scholarly journals Phasic pupillary responses modulate object-based attentional prioritization

2021 ◽  
Author(s):  
Sean R. O’Bryan ◽  
Miranda Scolari
Keyword(s):  
Uncued Location ◽  
Salient Object ◽  
Top Down ◽  
Healthy Human ◽  
Object Selection ◽  
Pupillary Responses ◽  
Object Based ◽  
Human Participants ◽  
Enclosed Space ◽  
High Degree

AbstractVisual attention studies have demonstrated that the shape of space-based selection can be governed by salient object contours: when a portion of an enclosed space is cued, the selected region extends to the full enclosure. Although this form of object-based attention (OBA) is well established, one continuing investigation focuses on whether this selection is obligatory or under voluntary control. We attempt to dissociate between these alternatives by interrogating the locus coeruleus-norepinephrine (LC-NE) system – known to fluctuate with top-down attention – during a classic two-rectangle paradigm in a sample of healthy human participants (N = 36). An endogenous spatial pre-cue directed voluntary space-based attention (SBA) to one end of a rectangular frame. We manipulated the reliability of the cue, such that targets appearing at an uncued location within the frame occurred at low or moderate frequencies. Phasic pupillary responses time-locked to the cue display served to noninvasively measure LC-NE activity, reflecting top-down processing of the spatial cue. If OBA is controlled analogously to SBA, then object selection should emerge only when it is behaviorally expedient and when LC-NE activity reflects a high degree of top-down attention to the cue display. Our results bore this out. Thus, we conclude that OBA was voluntarily controlled, and furthermore show that phasic norepinephrine may modulate attentional strategy.

CSim 2

2021 ◽  
Vol 43 (1) ◽  
pp. 1-46
Author(s):  
David Sanan ◽  
Yongwang Zhao ◽  
Shang-Wei Lin ◽  
Liu Yang
Keyword(s):  
Programming Languages ◽  
Concurrent Systems ◽  
Theorem Prover ◽  
Compositional Techniques ◽  
Machine Code ◽  
Top Down ◽  
Hol Theorem Prover ◽  
High Level ◽  
High Degree

To make feasible and scalable the verification of large and complex concurrent systems, it is necessary the use of compositional techniques even at the highest abstraction layers. When focusing on the lowest software abstraction layers, such as the implementation or the machine code, the high level of detail of those layers makes the direct verification of properties very difficult and expensive. It is therefore essential to use techniques allowing to simplify the verification on these layers. One technique to tackle this challenge is top-down verification where by means of simulation properties verified on top layers (representing abstract specifications of a system) are propagated down to the lowest layers (that are an implementation of the top layers). There is no need to say that simulation of concurrent systems implies a greater level of complexity, and having compositional techniques to check simulation between layers is also desirable when seeking for both feasibility and scalability of the refinement verification. In this article, we present CSim 2 a (compositional) rely-guarantee-based framework for the top-down verification of complex concurrent systems in the Isabelle/HOL theorem prover. CSim 2 uses CSimpl, a language with a high degree of expressiveness designed for the specification of concurrent programs. Thanks to its expressibility, CSimpl is able to model many of the features found in real world programming languages like exceptions, assertions, and procedures. CSim 2 provides a framework for the verification of rely-guarantee properties to compositionally reason on CSimpl specifications. Focusing on top-down verification, CSim 2 provides a simulation-based framework for the preservation of CSimpl rely-guarantee properties from specifications to implementations. By using the simulation framework, properties proven on the top layers (abstract specifications) are compositionally propagated down to the lowest layers (source or machine code) in each concurrent component of the system. Finally, we show the usability of CSim 2 by running a case study over two CSimpl specifications of an Arinc-653 communication service. In this case study, we prove a complex property on a specification, and we use CSim 2 to preserve the property on lower abstraction layers.

scholarly journals Sex-related differences in response to masseteric injections of glutamate and nerve growth factor in healthy human participants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdelrahman M. Alhilou ◽  
Akiko Shimada ◽  
Camilla I. Svensson ◽  
Peter Svensson ◽  
Malin Ernberg ◽  
...  
Keyword(s):  
Nmda Receptors ◽  
Nerve Fiber ◽  
Masseter Muscle ◽  
Pain Sensitivity ◽  
Nerve Fibers ◽  
Receptor Expression ◽  
Healthy Human ◽  
Neurophysiological Mechanisms ◽  
Human Participants ◽  
Positive Correlations

