Electrophysiological correlates of feature analysis during visual search

The influence of task-irrelevant color perception on flanker task performance: Insights from behavioral and ERP data

Perception of color as a task-relevant stimulus can affect cognition and behavior in the flanker task; however, it remains unclear whether it has the same impact when it is a task-irrelevant stimulus dimension. To this end, we applied four-letter flanker tasks with or without colored (red/blue) to 23 healthy young adults, while recording the event-related potentials (ERPs) and behavioral performance. The flanker task included four kinds of color types: non-color letter (NC), all color letter (AC), flanker color letter (FC), and target color letter (TC), each flanker task included congruent and incongruent conditions. The behavioral data demonstrated the classic conflict effect across all color types of flanker tasks in both reaction times (RTs) and accuracy, the significant interaction and main effect of color type factors were only observed in accuracy. The ERP results showed significant interaction between conflict factor (congruent, incongruent) and color type (NC, AC, FC, and TC), and the color type factor enhanced the fronto-central P2 (180-200 ms), descended the fronto-centro-parietal N2b (260-320 ms), and increased the fronto-central P3b (360-520 ms). The fronto-central P2 and the fronto-central P3b were larger for TC than NC, AC, and FC in the congruent condition, while the fronto-central P3b was smaller for NC than AC, FC, and TC in the incongruent condition. Furthermore, the fronto-centro-parietal N2b was decreased successively in NC, AC, FC, and TC in both congruent and incongruent conditions. Overall, our findings suggested that the task-irrelevant stimuli dimension of color can capture some attentional resources and is affected by the location of color (target/flanker) and the type of task trial (congruent/incongruent) in the flanker task.

Attentional templates for target features versus locations

Visual search is guided by visual working memory representations (i.e., attentional templates) that are activated prior to search and contain target-defining features (e.g., color). In the present study, we tested whether attentional templates can also contain spatial target properties (knowing where to look for) and whether attentional selection guided by such feature-specific templates is equally efficient than selection that is based on feature-specific templates (knowing what to look for). In every trial, search displays were either preceded by semantic color or location cues, indicating the upcoming target color or location, respectively. Qualitative differences between feature- and location-based template guidance were substantiated in terms of selection efficiency in low-load (one target color/location) versus high-load trials (two target colors/locations). Behavioral and electrophysiological (N2pc) measures of target selection speed and accuracy were combined for converging evidence. In line with previous studies, we found that color search was highly efficient, even under high-low conditions, when multiple attentional templates were activated to guide attentional selection in a spatially global fashion. Importantly, results in the location task almost perfectly mirrored the findings of the color task, suggesting that multiple templates for different target locations were activated concurrently when two possible target locations were task relevant. Our findings align with accounts that assume a common neuronal network during preparation for location and color search, but regard spatial and feature-based selection mechanisms as independent.

N1 and LNC reveal the differential electrophysiological signatures of functional and hedonic images processing

In the process of creative sentence or phrase utilization, novel and appropriate evaluations cause the different brain responses observed in event-related potentials: the N400 reflects the novelty evaluation, whereas a late negative component marks appropriate processing. Do we have similar brain reactions in image perception when we rapidly browse pictures of objects with different novelty, functional/appropriate, and hedonic value? To explore this question, participants were presented with four novel object images with high or low functional and hedonic properties, as well as the ordinary product images, with the instruction to attentively observe and understand each image. We found a clear dissociation between processing of novelty and functional value: novelty objects produced negative deflections in the N2-N400 time window relative to the ordinary object images, whereas images with high functional value elicited a larger N2 and late negative waves (LNC) resembling the late component found for the appropriate phrases. Object images with high hedonic value, however, were associated with earlier aesthetic preference reflected in smaller N1 amplitudes, but failed to elicit a LNC effect. We therefore conclude that the processing of novelty, functional, and hedonic value are dissociation, and the perception of hedonic value is earlier (N1) than the novelty processing (N400) and the verification of functional value (LNC).

