The Experts below are selected from a list of 170235 Experts worldwide ranked by ideXlab platform
Iris Grothe - One of the best experts on this subject based on the ideXlab platform.
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attention selectively gates afferent Signal Transmission to area v4
The Journal of Neuroscience, 2018Co-Authors: Iris Grothe, David Rotermund, Simon D Neitzel, Sunita Mandon, Udo Ernst, Andreas K Kreiter, Klaus PawelzikAbstract:Selective attention allows focusing on only part of the incoming sensory information. Neurons in the extrastriate visual cortex reflect such selective processing when different stimuli are simultaneously present in their large receptive fields. Their spiking response then resembles the response to the attended stimulus when presented in isolation. Unclear is where in the neuronal pathway attention intervenes to achieve such selective Signal routing and processing. To investigate this question, we tagged two equivalent visual stimuli by independent broadband luminance noise and used the spectral coherence of these behaviorally irrelevant Signals with the field potential of a local neuronal population in male macaque monkeys9 area V4 as a measure for their respective causal influences. This new experimental paradigm revealed that Signal Transmission was considerably weaker for the not-attended stimulus. Furthermore, our results show that attention does not need to modulate responses in the input populations sending Signals to V4 to selectively represent a stimulus, nor do they suggest a change of the V4 neurons9 output gain depending on their feature similarity with the stimuli. Our results rather imply that selective attention uses a gating mechanism comprising the synaptic “inputs” that transmit Signals from upstream areas into the V4 neurons. A minimal model implementing attention-dependent routing by gamma-band synchrony replicated the attentional gating effect and the Signals9 spectral transfer characteristics. It supports the proposal that selective interareal gamma-band synchrony subserves Signal routing and explains our experimental finding that attention selectively gates Signals already at the level of afferent synaptic input. SIGNIFICANCE STATEMENT Depending on the behavioral context, the brain needs to channel the flow of information through its networks of massively interconnected neurons. We designed an experiment that allows to causally assess routing of information originating from an attended object. We found that attention “gates” Signals at the interplay between afferent fibers and the local neurons. A minimal model demonstrated that coherent gamma-rhythmic activity (∼60 Hz) between local neurons and their afferent-providing input neurons can realize the gating. Importantly, the attended Signals did not need to be amplified already in an earlier processing stage, nor did they get amplified by a simple output response modulation. The method provides a useful tool to study mechanisms of dynamic network configuration underlying cognitive processes.
Klaus Pawelzik - One of the best experts on this subject based on the ideXlab platform.
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attention selectively gates afferent Signal Transmission to area v4
The Journal of Neuroscience, 2018Co-Authors: Iris Grothe, David Rotermund, Simon D Neitzel, Sunita Mandon, Udo Ernst, Andreas K Kreiter, Klaus PawelzikAbstract:Selective attention allows focusing on only part of the incoming sensory information. Neurons in the extrastriate visual cortex reflect such selective processing when different stimuli are simultaneously present in their large receptive fields. Their spiking response then resembles the response to the attended stimulus when presented in isolation. Unclear is where in the neuronal pathway attention intervenes to achieve such selective Signal routing and processing. To investigate this question, we tagged two equivalent visual stimuli by independent broadband luminance noise and used the spectral coherence of these behaviorally irrelevant Signals with the field potential of a local neuronal population in male macaque monkeys9 area V4 as a measure for their respective causal influences. This new experimental paradigm revealed that Signal Transmission was considerably weaker for the not-attended stimulus. Furthermore, our results show that attention does not need to modulate responses in the input populations sending Signals to V4 to selectively represent a stimulus, nor do they suggest a change of the V4 neurons9 output gain depending on their feature similarity with the stimuli. Our results rather imply that selective attention uses a gating mechanism comprising the synaptic “inputs” that transmit Signals from upstream areas into the V4 neurons. A minimal model implementing attention-dependent routing by gamma-band synchrony replicated the attentional gating effect and the Signals9 spectral transfer characteristics. It supports the proposal that selective interareal gamma-band synchrony subserves Signal routing and explains our experimental finding that attention selectively gates Signals already at the level of afferent synaptic input. SIGNIFICANCE STATEMENT Depending on the behavioral context, the brain needs to channel the flow of information through its networks of massively interconnected neurons. We designed an experiment that allows to causally assess routing of information originating from an attended object. We found that attention “gates” Signals at the interplay between afferent fibers and the local neurons. A minimal model demonstrated that coherent gamma-rhythmic activity (∼60 Hz) between local neurons and their afferent-providing input neurons can realize the gating. Importantly, the attended Signals did not need to be amplified already in an earlier processing stage, nor did they get amplified by a simple output response modulation. The method provides a useful tool to study mechanisms of dynamic network configuration underlying cognitive processes.
