Types Of Distractors Research Articles

Classification of Movement Preparation Between Attended and Distracted Self-Paced Motor Tasks.

Brain-computer interface (BCI) systems aim to control external devices by using brain signals. The performance of these systems is influenced by the user's mental state, such as attention. In this study, we classified two attention states to a target task (attended and distracted task level) while attention to the task is altered by one of three types of distractors. A total of 27 participants were allocated into three experimental groups and exposed to one type of distractor. An attended condition that was the same across the three groups comprised only the main task execution (self-paced dorsiflexion) while the distracted condition was concurrent execution of the main task and an oddball task (dual-task condition). Electroencephalography signals were recorded from 28 electrodes to classify the two attention states of attended or distracted task conditions by extracting temporal and spectral features. The results showed that the ensemble classification accuracy using the combination of temporal and spectral features (spectro-temporal features, 82.3 ± 2.7%) was greater than using temporal (69 ± 2.2%) and spectral (80.3 ± 2.6%) features separately. The classification accuracy was computed using a combination of different channel locations, and it was demonstrated that a combination of parietal and centrally located channels was superior for classification of two attention states during movement preparation (parietal channels: 84.6 ± 1.3%, central and parietal channels: 87.2 ± 1.5%). It is possible to monitor the users' attention to the task for different types of distractors. It has implications for online BCI systems where the requirement is for high accuracy of intention detection.

Dwelling on distractors varying in target-distractor similarity

Present day models of visual search focus on explaining search efficiency by visual guidance: The target guides attention to the target's position better in more efficient than in less efficient search. The time spent processing the distractor, however, is set to a constant in these models. In contrast to this assumption, recent studies found that dwelling on distractors is longer in more inefficient search. Previous experiments in support of this contention all presented the same distractors across all conditions, while varying the targets. While this procedure has its virtues, it confounds the manipulation of search efficiency with target type. Here we use the same targets over the entire experiment, while varying search efficiency by presenting different types of distractors. Eye fixation behavior was used to infer the amount of distractor dwelling, skipping, and revisiting. The results replicate previous results, with similarity affecting dwelling, and dwelling in turn affecting search performance. A regression analysis confirmed that variations in dwelling account for a large amount of variance in search speed, and that the similarity effect in dwelling accounts for the similarity effect in overall search performance.

The time-course of component processes of selective attention

Attentional selection shapes human perception, enhancing relevant information, according to behavioral goals. While many studies have investigated individual neural signatures of attention, here we used multivariate decoding of electrophysiological brain responses (MEG/EEG) to track and compare multiple component processes of selective attention. Auditory cues instructed participants to select a particular visual target, embedded within a subsequent stream of displays. Combining single and multi-item displays with different types of distractors allowed multiple aspects of information content to be decoded, distinguishing distinct components of attention, as the selection process evolved. Although the task required comparison of items to an attentional “template” held in memory, signals consistent with such a template were largely undetectable throughout the preparatory period but re-emerged after presentation of a non-target choice display. Choice displays evoked strong neural representation of multiple target features, evolving over different timescales. We quantified five distinct processing operations with different time-courses. First, visual properties of the stimulus were strongly represented. Second, the candidate target was rapidly identified and localized in multi-item displays, providing the earliest evidence of modulation by behavioral relevance. Third, the identity of the target continued to be enhanced, relative to distractors. Fourth, only later was the behavioral significance of the target explicitly represented in single-item displays. Finally, if the target was not identified and search was to be resumed, then an attentional template was weakly reactivated. The observation that an item's behavioral relevance directs attention in multi-item displays prior to explicit representation of target/non-target status in single-item displays is consistent with two-stage models of attention.

The Functional Consequences of Social Attention for Memory-guided Attention Orienting and Anticipatory Neural Dynamics.

