scholarly journals Preparatory Template Activation during Search for Alternating Targets

2020 ◽  
Vol 32 (8) ◽  
pp. 1525-1535
Author(s):  
Anna Grubert ◽  
Martin Eimer
Keyword(s):  
Executive Control ◽  
Attentional Control ◽  
Time Course ◽  
Search Display ◽  
Target Color ◽  
Target Template ◽  
Target Templates ◽  
Irrelevant Color ◽  
Task Irrelevant ◽  
Time Point

Visual search is guided by representations of target-defining features (attentional templates). We tracked the time course of template activation processes during the preparation for search in a task where the identity of color-defined search targets switched across successive trials (ABAB). Task-irrelevant color probes that matched either the upcoming relevant target color or the previous now-irrelevant target color were presented every 200 msec during the interval between search displays. N2pc components (markers of attentional capture) were measured for both types of probes at each time point. A reliable probe N2pc indicates that the corresponding color template is active at the time when the probe appears. N2pcs of equal size emerged from 1000 msec before search display onset for both relevant-color and irrelevant-color probes, demonstrating that both color templates were activated concurrently. Evidence for color-selective attentional control was found only immediately before the arrival of the search display, where N2pcs were larger for relevant-color probes. These results reveal important limitations in the executive control of search preparation in tasks where two targets alternate across trials. Although the identity of the upcoming target is fully predictable, both task-relevant and task-irrelevant target templates are coactivated. Knowledge about target identity selectively biases these template activation processes in a temporally discrete fashion, guided by temporal expectations about when the target template will become relevant.

scholarly journals Dissociating Reward- and Attention-driven Biasing of Global Feature-based Selection in Human Visual Cortex

2019 ◽  
Vol 31 (4) ◽  
pp. 469-481 ◽  
Author(s):  
Haydee G. Garcia-Lazaro ◽  
Mandy V. Bartsch ◽  
Carsten N. Boehler ◽  
Ruth M. Krebs ◽  
Sarah E. Donohue ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Target Selection ◽  
Target Color ◽  
Selective Area ◽  
Early Visual Cortex ◽  
Feature Based ◽  
Irrelevant Color ◽  
Task Irrelevant ◽  
Open Question ◽  
Attention Demands

Objects that promise rewards are prioritized for visual selection. The way this prioritization shapes sensory processing in visual cortex, however, is debated. It has been suggested that rewards motivate stronger attentional focusing, resulting in a modulation of sensory selection in early visual cortex. An open question is whether those reward-driven modulations would be independent of similar modulations indexing the selection of attended features that are not associated with reward. Here, we use magnetoencephalography in human observers to investigate whether the modulations indexing global color-based selection in visual cortex are separable for target- and (monetary) reward-defining colors. To assess the underlying global color-based activity modulation, we compare the event-related magnetic field response elicited by a color probe in the unattended hemifield drawn either in the target color, the reward color, both colors, or a neutral task-irrelevant color. To test whether target and reward relevance trigger separable modulations, we manipulate attention demands on target selection while keeping reward-defining experimental parameters constant. Replicating previous observations, we find that reward and target relevance produce almost indistinguishable gain modulations in ventral extratriate cortex contralateral to the unattended color probe. Importantly, increasing attention demands on target discrimination increases the response to the target-defining color, whereas the response to the rewarded color remains largely unchanged. These observations indicate that, although task relevance and reward influence the very same feature-selective area in extrastriate visual cortex, the associated modulations are largely independent.

scholarly journals Task-Irrelevant Features in Visual Working Memory Influence Covert Attention: Evidence from a Partial Report Task

Vision ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 42 ◽  
Author(s):  
Rebecca M. Foerster ◽  
Werner X. Schneider
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Shape Matching ◽  
Target Location ◽  
Covert Attention ◽  
Partial Report ◽  
Target Color ◽  
Color Target ◽  
Irrelevant Color ◽  
Task Irrelevant

