The Experts below are selected from a list of 194427 Experts worldwide ranked by ideXlab platform
D Pal - One of the best experts on this subject based on the ideXlab platform.
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A study of subgrain formation in Al 3003 H-18 foils undergoing ultrasonic additive manufacturing using a dislocation density based crystal plasticity finite element framework
Journal of Applied Physics, 2013Co-Authors: D PalAbstract:A novel dislocation density based crystal plasticity finite element model (DDCP-FEM) framework has been extended to predict subgrain formation during ultrasonic additive manufacturing of Al 3003 H-18 tempered foils. The present study identifies various microstructural transitions such as recrystallization and dislocation density evolutions that occur during the Processing of these foils as a function of Input Processing parameters such as normal force, ultrasonic oscillation amplitude, and initial microstructure. Furthermore, changes in average grain sizes in the Al 3003 H-18 foils have been calculated before and after Processing from both microstructures and the simulation study. The simulation predictions were in good agreement with experimental results. This provides evidence that DDCP-FEM can be used as a tool for optimizing Input Processing parameters so that minimal grain fragmentation occurs during Processing leading to better mechanical properties for 3 dimensional components made using ultrasonic additive manufacturing. (C) 2013 AIP Publishing LLC.
Brent Stucker - One of the best experts on this subject based on the ideXlab platform.
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a study of subgrain formation in al 3003 h 18 foils undergoing ultrasonic additive manufacturing using a dislocation density based crystal plasticity finite element framework
Journal of Applied Physics, 2013Co-Authors: Brent StuckerAbstract:A novel dislocation density based crystal plasticity finite element model (DDCP-FEM) framework has been extended to predict subgrain formation during ultrasonic additive manufacturing of Al 3003 H-18 tempered foils. The present study identifies various microstructural transitions such as recrystallization and dislocation density evolutions that occur during the Processing of these foils as a function of Input Processing parameters such as normal force, ultrasonic oscillation amplitude, and initial microstructure. Furthermore, changes in average grain sizes in the Al 3003 H-18 foils have been calculated before and after Processing from both microstructures and the simulation study. The simulation predictions were in good agreement with experimental results. This provides evidence that DDCP-FEM can be used as a tool for optimizing Input Processing parameters so that minimal grain fragmentation occurs during Processing leading to better mechanical properties for 3 dimensional components made using ultrasonic...
Allen F. Mensinger - One of the best experts on this subject based on the ideXlab platform.
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potential role of the anterior lateral line in sound localization in toadfish opsanus tau
The Journal of Experimental Biology, 2018Co-Authors: Allen F. Mensinger, Emily A Cardinal, Craig A RadfordAbstract:Male oyster toadfish (Opsanus tau) acoustically attract females to nesting sites using a boatwhistle call. The rapid speed of sound underwater combined with the close proximity of the otolithic organs makes inner ear interaural time differences an unlikely mechanism to localize sound. To determine the role that the mechanosensory lateral line may play in sound localization, microwire electrodes were bilaterally implanted into the anterior lateral line nerve to record neural responses to vibrational stimuli. Highest spike rates and strongest phase-locking occurred at distances close to the fish and decreased as the stimulus was moved further from the fish. Bilateral anterior lateral line neuromasts displayed differential directional sensitivity to incoming vibrational stimuli, which suggests the potential for the lateral line to be used for sound localization in the near field. The present study also demonstrates that the spatially separated neuromasts of the toadfish may provide sufficient time delays between sensory organs for determining sound localization cues. Multimodal sensory Input Processing through both the inner ear (far field) and lateral line (near field) may allow for effective sound localization in fish.
Dietmar Plenz - One of the best experts on this subject based on the ideXlab platform.
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neuronal avalanches imply maximum dynamic range in cortical networks at criticality
The Journal of Neuroscience, 2009Co-Authors: Woodrow L Shew, Thomas Petermann, Hongdian Yang, Rajarshi Roy, Dietmar PlenzAbstract:Spontaneous neuronal activity is a ubiquitous feature of cortex. Its spatiotemporal organization reflects past Input and modulates future network output. Here we study whether a particular type of spontaneous activity is generated by a network that is optimized for Input Processing. Neuronal avalanches are a type of spontaneous activity observed in superficial cortical layers in vitro and in vivo with statistical properties expected from a network operating at “criticality.” Theory predicts that criticality and, therefore, neuronal avalanches are optimal for Input Processing, but until now, this has not been tested in experiments. Here, we use cortex slice cultures grown on planar microelectrode arrays to demonstrate that cortical networks that generate neuronal avalanches benefit from a maximized dynamic range, i.e., the ability to respond to the greatest range of stimuli. By changing the ratio of excitation and inhibition in the cultures, we derive a network tuning curve for stimulus Processing as a function of distance from criticality in agreement with predictions from our simulations. Our findings suggest that in the cortex, (1) balanced excitation and inhibition establishes criticality, which maximizes the range of Inputs that can be processed, and (2) spontaneous activity and Input Processing are unified in the context of critical phenomena.