Social attention when viewing natural social (compared with nonsocial) images has functional consequences on contextual memory in healthy human adults. In addition to attention affecting memory performance, strong evidence suggests that memory, in turn, affects attentional orienting. Here, we ask whether the effects of social processing on memory alter subsequent memory-guided attention orienting and corresponding anticipatory dynamics of 8-12 Hz alpha-band oscillations as measured with EEG. Eighteen young adults searched for targets in scenes that contained either social or nonsocial distracters and their memory precision tested. Subsequently, RT was measured as participants oriented to targets appearing in those scenes at either valid (previously learned) locations or invalid (different) locations. Memory precision was poorer for target locations in social scenes. In addition, distractor type moderated the validity effect during memory-guided attentional orienting, with a larger cost in RT when targets appeared at invalid (different) locations within scenes with social distractors. The poorer memory performance was also marked by reduced anticipatory dynamics of spatially lateralized 8-12 Hz alpha-band oscillations for scenes with social distractors. The functional consequences of a social attention bias therefore extend from memory to memory-guided attention orienting, a bidirectional chain that may further reinforce attentional biases.

How feature relationships influence attention and awareness: Evidence from eye movements and EEG.

Many everyday tasks require selecting relevant objects in the visual field while ignoring irrelevant information. A widely held belief is that attention is tuned to the exact feature value(s) of a sought-after target object (e.g., color, shape). In contrast, subsequent studies have shown that attentional orienting (capture) is often determined by the relative feature(s) that the target has relative to other irrelevant items surrounding (e.g., redder, larger). However, it is unknown whether conscious awareness is also determined by relative features. Alternatively, awareness could be more strongly determined by exact feature values, which seem to determine dwelling on objects. The present study examined eye movements in a color search task with different types of irrelevant distractors to test (a) whether dwelling is more strongly influenced by exact feature matches than relative matches, and (b) which of the processes (capture vs. dwelling) is more important for conscious awareness of the distractor. A second experiment used an electrophysiological marker of attention (N2pc in the electroencephalogram of participants) to test whether the results generalize to covert attention shifts. As expected, the results revealed that the initial capture of attention was strongest for distractors matching the relative color of the target, whereas similarity to the target was the most important determiner for dwelling. Awareness was more strongly determined by the initial capture of attention than dwelling. These results provide important insights into the interplay of attention and awareness and highlight the importance of considering relative, context-dependent features in theories of awareness. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Dual-tasking with simple linguistic tasks: Evidence for serial processing

In contrast to the large amount of dual-task research investigating the coordination of a linguistic and a non-linguistic task, little research has investigated how two linguistic tasks are coordinated. However, such research would greatly contribute to our understanding of how interlocutors combine speech planning and listening in conversation. In three dual-task experiments we studied how participants coordinated the processing of an auditory stimulus (S1), which was either a syllable or a tone, with selecting a name for a picture (S2). Two SOAs, of 0 ms and 1000 ms, were used. To vary the time required for lexical selection and to determine when lexical selection took place, the pictures were presented with categorically related or unrelated distractor words. In Experiment 1 participants responded overtly to both stimuli. In Experiments 2 and 3, S1 was not responded to overtly, but determined how to respond to S2, by naming the picture or reading the distractor aloud. Experiment 1 yielded additive effects of SOA and distractor type on the picture naming latencies. The presence of semantic interference at both SOAs indicated that lexical selection occurred after response selection for S1. With respect to the coordination of S1 and S2 processing, Experiments 2 and 3 yielded inconclusive results. In all experiments, syllables interfered more with picture naming than tones. This is likely because the syllables activated phonological representations also implicated in picture naming. The theoretical and methodological implications of the findings are discussed.

Symphyseal bone distraction (part 1): benefit / risk ratio. A systematic literature review

The purpose of this systematic literature review is to evaluate the benefit / risk ratio of mandibular symphyseal distraction osteogenesis. Searches were made on Pubmed/Medline and Cochrane for randomized clinical trials and case series involving mandibular symphyseal distraction over the past 20 years with a patient sample greater than or equal to 10. Of the 92 articles, 25 met the inclusion criteria. A controlled trial was selected, but no randomized trial. The other studies were all case series, 16 retrospective and 8 prospective. Distractors with bone or hybrid anchorage appear to lead to more periodontal and infectious complications due to the buccal position of the jack. Most complications are benign. However, the most difficult event to deal with is distraction device fracture. Symphyseal midline distraction increases the transverse dimension efficiently, reliably and sustainably, and appears to have no demonstrated deleterious effects on the ATMs for the three types of distractors. Tooth-borne devices are recommended in most cases given their benefit / risk ratio. Furthermore, they do not require a second surgical procedure to remove them. Mandibular symphyseal distraction osteogenesis is a reliable therapy whose exact limits and reproducibility remain to be defined by future prospective studies.

