The Experts below are selected from a list of 13470 Experts worldwide ranked by ideXlab platform
Jason B. Mattingley - One of the best experts on this subject based on the ideXlab platform.
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Spatial Attention Enhances the Neural Representation of Invisible Signals Embedded in Noise
Journal of Cognitive Neuroscience, 2018Co-Authors: Cooper A. Smout, Jason B. MattingleyAbstract:Recent evidence suggests that voluntary spatial attention can affect Neural processing of visual stimuli that do not enter conscious awareness (i.e., invisible stimuli), supporting the notion that attention and awareness are dissociable processes [Wyart, V., Dehaene, S., & Tallon-Baudry, C. Early dissociation between Neural signatures of endogenous spatial attention and perceptual awareness during visual masking. Frontiers in Human Neuroscience, 6, 1–14, 2012; Watanabe, M., Cheng, K., Murayama, Y., Ueno, K., Asamizuya, T., Tanaka, K., et al. Attention but not awareness modulates the BOLD signal in the human V1 during binocular suppression. Science, 334, 829–831, 2011]. To date, however, no study has demonstrated that these effects reflect enhancement of the Neural Representation of invisible stimuli per se, as opposed to other Neural processes not specifically tied to the stimulus in question. In addition, it remains unclear whether spatial attention can modulate Neural Representations of invisible stimuli in direct competition with highly salient and visible stimuli. Here we developed a novel EEG frequency-tagging paradigm to obtain a continuous readout of human brain activity associated with visible and invisible signals embedded in dynamic noise. Participants (n = 23) detected occasional contrast changes in one of two flickering image streams on either side of fixation. Each image stream contained a visible or invisible signal embedded in every second noise image, the visibility of which was titrated and checked using a two-interval forced-choice detection task. Steady-state visual-evoked potentials were computed from EEG data at the signal and noise frequencies of interest. Cluster-based permutation analyses revealed significant Neural responses to both visible and invisible signals across posterior scalp electrodes. Control analyses revealed that these responses did not reflect a subharmonic response to noise stimuli. In line with previous findings, spatial attention increased the Neural Representation of visible signals. Crucially, spatial attention also increased the Neural Representation of invisible signals. As such, the present results replicate and extend previous studies by demonstrating that attention can modulate the Neural Representation of invisible signals that are in direct competition with highly salient masking stimuli.
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Spatial Attention Enhances the Neural Representation of Invisible Signals Embedded in Noise
bioRxiv, 2017Co-Authors: Cooper A. Smout, Jason B. MattingleyAbstract:Recent evidence suggests that voluntary spatial attention can modulate Neural Representations of visual stimuli that do not enter conscious awareness (i.e. invisible stimuli), supporting the notion that attention and awareness are dissociable processes (Watanabe et al., 2011; Wyart et al., 2012a). It remains unclear, however, whether spatial attention can modulate Neural Representations of invisible stimuli that are in direct competition with highly salient and visible stimuli. Here we developed a novel electroencephalography (EEG) frequency-tagging paradigm to obtain a continuous readout of Neural activity associated with visible and invisible signals embedded in dynamic noise. Participants (N = 23) detected occasional contrast changes in one of two flickering image streams on either side of fixation. Each image stream contained a visible or invisible signal embedded in every second noise image, the visibility of which was titrated and checked using a two-interval forced-choice detection task. Steady-state visual-evoked potentials (SSVEPs) were computed from EEG data at the signal and noise frequencies of interest. Cluster-based permutation analyses revealed significant Neural responses to both visible and invisible signals across posterior scalp electrodes. In line with previous findings, spatial attention increased the Neural Representation of visible signals. Crucially, spatial attention also increased the Neural Representation of invisible signals. As such, the present results replicate and extend previous studies by demonstrating that attention can modulate the Neural Representation of invisible signals that are in direct competition with highly salient masking stimuli.
Cooper A. Smout - One of the best experts on this subject based on the ideXlab platform.