Yoon Jung Park - One of the best experts on this subject based on the ideXlab platform.
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polymer based long range surface plasmon polariton waveguides for 10 gbps optical Signal Transmission applications
Journal of Lightwave Technology, 2008Co-Authors: Suntak Park, Seung Koo Park, Yoon Jung Park, Minsu Kim, Jin Tae Kim, Myunghyun LeeAbstract:We present characteristics of very thin Au strip waveguides based on long-range surface plasmon polaritons (LR-SPPs) along thin Au strips embedded in polymers. We also report a 10 Gbps optical Signal Transmission via LR-SPPs with the pig-tailed Au strip waveguide at a telecommunication wavelength of 1.55 mum. We limited the thickness, width, and length up to ~20 nm, ~ 10 mum, and ~5 cm, respectively, for practical applications. At 1.55 mum, loss properties of the Au strip waveguides were theoretically and experimentally evaluated with thickness, width and cladding material. The lowest propagation loss of ~1.4 dB/cm was experimentally obtained with the 14-nm-thick and 2-mum-wide Au strip. With a single-mode fiber, the lowest coupling loss of less than 0.1 dB/facet was achieved with the 14-nm-thick and 7.5-mum-wide Au strip. The lowest insertion loss was obtained 7.7 dB with the 14-nm-thick, 5-mum-wide, and 1.5-cm-long Au strip. The propagation loss was improved approximately 30% for the 17-nm-thick Au strip with lowering the refractive index of the cladding polymer by 0.01. In the 10 Gbps optical Signal Transmission experiment, the LR-SPP waveguide exhibits an excellent eye opening and a 2.2 dB power penalty at 10-12 bit error rate. These all results indicate that the LR-SPP waveguide is a potential Transmission line for optical interconnects to overcome inherent problems in electric interconnects.
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40gbit s light Signal Transmission in long range surface plasmon waveguides
Applied Physics Letters, 2007Co-Authors: Jung Jin Ju, Suntak Park, Seung Koo Park, Yoon Jung ParkAbstract:We demonstrate a high bit-rate optical Signal Transmission by using long-range surface plasmon polariton (LRSPP) waves in a guided geometry. With a 40Gbit∕s optical communication Signal, eye patterns and bit-error-rates were measured to access the quality of the Transmission properties of the LRSPP mode. A thin gold strip line embedded in a low loss optical polymer supports a LRSPP mode, which propagates with a 2dB∕cm loss, and couples to standard single mode fibers at 1.55μm with a 2dB coupling loss. A 40Gbit∕s optical Signal was transmitted via a 4cm long LRSPP waveguide without any distortion of the eye patterns. The experiment also showed error-free Transmissions. These results indicate that the LRSPP waveguide is a potential Transmission line for optical interconnections overcoming the inherent problems in electric interconnections.
Suntak Park - One of the best experts on this subject based on the ideXlab platform.