Age-Related Developmental and Individual Differences in the Influence of Social and Non-social Distractors on Cognitive Performance.

This study sought to examine age-related differences in the influences of social (neutral, emotional faces) and non-social/non-emotional (shapes) distractor stimuli in children, adolescents, and adults. To assess the degree to which distractor, or task-irrelevant, stimuli of varying social and emotional salience interfere with cognitive performance, children (N = 12; 8–12y), adolescents (N = 17; 13–17y), and adults (N = 17; 18–52y) completed the Emotional Identification and Dynamic Faces (EIDF) task. This task included three types of dynamically-changing distractors: (1) neutral-social (neutral face changing into another face); (2) emotional-social (face changing from 0% emotional to 100% emotional); and (3) non-social/non-emotional (shapes changing from small to large) to index the influence of task-irrelevant social and emotional information on cognition. Results yielded no age-related differences in accuracy but showed an age-related linear reduction in correct reaction times across distractor conditions. An age-related effect in interference was observed, such that children and adults showed slower response times on correct trials with socially-salient distractors; whereas adolescents exhibited faster responses on trials with distractors that included faces rather than shapes. A secondary study goal was to explore individual differences in cognitive interference. Results suggested that regardless of age, low trait anxiety and high effortful control were associated with interference to angry faces. Implications for developmental differences in affective processing, notably the importance of considering the contexts in which purportedly irrelevant social and emotional information might impair, vs. improve cognitive control, are discussed.

Testing assumptions on prefrontal transcranial direct current stimulation: Comparison of electrode montages using multimodal fMRI

BackgroundTranscranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) has been widely applied in cognitive neurosciences and advocated as a therapeutic intervention, e.g. in major depressive disorder. Although several targets and protocols have been suggested, comparative studies of tDCS parameters, particularly electrode montages and their cortical targets, are still lacking. ObjectiveThis study investigated a priori hypotheses on specific effects of prefrontal-tDCS montages by using multimodal functional magnetic resonance imaging (fMRI) in healthy participants. Methods28 healthy male participants underwent three common active-tDCS montages and sham tDCS in a pseudo-randomized order, comprising a total of 112 tDCS-fMRI sessions. Active tDCS was applied at 2 mA for 20 min. Before and after tDCS, a resting-state fMRI (RS fMRI) was recorded, followed by a task fMRI with a delayed-response working-memory (DWM) task for assessing cognitive control over emotionally negative or neutral distractors. ResultsAfter tDCS with a cathode-F3/anode-F4 montage, RS-fMRI connectivity decreased in a medial part of the left PFC. Also, after the same stimulation condition, regional brain activity during DWM retrieval decreased more in this area after negative than after neutral distraction, and responses to the DWM task were faster, independent of distractor type. ConclusionThe current study does not confirm our a priori hypotheses on direction and localization of polarity-dependent tDCS effects using common bipolar electrode montages over PFC regions, but it provides evidence for montage-specific effects on multimodal neurophysiological and behavioral outcome measures. Systematic research on the actual targets and the respective dose-response relationships of prefrontal tDCS is warranted.

Retroactive Interference in Visual Short-Term Memory.

Retroactive interference occurs when new information disrupts the retention of an existing representation, but its effects on visual short-term memory remain poorly understood. The present study examined three factors predicted to influence domain-specific retroactive interference, including the type of distractor, its temporal position, and the length of the retention interval. Participants compared target and test objects over a brief interval that either was unfilled or contained a similar or dissimilar distractor occurring 200ms or 1.5s after the target offset. Retention was influenced by the temporal position of the distractor and its relationship with the to-be-remembered target. Specifically, retroactive interference was only observed following the presentation of a dissimilar distractor that occurred 1.5s after the target. These results suggest that novel distractors may be particularly interfering.