AbstractThe neurophysiological mechanisms underlying NGF-induced masseter muscle sensitization and sex-related differences in its effect are not well understood in humans. Therefore, this longitudinal cohort study aimed to investigate the effect of NGF injection on the density and expression of substance P, NMDA-receptors and NGF by the nerve fibers in the human masseter muscle, to correlate expression with pain characteristics, and to determine any possible sex-related differences in these effects of NGF. The magnitude of NGF-induced mechanical sensitization and pain during oral function was significantly greater in women than in men (P < 0.050). Significant positive correlations were found between nerve fiber expression of NMDA-receptors and peak pain intensity (rs = 0.620, P = 0.048), and expression of NMDA-receptors by putative nociceptors and change in temporal summation pain after glutamate injection (rs = 0.561, P = 0.003). In women, there was a significant inverse relationship between the degree of NGF-induced mechanical sensitization and the change in nerve fiber expression of NMDA-receptors alone (rs = − 0.659, P = 0.013), and in combination with NGF (rs = − 0.764, P = 0.001). In conclusion, women displayed a greater magnitude of NGF-induced mechanical sensitization that also was associated with nerve fibers expression of NMDA-receptors, when compared to men. The present findings suggest that, in women, increased peripheral NMDA-receptor expression could be associated with masseter muscle pain sensitivity.

scholarly journals Color Can Shorten Breakthrough Times in Continuous Flash Suppression through Increased Salience and Task Relevance

Vision ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 13
Author(s):  
Christian Valuch
Keyword(s):  
Visual Search ◽  
Response Times ◽  
Top Down ◽  
Interocular Suppression ◽  
Continuous Flash Suppression ◽  
Task Relevance ◽  
Mediated Effects ◽  
Dominant Eye ◽  
Human Participants ◽  
And Task

Color can enhance the perception of relevant stimuli by increasing their salience and guiding visual search towards stimuli that match a task-relevant color. Using Continuous Flash Suppression (CFS), the current study investigated whether color facilitates the discrimination of targets that are difficult to perceive due to interocular suppression. Gabor patterns of two or four cycles per degree (cpd) were shown as targets to the non-dominant eye of human participants. CFS masks were presented at a rate of 10 Hz to the dominant eye, and participants had the task to report the target’s orientation as soon as they could discriminate it. The 2-cpd targets were robustly suppressed and resulted in much longer response times compared to 4-cpd targets. Moreover, only for 2-cpd targets, two color-related effects were evident. First, in trials where targets and CFS masks had different colors, targets were reported faster than in trials where targets and CFS masks had the same color. Second, targets with a known color, either cyan or yellow, were reported earlier than targets whose color was randomly cyan or yellow. The results suggest that the targets’ entry to consciousness may have been speeded by color-mediated effects relating to increased (bottom-up) salience and (top-down) task relevance.

Decoupling countermands nonselective response inhibition during selective stopping

2021 ◽  
Author(s):  
Corey George Wadsley ◽  
John Cirillo ◽  
Arne Nieuwenhuys ◽  
Winston D Byblow
Keyword(s):  
Response Inhibition ◽  
Interference Effect ◽  
Complex Form ◽  
Functional Coupling ◽  
Response Preparation ◽  
Response Delay ◽  
Healthy Human ◽  
Human Participants ◽  
Goal Directed Behavior ◽  
Effector Response

Response inhibition is essential for goal-directed behavior within dynamic environments. Selective stopping is a complex form of response inhibition where only part of a multi-effector response must be cancelled. A substantial response delay emerges on unstopped effectors when a cued effector is successfully stopped. This stopping-interference effect is indicative of nonselective response inhibition during selective stopping which may, in-part, be a consequence of functional coupling. The present study examined selective stopping of (de)coupled bimanual responses in healthy human participants of either sex. Participants performed synchronous and asynchronous versions of an anticipatory stop-signal paradigm across two sessions while mu (µ) and beta (β) rhythm were measured with electroencephalography. Results showed that responses were behaviorally decoupled during asynchronous go trials and the extent of response asynchrony was associated with lateralized sensorimotor µ and β desynchronization during response preparation. Selective stopping produced a stopping-interference effect and was marked by a nonselective increase and subsequent rebound in prefrontal and sensorimotor β. In support of the coupling account, stopping-interference was smaller during selective stopping of asynchronous responses, and negatively associated with the magnitude of decoupling. However, the increase in sensorimotor β during selective stopping was equivalent between the stopped and unstopped hand irrespective of response synchrony. Overall, the findings demonstrate that decoupling facilitates selective stopping after a global pause process and emphasizes the importance of considering the influence of both the go and stop context when investigating response inhibition.