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spontaneous cortical activity in awake monkeys composed of neuronal avalanches
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Thomas Petermann, Mikhail A Lebedev, Miguel A L Nicolelis, Tara C Thiagarajan, Dante R Chialvo, Dietmar PlenzAbstract:Spontaneous neuronal activity is an important property of the cerebral cortex but its spatiotemporal organization and dynamical framework remain poorly understood. Studies in reduced systems—tissue cultures, acute slices, and anesthetized rats—show that spontaneous activity forms characteristic clusters in space and time, called neuronal avalanches. Modeling studies suggest that networks with this property are poised at a critical state that optimizes Input Processing, information storage, and transfer, but the relevance of avalanches for fully functional cerebral systems has been controversial. Here we show that ongoing cortical synchronization in awake rhesus monkeys carries the signature of neuronal avalanches. Negative LFP deflections (nLFPs) correlate with neuronal spiking and increase in amplitude with increases in local population spike rate and synchrony. These nLFPs form neuronal avalanches that are scale-invariant in space and time and with respect to the threshold of nLFP detection. This dimension, threshold invariance, describes a fractal organization: smaller nLFPs are embedded in clusters of larger ones without destroying the spatial and temporal scale-invariance of the dynamics. These findings suggest an organization of ongoing cortical synchronization that is scale-invariant in its three fundamental dimensions—time, space, and local neuronal group size. Such scale-invariance has ontogenetic and phylogenetic implications because it allows large increases in network capacity without a fundamental reorganization of the system.
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neuronal avalanches imply maximum dynamic range in cortical networks at criticality
arXiv: Neurons and Cognition, 2009Co-Authors: Woodrow L Shew, Thomas Petermann, Hongdian Yang, Rajarshi Roy, Dietmar PlenzAbstract:Spontaneous neuronal activity is a ubiquitous feature of cortex. Its spatiotemporal organization reflects past Input and modulates future network output. Here we study whether a particular type of spontaneous activity is generated by a network that is optimized for Input Processing. Neuronal avalanches are a type of spontaneous activity observed in superficial cortical layers in vitro and in vivo with statistical properties expected from a network in a 'critical state'. Theory predicts that the critical state and, therefore, neuronal avalanches are optimal for Input Processing, but until now, this is untested in experiments. Here, we use cortex slice cultures grown on planar microelectrode arrays to demonstrate that cortical networks which generate neuronal avalanches benefit from maximized dynamic range, i.e. the ability to respond to the greatest range of stimuli. By changing the ratio of excitation and inhibition in the cultures, we derive a network tuning curve for stimulus Processing as a function of distance from the critical state in agreement with predictions from our simulations. Our findings suggest that in the cortex, (1) balanced excitation and inhibition establishes the critical state, which maximizes the range of Inputs that can be processed and (2) spontaneous activity and Input Processing are unified in the context of critical phenomena.
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when inhibition goes incognito feedback interaction between spiny projection neurons in striatal function
Trends in Neurosciences, 2003Co-Authors: Dietmar PlenzAbstract:Theories about basal ganglia function have always been driven by our knowledge about the spiny projection neurons of the striatum. At the core of these theories lies the question of how, precisely, spiny projection neurons process cortical Inputs. Most recently, studies demonstrating the role of spiny projection neurons in local synaptic GABA transmission have provided several new avenues for exploring striatal dynamics. They have also suggested new experimental directives for examining the specific ways in which spiny projection neurons both compete and cooperate through their local axon collaterals during cortical Input Processing.
Emily A Cardinal - One of the best experts on this subject based on the ideXlab platform.
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potential role of the anterior lateral line in sound localization in toadfish opsanus tau
The Journal of Experimental Biology, 2018Co-Authors: Allen F. Mensinger, Emily A Cardinal, Craig A RadfordAbstract:Male oyster toadfish (Opsanus tau) acoustically attract females to nesting sites using a boatwhistle call. The rapid speed of sound underwater combined with the close proximity of the otolithic organs makes inner ear interaural time differences an unlikely mechanism to localize sound. To determine the role that the mechanosensory lateral line may play in sound localization, microwire electrodes were bilaterally implanted into the anterior lateral line nerve to record neural responses to vibrational stimuli. Highest spike rates and strongest phase-locking occurred at distances close to the fish and decreased as the stimulus was moved further from the fish. Bilateral anterior lateral line neuromasts displayed differential directional sensitivity to incoming vibrational stimuli, which suggests the potential for the lateral line to be used for sound localization in the near field. The present study also demonstrates that the spatially separated neuromasts of the toadfish may provide sufficient time delays between sensory organs for determining sound localization cues. Multimodal sensory Input Processing through both the inner ear (far field) and lateral line (near field) may allow for effective sound localization in fish.