Modified Le Fort III osteotomy: A simple solution to severe midfacial hypoplasia

PurposeThere are multiple conditions that may affect the development of the middle third of the face and with varying degrees of severity. The surgical treatment alternatives for major midfacial sagittal deficiencies consist in Le Fort I, II, or III with conventional osteotomies or with distraction osteogenesis (DO). Both techniques have advantages and disadvantages that should be evaluated specifically in each case. The aim of this report is to present a group of patients with severe hypoplasia of the middle third of the face, with different origins, and their treatment with a Modified Le Fort III osteotomy and distraction osteogenesis, using a minimally invasive surgical approach. Materials and methodsThe surgical technique was performed in a group of patients with severe hypoplasia of the middle third of the face, through a transconjunctival approach with lateral canthotomy and a trans-oral approach. The osteotomy consisted of a Le Fort III without the nasofrontal component. A rigid external distractor (RED) type II or internal distractor was installed. The amount of distraction, surgical time, blood loss, and complications were evaluated. ResultsA total of 7 patients underwent operation, 5 men and 2 women with an average age of 20.8 (range 11–41) years; 3 patients with Crouzon syndrome, 2 with Pfeiffer syndrome, 1 patient with cleft lip and palate sequel, and 1 with a severe non-syndromic class III. The average follow-up was 3.14 years. All patients achieved stable occlusion without postoperative changes, positive overbite and overjet, without relapse in the skeletal position. The average advancement was 14.7 (±4.07) mm, in 1.1 incisors, and 15.2 (±3.19) in point A. The average time of surgery was 2.78 (±0.64) hours, with an average blood loss of 240 (±48.6) ml. Four patients required a rhinoplasty in a secondary surgery. ConclusionThis technique shows a surgical approach with low morbidity, short surgery time, and low blood loss. It allows optimal resolution of severe hypoplasia of the middle third of the face with long-term stability. It avoids the use of grafts and osteosynthesis material. By not including the nasal pyramid in the osteotomy design, the size, position, and nasofrontal angle in patients with adequate facial balance is maintained. If nasal correction is necessary, a second surgery may be done. In cases of asymmetrical hypoplasia of the middle third, this osteotomy shows great versatility and can be done unilaterally and/or simultaneously combined with other distractions.

Asymmetric Cross-language Activation of Translations in Korean-English Bilinguals

This study tested the predictions of the Revised Hierarchical Model (RHM) and the Bilingual Interactive Activation Plus (BIA+) model through a translation recognition task in which low-intermediate Korean-English bilinguals decided whether the second word of a two-word sequence was the correct translation of the first. In the critical distractor conditions, the second word was not a correct translation of the first, but phonologically related to the first word (i.e., phonological neighbors), or phonologically related to the correct translation (i.e., translation neighbors). Results showed that the participants experienced interference for related distractors in both L2-L1 and L1-L2 translation directions. However, an interaction with distractor type was only found in the forward (L1 to L2) translation direction, with a larger interference effect for the translation neighbors. The results of the present study support and extend the predictions of the BIA+ model by showing nonselective phonological activation for different-script bilinguals, while also supporting the predictions of the RHM regarding translation asymmetry. We suggest previous assumptions regarding the mechanisms of the translation recognition task and interpretation of its data may be flawed, and propose a fundamental rethinking of these issues.

Time of presentation affects auditory distraction: Changing-state and deviant sounds disrupt similar working memory processes.

