the organization of innovative labor in the life sciences requires attention to the structure and evolution of biomedical networks involving public research organizations (universities, government laboratories, nonprofit research institutes, and research hospitals), science-based biotechnology firms, and multinational pharmaceutical corporations. We use network visualization methods and correspondence analyses to demonstrate that innovative research in biomedicine has its origins in Regional clusters in the United States and in European nations. But the scientific and organizational composition of these regions varies in consequential ways. In the United States, public research organizations and small firms conduct R&D across multiple therapeutic areas and stages of the development process. Ties within and across these regions link small firms and diverse public institutions, contributing to the development of a robust national network. In contrast, the European story is one of Regional Specialization with a less diverse group of public research organizations working in a smaller number of therapeutic areas. European institutes develop local connections to small firms working on similar scientific problems, while cross-national linkages of European Regional clusters typically involve large pharmaceutical corporations. We show that the roles of large and small firms differ in the United States and Europe, arguing that the greater heterogeneity of the U.S. system is based on much closer integration of basic science and clinical development.
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a comparison of u s and european university industry relations in the life sciences
LEM Papers Series, 2001Co-Authors: Jason Owensmith, Massimo Riccaboni, Fabio Pammolli, Walter W PowellAbstract:We draw on diverse data sets to compare the institutional organization of upstream life science research across the United States and Europe. Understanding cross-national differences in the organization of innovative labor in the life sciences requires attention to the structure and evolution of biomedical networks involving public research organizations (universities, government laboratories, nonprofit research institutes, and research hospitals), science-based biotechnology firms, and multinational pharmaceutical corporations. We use network visualization methods and correspondence analyses to demonstrate that innovative research in biomedicine has its origins in Regional clusters in the United States and in European nations. But the scientific and organizational composition of these regions varies in consequential ways. In the United States, public research organizations and small firms conduct R&D across multiple therapeutic areas and stages of the development process. Ties within and across these regions link small firms and diverse public institutions, contributing to the development of a robust national network. In contrast, the European story is one of Regional Specialization with a less diverse group of public research organizations working in a smaller number of therapeutic areas. European institutes develop local connections to small firms working on similar scientific problems, while cross-national linkages of European Regional clusters typically involve large pharmaceutical corporations. We show that the roles of large and small firms differ in the United States and Europe, arguing that the greater heterogeneity of the U.S. system is based on much closer integration of basic science and clinical development.(This abstract was borrowed from another version of this item.)