Selecting a target based on a representation in visual working memory (VWM) affords biasing covert attention towards objects with memory-matching features. Recently, we showed that even task-irrelevant features of a VWM template bias attention. Specifically, when participants had to saccade to a cued shape, distractors sharing the cue’s search-irrelevant color captured the eyes. While a saccade always aims at one target location, multiple locations can be attended covertly. Here, we investigated whether covert attention is captured similarly as the eyes. In our partial report task, each trial started with a shape-defined search cue, followed by a fixation cross. Next, two colored shapes, each including a letter, appeared left and right from fixation, followed by masks. The letter inside that shape matching the preceding cue had to be reported. In Experiment 1, either target, distractor, both, or no object matched the cue’s irrelevant color. Target-letter reports were most frequent in target-match trials and least frequent in distractor-match trials. Irrelevant cue and target color never matched in Experiment 2. Still, participants reported the distractor more often to the target’s disadvantage, when cue and distractor color matched. Thus, irrelevant features of a VWM template can influence covert attention in an involuntarily object-based manner when searching for trial-wise varying targets.

scholarly journals Distraction by deviant sounds during reading: An eye-movement study

2019 ◽  
Vol 72 (7) ◽  
pp. 1863-1875 ◽  
Author(s):  
Martin R Vasilev ◽  
Fabrice BR Parmentier ◽  
Bernhard Angele ◽  
Julie A Kirkby
Keyword(s):  
Eye Movements ◽  
Time Course ◽  
Lexical Processing ◽  
Repeated Sequence ◽  
Reading Performance ◽  
Sequence Capture ◽  
Fixation Durations ◽  
Movement Study ◽  
Task Irrelevant ◽  
Target Words

Oddball studies have shown that sounds unexpectedly deviating from an otherwise repeated sequence capture attention away from the task at hand. While such distraction is typically regarded as potentially important in everyday life, previous work has so far not examined how deviant sounds affect performance on more complex daily tasks. In this study, we developed a new method to examine whether deviant sounds can disrupt reading performance by recording participants’ eye movements. Participants read single sentences in silence and while listening to task-irrelevant sounds. In the latter condition, a 50-ms sound was played contingent on the fixation of five target words in the sentence. On most occasions, the same tone was presented (standard sound), whereas on rare and unexpected occasions it was replaced by white noise (deviant sound). The deviant sound resulted in significantly longer fixation durations on the target words relative to the standard sound. A time-course analysis showed that the deviant sound began to affect fixation durations around 180 ms after fixation onset. Furthermore, deviance distraction was not modulated by the lexical frequency of target words. In summary, fixation durations on the target words were longer immediately after the presentation of the deviant sound, but there was no evidence that it interfered with the lexical processing of these words. The present results are in line with the recent proposition that deviant sounds yield a temporary motor suppression and suggest that deviant sounds likely inhibit the programming of the next saccade.

Impact of ejection on magnitude and time course of ventricular pressure-generating capacity

1993 ◽  
Vol 265 (3) ◽  
pp. H899-H909 ◽  
Author(s):  
D. Burkhoff ◽  
P. P. De Tombe ◽  
W. C. Hunter
Keyword(s):  
Time Course ◽  
Cardiac Cycle ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Time Varying ◽  
Generating Capacity ◽  
Ejection Phase ◽  
Time Point ◽  
Ventricular Dynamics

This study focuses on elucidating how ventricular afterloading conditions affect the time course of change of left ventricular pressure (LVP) throughout the cardiac cycle, with particular emphasis on revealing specific limitations in the time-varying elastance model of ventricular dynamics. Studies were performed in eight isolated canine hearts ejecting into a simulated windkessel afterload. LVP waves measured (LVPm) during ejection were compared with those predicted (LVPpred) according to the elastance theory. LVPm exceeded LVPpred from a time point shortly after the onset of ejection to the end of the beat. The instantaneous difference between LVPm and LVPpred increased steadily as ejection proceeded and reached between 45 and 65 mmHg near end ejection. This was in large part due to an average 35-ms prolongation of the time to end systole (tes) in ejecting compared with isovolumic beats. The time constant of relaxation was decreased on ejecting beats so that, despite the marked prolongation of tes, the overall duration of ejecting contractions was not greater than that of isovolumic beats. The results demonstrate a marked ejection-mediated enhancement and prolongation of ventricular pressure-generating capacity during the ejection phase of the cardiac cycle with concomitant acceleration of relaxation. None of these factors are accounted for by the time-varying elastance theory.