Four experiments tested conflicting predictions about which components of the serial-recall task are most sensitive to auditory distraction. Changing-state (Experiments 1a and 1b) and deviant distractor sounds (Experiments 2a and 2b) were presented in one of four different intervals of the serial-recall task: (1) during the first half of encoding, (2) during the second half of encoding, (3) during the first half of retention, or (4) during the second half of retention. According to the embedded-processes model, both types of distractors should interfere with the encoding and rehearsal of targets in the focus of attention. According to the duplex-mechanism account, changing-state distractors should interfere only with rehearsal, whereas deviant distractors should interfere only with encoding. Inconsistent with the latter view, changing-state and deviant distractor sounds interfered with both the encoding and the retention of the targets. Both types of auditory distraction were most pronounced during the second half of encoding when the increasing rehearsal demands had to be coordinated with the continuous updating of the rehearsal set. These findings suggest that the two types of distraction disrupt similar working memory mechanisms.

Are precues effective in proactively controlling taboo interference during speech production?

ABSTRACTThis research investigated whether precues engage proactive control to reduce emotional interference during speech production. A picture-word interference task required participants to name target pictures accompanied by taboo, negative, or neutral distractors. Proactive control was manipulated by presenting precues that signalled the type of distractor that would appear on the next trial. Experiment 1 included one block of trials with precues and one without, whereas Experiment 2 mixed precued and uncued trials. Consistent with previous research, picture naming was slowed in both experiments when distractors were taboo or negative compared to neutral, with the greatest slowing effect when distractors were taboo. Evidence that precues engaged proactive control to reduce interference from taboo (but not negative) distractors was found in Experiment 1. In contrast, mixing precued trials in Experiment 2 resulted in no taboo cueing benefit. These results suggest that item-level proactive control can be engaged under certain conditions to reduce taboo interference during speech production, findings that help to refine a role for cognitive control of distraction during speech production.

Polarity-dependent Effects of Biparietal Transcranial Direct Current Stimulation on the Interplay between Target Location and Distractor Saliency in Visual Attention.

Visual attention allows the allocation of limited neural processing resources to stimuli based on their behavioral priorities. The selection of task-relevant visual targets entails the processing of multiple competing stimuli and the suppression of distractors that may be either perceptually salient or perceptually similar to targets. The posterior parietal cortex controls the interaction between top-down (task-driven) and bottom-up (stimulus-driven) processes competing for attentional selection, as well as spatial distribution of attention. Here, we examined whether biparietal transcranial direct current stimulation (tDCS) would modulate the interaction between top-down and bottom-up processes in visual attention. Visual attention function was assessed with a visual discrimination task, in which a lateralized target was presented alone or together with a contralateral, similar or salient, distractor. The accuracy and RTs were measured before and during three stimulation sessions (sham, right anodal/left cathodal, left anodal/right cathodal). The analyses demonstrated (i) polarity-dependent effects of tDCS on the accuracy of target discrimination, but only when the target was presented with a similar distractor; (ii) the tDCS-triggered effects on the accuracy of discriminating targets, accompanied by a similar distractor, varied according to the target location; and (iii) overall detrimental effects of tDCS on RTs were observed, regardless of target location, distractor type, and polarity of the stimulation. We conclude that the observed polarity, distractor type, and target location-dependent effects of biparietal tDCS on the accuracy of target detection resulted from both a modulation of the interaction between top-down and bottom-up attentional processes and the interhemispheric competition mechanisms guiding attentional selection and spatial deployment of attention.

Management of metacarpal and phalangeal fractures with JESS fixator: A prospective study

The human hand architected to show an exceptional movements and is often a most vulnerable to various degree of injuries caused often by road traffic accidents and industrial accidents. Treatment of hand injuries involves in joint range improvement and redevelopment of coordinative movements. Joshi’s external stabilizing system (JESS) provides a stable skeletal environment with early tissue healing and immediate active and passive mobilization of the uninjured adjacent joints. This study designed to assess the efficacy of JESS in management of Hand injuries. Study includes 50 patients of both sexes and all age groups with open or close type of hand injuries. All the patients were allowed to complete clinical and radiological assessment before and after surgical procedure along with subsequent follow up. Various types of distractors (30%) were applied because majority fractures were intra-articular and in 18% cases basic and extended hand frames were used. Fixators was removed within 6 weeks and in 68% wounds were healed at that time of fixator removal. Swelling was commonly associated complications in 32% cases. The incidence of non-union and delayed union of fractures was 8%, 10% respectively. At the time of final follow up 62.8% metacarpophalangeal joints, 64% of interphalangeal joints, 63% of proximal metacarpophalangeal joints, 63.5% of distal metacarpophalangeal joints and 62% of wrist joints regained their normal movements. In 74% cases grip strength was remains normal. JESS is simple, modular and low expensive. It assists the surgeon in obtaining tissue stabilization, spontaneous revascularization and tissue expansion by gradual and controlled distraction.