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polymer based long range surface plasmon polariton waveguides for 10 gbps optical Signal Transmission applications
Journal of Lightwave Technology, 2008Co-Authors: Suntak Park, Seung Koo Park, Yoon Jung Park, Minsu Kim, Jin Tae Kim, Myunghyun LeeAbstract:We present characteristics of very thin Au strip waveguides based on long-range surface plasmon polaritons (LR-SPPs) along thin Au strips embedded in polymers. We also report a 10 Gbps optical Signal Transmission via LR-SPPs with the pig-tailed Au strip waveguide at a telecommunication wavelength of 1.55 mum. We limited the thickness, width, and length up to ~20 nm, ~ 10 mum, and ~5 cm, respectively, for practical applications. At 1.55 mum, loss properties of the Au strip waveguides were theoretically and experimentally evaluated with thickness, width and cladding material. The lowest propagation loss of ~1.4 dB/cm was experimentally obtained with the 14-nm-thick and 2-mum-wide Au strip. With a single-mode fiber, the lowest coupling loss of less than 0.1 dB/facet was achieved with the 14-nm-thick and 7.5-mum-wide Au strip. The lowest insertion loss was obtained 7.7 dB with the 14-nm-thick, 5-mum-wide, and 1.5-cm-long Au strip. The propagation loss was improved approximately 30% for the 17-nm-thick Au strip with lowering the refractive index of the cladding polymer by 0.01. In the 10 Gbps optical Signal Transmission experiment, the LR-SPP waveguide exhibits an excellent eye opening and a 2.2 dB power penalty at 10-12 bit error rate. These all results indicate that the LR-SPP waveguide is a potential Transmission line for optical interconnects to overcome inherent problems in electric interconnects.
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40gbit s light Signal Transmission in long range surface plasmon waveguides
Applied Physics Letters, 2007Co-Authors: Jung Jin Ju, Suntak Park, Seung Koo Park, Yoon Jung ParkAbstract:We demonstrate a high bit-rate optical Signal Transmission by using long-range surface plasmon polariton (LRSPP) waves in a guided geometry. With a 40Gbit∕s optical communication Signal, eye patterns and bit-error-rates were measured to access the quality of the Transmission properties of the LRSPP mode. A thin gold strip line embedded in a low loss optical polymer supports a LRSPP mode, which propagates with a 2dB∕cm loss, and couples to standard single mode fibers at 1.55μm with a 2dB coupling loss. A 40Gbit∕s optical Signal was transmitted via a 4cm long LRSPP waveguide without any distortion of the eye patterns. The experiment also showed error-free Transmissions. These results indicate that the LRSPP waveguide is a potential Transmission line for optical interconnections overcoming the inherent problems in electric interconnections.
Udo Ernst - One of the best experts on this subject based on the ideXlab platform.
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attention selectively gates afferent Signal Transmission to area v4
The Journal of Neuroscience, 2018Co-Authors: Iris Grothe, David Rotermund, Simon D Neitzel, Sunita Mandon, Udo Ernst, Andreas K Kreiter, Klaus PawelzikAbstract:Selective attention allows focusing on only part of the incoming sensory information. Neurons in the extrastriate visual cortex reflect such selective processing when different stimuli are simultaneously present in their large receptive fields. Their spiking response then resembles the response to the attended stimulus when presented in isolation. Unclear is where in the neuronal pathway attention intervenes to achieve such selective Signal routing and processing. To investigate this question, we tagged two equivalent visual stimuli by independent broadband luminance noise and used the spectral coherence of these behaviorally irrelevant Signals with the field potential of a local neuronal population in male macaque monkeys9 area V4 as a measure for their respective causal influences. This new experimental paradigm revealed that Signal Transmission was considerably weaker for the not-attended stimulus. Furthermore, our results show that attention does not need to modulate responses in the input populations sending Signals to V4 to selectively represent a stimulus, nor do they suggest a change of the V4 neurons9 output gain depending on their feature similarity with the stimuli. Our results rather imply that selective attention uses a gating mechanism comprising the synaptic “inputs” that transmit Signals from upstream areas into the V4 neurons. A minimal model implementing attention-dependent routing by gamma-band synchrony replicated the attentional gating effect and the Signals9 spectral transfer characteristics. It supports the proposal that selective interareal gamma-band synchrony subserves Signal routing and explains our experimental finding that attention selectively gates Signals already at the level of afferent synaptic input. SIGNIFICANCE STATEMENT Depending on the behavioral context, the brain needs to channel the flow of information through its networks of massively interconnected neurons. We designed an experiment that allows to causally assess routing of information originating from an attended object. We found that attention “gates” Signals at the interplay between afferent fibers and the local neurons. A minimal model demonstrated that coherent gamma-rhythmic activity (∼60 Hz) between local neurons and their afferent-providing input neurons can realize the gating. Importantly, the attended Signals did not need to be amplified already in an earlier processing stage, nor did they get amplified by a simple output response modulation. The method provides a useful tool to study mechanisms of dynamic network configuration underlying cognitive processes.