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Spatial Attention Enhances the Neural Representation of Invisible Signals Embedded in Noise
Journal of Cognitive Neuroscience, 2018Co-Authors: Cooper A. Smout, Jason B. MattingleyAbstract:Recent evidence suggests that voluntary spatial attention can affect Neural processing of visual stimuli that do not enter conscious awareness (i.e., invisible stimuli), supporting the notion that attention and awareness are dissociable processes [Wyart, V., Dehaene, S., & Tallon-Baudry, C. Early dissociation between Neural signatures of endogenous spatial attention and perceptual awareness during visual masking. Frontiers in Human Neuroscience, 6, 1–14, 2012; Watanabe, M., Cheng, K., Murayama, Y., Ueno, K., Asamizuya, T., Tanaka, K., et al. Attention but not awareness modulates the BOLD signal in the human V1 during binocular suppression. Science, 334, 829–831, 2011]. To date, however, no study has demonstrated that these effects reflect enhancement of the Neural Representation of invisible stimuli per se, as opposed to other Neural processes not specifically tied to the stimulus in question. In addition, it remains unclear whether spatial attention can modulate Neural Representations of invisible stimuli in direct competition with highly salient and visible stimuli. Here we developed a novel EEG frequency-tagging paradigm to obtain a continuous readout of human brain activity associated with visible and invisible signals embedded in dynamic noise. Participants (n = 23) detected occasional contrast changes in one of two flickering image streams on either side of fixation. Each image stream contained a visible or invisible signal embedded in every second noise image, the visibility of which was titrated and checked using a two-interval forced-choice detection task. Steady-state visual-evoked potentials were computed from EEG data at the signal and noise frequencies of interest. Cluster-based permutation analyses revealed significant Neural responses to both visible and invisible signals across posterior scalp electrodes. Control analyses revealed that these responses did not reflect a subharmonic response to noise stimuli. In line with previous findings, spatial attention increased the Neural Representation of visible signals. Crucially, spatial attention also increased the Neural Representation of invisible signals. As such, the present results replicate and extend previous studies by demonstrating that attention can modulate the Neural Representation of invisible signals that are in direct competition with highly salient masking stimuli.
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Spatial Attention Enhances the Neural Representation of Invisible Signals Embedded in Noise
bioRxiv, 2017Co-Authors: Cooper A. Smout, Jason B. MattingleyAbstract:Recent evidence suggests that voluntary spatial attention can modulate Neural Representations of visual stimuli that do not enter conscious awareness (i.e. invisible stimuli), supporting the notion that attention and awareness are dissociable processes (Watanabe et al., 2011; Wyart et al., 2012a). It remains unclear, however, whether spatial attention can modulate Neural Representations of invisible stimuli that are in direct competition with highly salient and visible stimuli. Here we developed a novel electroencephalography (EEG) frequency-tagging paradigm to obtain a continuous readout of Neural activity associated with visible and invisible signals embedded in dynamic noise. Participants (N = 23) detected occasional contrast changes in one of two flickering image streams on either side of fixation. Each image stream contained a visible or invisible signal embedded in every second noise image, the visibility of which was titrated and checked using a two-interval forced-choice detection task. Steady-state visual-evoked potentials (SSVEPs) were computed from EEG data at the signal and noise frequencies of interest. Cluster-based permutation analyses revealed significant Neural responses to both visible and invisible signals across posterior scalp electrodes. In line with previous findings, spatial attention increased the Neural Representation of visible signals. Crucially, spatial attention also increased the Neural Representation of invisible signals. As such, the present results replicate and extend previous studies by demonstrating that attention can modulate the Neural Representation of invisible signals that are in direct competition with highly salient masking stimuli.
John P Odoherty - One of the best experts on this subject based on the ideXlab platform.
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behavioral contagion during learning about another agent s risk preferences acts on the Neural Representation of decision risk
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Shinsuke Suzuki, Emily L S Jensen, Peter Bossaerts, John P OdohertyAbstract:Our attitude toward risk plays a crucial role in influencing our everyday decision-making. Despite its importance, little is known about how human risk-preference can be modulated by observing risky behavior in other agents at either the behavioral or the Neural level. Using fMRI combined with computational modeling of behavioral data, we show that human risk-preference can be systematically altered by the act of observing and learning from others’ risk-related decisions. The contagion is driven specifically by brain regions involved in the assessment of risk: the behavioral shift is implemented via a Neural Representation of risk in the caudate nucleus, whereas the Representations of other decision-related variables such as expected value are not affected. Furthermore, we uncover Neural computations underlying learning about others’ risk-preferences and describe how these signals interact with the Neural Representation of risk in the caudate. Updating of the belief about others’ preferences is associated with Neural activity in the dorsolateral prefrontal cortex (dlPFC). Functional coupling between the dlPFC and the caudate correlates with the degree of susceptibility to the contagion effect, suggesting that a frontal–subcortical loop, the so-called dorsolateral prefrontal–striatal circuit, underlies the modulation of risk-preference. Taken together, these findings provide a mechanistic account for how observation of others’ risky behavior can modulate an individual’s own risk-preference.