Foraging through multiple target categories reveals the flexibility of visual working memory

A key assumption in the literature on visual attention is that templates, actively maintained in visual working memory (VWM), guide visual attention. An important question therefore involves the nature and capacity of VWM. According to load theories, more than one search template can be active at the same time and capacity is determined by the total load rather than a precise number of templates. By an alternative account only one search template can be active within visual working memory at any given time, while other templates are in an accessory state – but do not affect visual selection. We addressed this question by varying the number of targets and distractors in a visual foraging task for 40 targets among 40 distractors in two ways: 1) Fixed-distractor-number, involving two distractor types while target categories varied from one to four. 2) Fixed-color-number (7), so that if the target types were two, distractors types were five, while if target number increased to three, distractor types were four (etc.). The two accounts make differing predictions. Under the single-template account, we should expect large switch costs as target types increase to two, but switch-costs should not increase much as target types increase beyond two. Load accounts predict an approximately linear increase in switch costs with increased target type number. The results were that switch costs increased roughly linearly in both conditions, in line with load accounts. The results are discussed in light of recent proposals that working memory reflects lingering neural activity at various sites that operate on the stimuli in each case and findings showing neurally silent working memory representations.

Effects of the number of distractor types on attentional blink

Effects of the number of distractor types on attentional blink

The influence of affective state on exogenous attention to emotional distractors: behavioral and electrophysiological correlates

The interplay between exogenous attention to emotional distractors and the baseline affective state has not been well established yet. The present study aimed to explore this issue through behavioral measures and event-related potentials (ERPs). Participants (N = 30) completed a digit categorization task depicted over negative, positive or neutral distractor background pictures, while they experienced negative, positive and neutral affective states elicited by movie scenes. Behavioral results showed higher error rates and longer reaction times for negative distractors than for neutral and positive ones, irrespective of the current emotional state. Neural indices showed that the participants’ affective state modulated N1 amplitudes, irrespective of distractor type, while the emotional charge of distractors modulated N2, irrespective of the emotional state. Importantly, an interaction of state and distractor type was observed in LPP. These results demonstrate that exogenous attention to emotional distractors is independent from modulating effects of the emotional baseline state at early, automatic stages of processing. However, attention to emotional distractors and affective state interact at later latencies.

Information Processing of the Rorschach's Traumatic Content Index in Trauma-exposed Adults: An Event Related Potential (ERP) Study

PTSD elicits hypervigilance to trauma-related stimuli. Our novel research examined event-related potentials from Blood, Anatomy, and Morbid content derived from the Rorschach's traumatic content index (TCI). Participants included: 16 with PTSD, 24 trauma-exposed without PTSD (non-PTSD), and 16 non-traumatized Controls. P3 oddball paradigms were used with TCI-derived Distractors and neutral Targets/Standards. We predicted larger P3 amplitudes in the context of TCI-related Distractors among trauma-exposed participants. Significant interaction of Group and Distractor type was found for P3 amplitude. PTSD and non-PTSD groups exhibited larger P3 amplitudes from Blood and Anatomy Distractors, and attenuated amplitudes from Morbid; the reverse pattern was found among Controls. A late negative component was observed, denoting a significantly larger area under the curve (AUC) among the PTSD group for Anatomy and Blood Distractors. Larger AUC's were observed for Distractors among the PTSD group, and Targets among Controls. The findings concur with the neurocircuitry model of PTSD and suggest impairment in cerebral suppression of attention to stimuli that may have been perceptually primed with trauma.