The neural basis of attentional selection in goal-directed memory retrieval

Goal-directed memory reactivation involves retrieving the most relevant information for the current behavioral goal. Previous research has linked this process to activations in the fronto-parietal network, but the underlying neurocognitive mechanism remains poorly understood. The current electroencephalogram (EEG) study explores attentional selection as a possible mechanism supporting goal-directed retrieval. We designed a long-term memory experiment containing three phases. First, participants learned associations between objects and two screen locations. In a following phase, we changed the relevance of some locations (selective cue condition) to simulate goal-directed retrieval. We also introduced a control condition, in which the original associations remained unchanged (neutral cue condition). Behavior performance measured during the final retrieval phase revealed faster and more confident responses in the selective vs. neutral condition. At the EEG level, we found significant differences in decoding accuracy, with above-chance effects in the selective cue condition but not in the neutral cue condition. Additionally, we observed a stronger posterior contralateral negativity and lateralized alpha power in the selective cue condition. Overall, these results suggest that attentional selection enhances task-relevant information accessibility, emphasizing its role in goal-directed memory retrieval.

Influence of presentation duration on filtering of irrelevant stimuli in visual working memory

In environments teeming with distractions, the ability to selectively focus on relevant information is crucial for advanced cognitive processing. Existing research using event-related potential (ERP) technology has shown active suppression of irrelevant stimuli during the consolidation phase of visual working memory (VWM). In previous studies, participants have always been given sufficient time to consolidate VWM, while suppressing distracting information. However, it remains unclear whether the suppression of irrelevant distractors requires continuous effort throughout their presence or whether this suppression is only necessary after the consolidation of task-relevant information. To address this question, our study examines whether distractor suppression is necessary in scenarios where consolidation time is limited. This research investigates the effect of varying presentation durations on the filtering of distractors in VWM. We tasked participants with memorizing two color stimuli and ignoring four distractors, presented for either 50 ms or 200 ms. Using ERP technology, we discovered that the distractor-induced distractor positivity (PD) amplitude is larger during longer presentation durations compared to shorter ones. These findings underscore the significant impact of presentation duration on the efficacy of distractor suppression in VWM, as prolonged exposure results in a stronger suppression effect on distractors. This study sheds light on the temporal dynamics of attention and memory, emphasizing the critical role of stimulus timing in cognitive tasks. These findings provide valuable insights into the mechanisms underlying VWM and have significant implications for models of attention and memory.

Visual selective attention in individuals with age-related hearing loss

Evidence from epidemiological studies suggests that hearing loss is associated with an accelerated decline in cognitive function, but the underlying pathophysiological mechanism remains poorly understood. Studies using auditory tasks have suggested that degraded auditory input increases the cognitive load for auditory perceptual processing and thereby reduces the resources available for other cognitive tasks. Attention-related networks are among the systems overrecruited to support degraded auditory perception, but it is unclear how they function when no excessive recruitment of cognitive resources for auditory processing is needed. Here, we implemented an EEG study using a nonauditory visual attentional selection task in 30 individuals with age-related hearing loss (ARHLs, 60-73 years) and compared them with aged (N = 30, 60-70 years) and young (N = 35, 22-29 years) normal-hearing controls. Compared with their normal-hearing peers, ARHLs demonstrated a significant amplitude reduction for the posterior contralateral N2 component, which is a well-validated index of the allocation of selective visual attention, despite the comparable behavioral performance. Furthermore, the amplitudes were observed to correlate significantly with hearing acuities (pure tone audiometry thresholds) and higher-order hearing abilities (speech-in-noise thresholds) in aged individuals. The target-elicited alpha lateralization, another mechanism of visuospatial attention, demonstrated in control groups was not observed in ARHLs. Although behavioral performance is comparable, the significant decrease in N2pc amplitude in ARHLs provides neurophysiologic evidence that may suggest a visual attentional deficit in ARHLs even without extra-recruitment of cognitive resources by auditory processing. It supports the hypothesis that constant degraded auditory input in ARHLs has an adverse impact on the function of cognitive control systems, which is a possible mechanism mediating the relationship between hearing loss and cognitive decline.