Alfonso Caramazza - One of the best experts on this subject based on the ideXlab platform.
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Neural Representation of visual concepts in people born blind
Nature Communications, 2018Co-Authors: Ella Striemamit, Xiaoying Wang, Yanchao Bi, Alfonso CaramazzaAbstract:How do we represent information without sensory features? How are abstract concepts like “freedom”, devoid of external perceptible referents, represented in the brain? Here, to address the role of sensory information in the Neural Representation of concepts, we used fMRI to investigate how people born blind process concepts whose referents are imperceptible to them because of their visual nature (“rainbow”, “red”). Activity for these concepts was compared to that of sensorially-perceptible referents (“rain”), classical abstract concepts (“justice”) and concrete concepts (“cup”), providing a gradient between fully concrete and fully abstract concepts in the blind. We find that anterior temporal lobe (ATL) responses track concept perceptibility and objecthood: preference for imperceptible object concepts was found in dorsal ATL, for abstract (non-object, non-referential) concepts in lateral ATL, and for perceptible concepts in medial ATL. These findings point to a new division-of-labor among aspects of ATL in representing conceptual properties that are abstract in different ways. How are abstract, imperceptible concepts such as ‘freedom’ represented in the brain? Here, the authors use fMRI in people born blind to compare the Neural responses for abstract concepts, concrete concepts like ‘rainbow’ which in blind people lack sensory qualities, and concrete concepts sensorily accessible to the blind.
Katharina Egger - One of the best experts on this subject based on the ideXlab platform.
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Supra-threshold perception and Neural Representation of tones presented in noise in conditions of masking release.
PLOS ONE, 2019Co-Authors: Katharina EggerAbstract:: The Neural Representation and perceptual salience of tonal signals presented in different noise maskers were investigated. The properties of the maskers and signals were varied such that they produced different amounts of either monaural masking release, binaural masking release, or a combination of both. The signals were then presented at different levels above their corresponding masked thresholds and auditory evoked potentials (AEPs) were measured. It was found that, independent of the masking condition, the amplitude of the P2 component of the AEP was similar for the same stimulus levels above masked threshold, suggesting that both monaural and binaural effects of masking release were represented at the level of the auditory pathway where P2 is generated. The perceptual salience of the signal was evaluated at equal levels above masked threshold using a rating task. In contrast to the electrophysiological findings, the subjective ratings of the perceptual signal salience were less consistent with the signal level above masked threshold and varied strongly across listeners and masking conditions. Overall, the results from the present study suggest that the P2 amplitude of the AEP represents an objective indicator of the audibility of a target signal in the presence of complex acoustic maskers.
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Supra-threshold perception and Neural Representation of tones presented in noise in conditions of masking release
bioRxiv, 2019Co-Authors: Katharina EggerAbstract:The Neural Representation and perceptual salience of tonal signals presented in different noise maskers were investigated. The properties of the maskers and signals were varied such that they produced different amounts of either monaural masking release, binaural masking release, or a combination of both. The signals were then presented at different levels above their corresponding masked thresholds and auditory evoked potentials (AEPs) were measured. It was found that, independent of the masking condition, the amplitude of the P2 component of the AEP was similar for the same stimulus levels above masked threshold, suggesting that both monaural and binaural effects of masking release were represented at the level of P2 generation. The perceptual salience of the signal was evaluated at equal levels above masked threshold using a rating task. In contrast to the electrophysiological findings, the subjective ratings of the perceptual signal salience were less consistent with the signal level above masked threshold and varied strongly across listeners and masking conditions. Overall, the results from the present study suggest that the P2 amplitude of the AEP represents an objective indicator of the audibility of a target signal in the presence of complex acoustic maskers.