scholarly journals RNA-Seq Transcriptome Analysis of Peripheral Blood From Cattle Infected With Mycobacterium bovis Across an Experimental Time Course

2021 ◽  
Vol 8 ◽  
Author(s):  
Kirsten E. McLoughlin ◽  
Carolina N. Correia ◽  
John A. Browne ◽  
David A. Magee ◽  
Nicolas C. Nalpas ◽  
...  
Keyword(s):  
Differentially Expressed Genes ◽  
Mycobacterium Bovis ◽  
Peripheral Blood ◽  
Post Infection ◽  
Time Course ◽  
De Novo ◽  
Differentially Expressed Gene ◽  
Differentially Expressed ◽  
Infection Time ◽  
Time Point

Bovine tuberculosis, caused by infection with members of the Mycobacterium tuberculosis complex, particularly Mycobacterium bovis, is a major endemic disease affecting cattle populations worldwide, despite the implementation of stringent surveillance and control programs in many countries. The development of high-throughput functional genomics technologies, including RNA sequencing, has enabled detailed analysis of the host transcriptome to M. bovis infection, particularly at the macrophage and peripheral blood level. In the present study, we have analysed the transcriptome of bovine whole peripheral blood samples collected at −1 week pre-infection and +1, +2, +6, +10, and +12 weeks post-infection time points. Differentially expressed genes were catalogued and evaluated at each post-infection time point relative to the −1 week pre-infection time point and used for the identification of putative candidate host transcriptional biomarkers for M. bovis infection. Differentially expressed gene sets were also used for examination of cellular pathways associated with the host response to M. bovis infection, construction of de novo gene interaction networks enriched for host differentially expressed genes, and time-series analyses to identify functionally important groups of genes displaying similar patterns of expression across the infection time course. A notable outcome of these analyses was identification of a 19-gene transcriptional biosignature of infection consisting of genes increased in expression across the time course from +1 week to +12 weeks post-infection.

scholarly journals Higher availability of α4β2 nicotinic receptors (nAChRs) in dorsal ACC is linked to more efficient interference control

2019 ◽  
Author(s):  
Swann Pichon ◽  
Garibotto Valentina ◽  
Wissmeyer Michael ◽  
Seimbille Yann ◽  
Lia Antico ◽  
...  
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Attentional Control ◽  
Acetylcholine Receptors ◽  
Anterior Cingulate ◽  
Interference Control ◽  
Dorsal Anterior Cingulate Cortex ◽  
Behavioral Measures ◽  
Attentional Processes ◽  
Task Irrelevant ◽  
Male Subjects

Nicotinic acetylcholine receptors (nAChRs) are widely distributed in the human brain and play an important role in the neuromodulation of brain networks implicated in attentional processes. Previous work in humans showed that heteromeric α4β2 nAChRs are abundant in the cingulo-insular network underlying attentional control. It has been proposed that cholinergic neuromodulation by α4β2 nAChRs is involved in attentional control during demanding tasks, when additional resources are needed to minimize interference from task-irrelevant stimuli and focus on task-relevant stimuli. Here we investigate the link between the availability of α4β2 nAChRs in the cingulo-insular network and behavioral measures of interference control using two versions of the Stroop paradigm, a task known to recruit cingulo-insular areas. We used a previously published PET dataset acquired 24 non-smoking male subjects in the context of a larger study which investigated the brain distribution of nAChRs in two clinical groups using 2-[(18)F]F-A-85380 PET. We found that higher availability of α4β2 nAChRs in the dorsal anterior cingulate cortex (ACC) predicted better interference control independently of group and age. In line with animal models, our results support the view that the availability of α4β2 nAChRs in the dorsal ACC is linked with more efficient attentional control.