Absence of systematic relationships between REMS duration episodes and spectral power Delta and Ultra-Slow bands in contiguous NREMS episodes in healthy humans

2013 ◽  
Vol 110 (1) ◽  
pp. 162-169 ◽  
Author(s):  
O. Le Bon ◽  
P. Linkowski
Keyword(s):  
Spectral Power ◽  
Sleep Cycle ◽  
Consecutive Series ◽  
Sleep Regulation ◽  
Healthy Human ◽  
Sleep Quantity ◽  
Healthy Humans ◽  
Crucial Component ◽  
Sleep Physiology ◽  
Human Participants

Previous studies in animals and humans have reported correlations between the durations of rapid eye movement sleep (REMS) episodes and immediately preceding or subsequent non-REMS (NREMS) episodes. The relationship between these two types of sleep is a crucial component in understanding the regulation and neurophysiology of ultradian alternations that occur during sleep. Although the present study replicated previous studies, we also measured NREMS in terms of spectral power Delta and Ultra-Slow bands in addition to duration in examining correlations. The spectral power Delta band, also known as slow-wave activity, measures sleep quantity and is believed to reflect sleep physiology better than mere episode durations. The Ultra-Slow spectral power band was analyzed in parallel. Healthy human participants of both sexes ( n = 26, age range 15–45 yr, n = 12 female) were carefully selected to participate in two consecutive series of home polysomnograms performed after 2 nights of habituation to the equipment. In the analyses, REMS episode durations (minutes) were compared with immediately preceding and immediately subsequent NREMS episodes (Delta and Ultra-Slow power) in each sleep cycle. REMS episode duration was more strongly correlated with preceding NREMS episodes than with subsequent NREMS episodes. However, in most cases, no correlations were observed in either direction. One ultradian sleep regulation hypothesis, which is based on stronger correlations between REMS and subsequent NREMS episode durations, holds that the main purpose of REMS is to reactivate NREMS during each sleep cycle. The present results do not support that hypothesis.

scholarly journals Top-down biasing signals of non-spatial, object-based attention

2015 ◽  
Vol 15 (12) ◽  
pp. 1395 ◽  
Author(s):  
Daniel Baldauf
Keyword(s):  
Top Down ◽  
Spatial Object ◽  
Object Based

scholarly journals Evaluation of top-down mass spectrometry and ion-mobility spectroscopy as a means of mapping protein-binding motifs within heparin chains

The Analyst ◽  
2020 ◽  
Vol 145 (8) ◽  
pp. 3090-3099 ◽  
Author(s):  
Yunlong Zhao ◽  
Igor A. Kaltashov
Keyword(s):  
Mass Spectrometry ◽  
Protein Binding ◽  
Ion Mobility ◽  
Structural Elements ◽  
Client Protein ◽  
Top Down ◽  
Binding Motifs ◽  
Ion Mobility Spectroscopy ◽  
High Degree ◽  
Top Down Mass Spectrometry

Identifying structural elements within glycosaminoglycans that enable their interaction with a specific client protein remains a challenging task due to the high degree of both intra- and inter-chain heterogeneity exhibited by this polysaccharide.

scholarly journals Antioxidant Activity with Increased Endogenous Levels of Vitamin C, E and A Following Dietary Supplementation with a Combination of Glutathione and Resveratrol Precursors

Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3224 ◽  
Author(s):  
Priscilla Biswas ◽  
Cinzia Dellanoce ◽  
Alessandra Vezzoli ◽  
Simona Mrakic-Sposta ◽  
Mauro Malnati ◽  
...  
Keyword(s):  
Dietary Supplements ◽  
Immune Status ◽  
Inflammatory Marker ◽  
Dietary Supplementation ◽  
Positive Outcome ◽  
Redox Status ◽  
Healthy Human ◽  
Treatment Groups ◽  
Human Participants ◽  
Endogenous Synthesis

The effects of two different dietary supplements on the redox status of healthy human participants were evaluated. The first supplement (GluS, Glutathione Synthesis) contains the precursors for the endogenous synthesis of glutathione and the second (GluReS, Glutathione and Resveratrol Synthesis) contains in addition polydatin, a precursor of resveratrol. To assess the influence of GluS and GluReS on the redox status, ten thiol species and three vitamins were measured before (t0) and after 8 weeks (t1) of dietary supplementation. An inflammatory marker, neopterin, was also assessed at the same time points. Both supplements were highly effective in improving the redox status by significantly increasing the reduced-glutathione (GSH) content and other reduced thiol species while significantly decreasing the oxidized species. The positive outcome of the redox status was most significant in the GluRes treatment group which also experienced a significant reduction in neopterin levels. Of note, the endogenous levels of vitamins C, E and A were significantly increased in both treatment groups, with best results in the GluReS group. While both dietary supplements significantly contributed to recognized antioxidant and anti-inflammatory outcomes, the effects of GluReS, the combination of glutathione and resveratrol precursors, were more pronounced. Thus, dietary supplementation with GluReS may represent a valuable strategy for maintaining a competent immune status and a healthy lifespan.

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