scholarly journals Systemic Effects of Selection History on Learned Ignoring

2021 ◽  
Author(s):  
Andy Jeesu Kim ◽  
Brian A. Anderson
Keyword(s):  
Eye Movements ◽  
Reaction Time ◽  
Young Adult ◽  
High Probability ◽  
Time Course ◽  
Systemic Effects ◽  
Reduced Frequency ◽  
Selection History ◽  
Adult Participants ◽  
Task Irrelevant

Despite our best intentions, physically salient but entirely task-irrelevant stimuli can sometimes capture our attention. With learning, it is possible to more efficiently ignore such stimuli, although specifically how the visual system accomplishes this remains to be clarified. Using a sample of young-adult participants, we examined the time course of eye movements to targets and distractors. We replicate a reduced frequency of eye movements to the distractor when appearing in a location at which distractors are frequently encountered. This reduction was observed even for the earliest saccades, when selection tends to be most stimulus-driven. When the distractor appeared at the high-probability location, saccadic reaction time was slowed specifically for distractor-going saccades, suggesting a slowing of priority accumulation at this location. In the event that the distractor was fixated, disengagement from the distractor was also faster when it appeared in the high-probability location. Both proactive and reactive mechanisms of distractor suppression work together to minimize attentional capture by frequently-encountered distractors.

Drawn to Distraction: Anxiety Impairs Neural Suppression of Known Distractor Features in Visual Search

2021 ◽  
pp. 1-13
Author(s):  
Christine Salahub ◽  
Stephen M. Emrich
Keyword(s):  
Visual Search ◽  
Attentional Control ◽  
Template Matching ◽  
Time Course ◽  
High Anxiety ◽  
Guided Search ◽  
Distractor Processing ◽  
Search And Destroy

Abstract When searching for a target, it is possible to suppress the features of a known distractor. This suppression may prevent distractor processing altogether or only after the distractor initially captures attention (i.e., search and destroy). However, suppression may be impaired in individuals with attentional control deficits, such as in high anxiety. In this study (n = 48), we used ERPs to examine the time course of attentional enhancement and suppression when participants were given pretrial information about target or distractor features. Consistent with our hypothesis, we found that individuals with higher levels of anxiety had lower neural measures of suppressing the template-matching distractor, instead showing enhanced processing. These findings indicate that individuals with anxiety are more likely to use a search-and-destroy mechanism of negative templates—highlighting the importance of attentional control abilities in distractor-guided search.

scholarly journals Dynamic target template matching for railway catenary suspension motion detection in wind area

2018 ◽  
Vol 14 (9) ◽  
pp. 155014771879795 ◽  
Author(s):  
Wei Zhou ◽  
Heting Xiao ◽  
Zhonggang Wang ◽  
Lin Chen ◽  
Shaoqing Fu
Keyword(s):  
Template Matching ◽  
Three Dimensional ◽  
Moving Target ◽  
Maximum Relative Error ◽  
Gradual Change ◽  
Matching Method ◽  
Safety Research ◽  
Target Template ◽  
Target Templates ◽  
Dynamic Target

A dynamic target template matching method was proposed to identify railway catenary suspension movements of wind-induced vibration in wind area. Catenary positioning point was taken as the target template, which was compared with equal-sized image sequentially using the proposed matching difference. And, three-dimensional contour map of matching difference value at each sub-area was obtained, where the target pixel coordinates were determined by the minimum matching difference value. Considering the complex imaging condition, the target template was updated by the detected target image to sense the gradual change of illumination conditions like brightness and contrast. Furthermore, to eliminate detecting errors due to wind-induced camera vibration, both static and moving target templates were identified for acquiring the absolute motion of the moving target. Finally, validation test was performed with animation in PowerPoint. The calculated target displacement agrees well with theoretical motion with maximum relative error of 1.8%. And experiment application was conducted at site by analyzing the relationship between detecting displacement and wind speed. Results indicate that the proposed dynamic target template matching method can meet required engineering precision and provide an effective way for wind-vibration safety research of railway catenary system in wind area.

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