Conflicting Sensory Information Sharpens the Neural Representations of Early Selective Visuospatial Attention

Adaptive behaviors require the ability to resolve conflicting information caused by the processing of incompatible sensory inputs. Prominent theories of attention have posited that early selective attention helps mitigate cognitive interference caused by conflicting sensory information by facilitating the processing of task-relevant sensory inputs and filtering out behaviorally irrelevant information. Surprisingly, many recent studies that investigated the role of early selective attention on conflict mitigation have failed to provide positive evidence. Here, we examined changes in the selectivity of early visuospatial attention in male and female human subjects performing an attention-cueing Eriksen flanker task, where they discriminated the shape of a visual target surrounded by congruent or incongruent distractors. We used the inverted encoding model to reconstruct spatial representations of visual selective attention from the topographical patterns of amplitude modulations in alpha band oscillations in scalp EEG (∼8-12 Hz). We found that the fidelity of the alpha-based spatial reconstruction was significantly higher in the incongruent compared with the congruent condition. Importantly, these conflict-related modulations in the reconstruction fidelity occurred at a much earlier time window than those of the lateralized posterior event-related potentials associated with target selection and distractor suppression processes, as well as conflict-related modulations in the frontocentral negative-going wave and midline-frontal theta oscillations (∼3-7 Hz), thought to track executive control functions. Taken together, our data suggest that conflict resolution is supported by the cascade of neural processes underlying early selective visuospatial attention and frontal executive functions that unfold over time.

Tracking the brain signature of (mis)spelled logotypes via letter transpositions and replacements

All leading models of visual word recognition assume a hierarchical process that progressively converts the visual input into abstract letter and word representations. However, the results from recent behavioral studies suggest that the mental representations of words with a highly consistent visual format, such as logotypes, may comprise not only purely abstract information but also perceptual information. This hypothesis would explain why participants often misperceive transposed-letter misspellings with the original base words to a larger degree in logotypes (e.g., SASMUNG, but not SARVUNG, is perceived as SAMSUNG) than in common words. The present experiment examined the electrophysiological signature behind the identification of correctly spelled and misspelled logotypes (via letter transposition or replacement) in an ERP go/no-go semantic categorization experiment. Results showed that N400 amplitudes for transposed-letter misspelled logotypes (SASMUNG) and intact logotypes (SAMSUNG) did not differ significantly across various time windows (until 600 ms), whereas replacement-letter misspelled logotypes (SARVUNG) yielded consistently larger N400 amplitudes. These findings reveal that the mental representations of logotypes are particularly resistant to minor orthographic changes, which has important theoretical and applied (e.g., marketing) implications.

Are Deaf College Students More Sensitive to Unfair Information? Evidence from an ERP Study

To better understand the individual differences in fairness, we used event-related potentials (ERPs) to explore the fairness characteristics of deaf college students through the ultimatum game task. Behaviorally, the significant main effect of the proposal type was found, which meant both deaf and hearing college students showed a lower acceptance rate for the more unfair proposal. Interestingly, we found a significant interaction between group and proposal type in the early stage (N1). Moreover, in the deaf college group, N1 (induced by moderately and very unfair proposals) was significantly larger than that of fair proposals. However, we found that deaf college students had smaller amplitudes on P2 and P3 than hearing college students. These results suggested that deaf college students might pursue more equity strongly so they are more sensitive to unfair information in the early stage. In a word, we should provide more fair allocations for deaf college students in our harmonious society.

Human brain dynamics dissociate early perceptual and late motor-related stages of affordance processing

Affordances, the opportunities for action offered by the environment to an agent, are vital for meaningful behaviour and exist in every interaction with the environment. There is an ongoing debate in the field about whether the perception of affordances is an automated process. Some studies suggest that affordance perception is an automated process that is independent from the visual context and bodily interaction with the environment, whereas others argue that it is modulated by the visual and motor context in which affordances are perceived. The present paper aims to resolve this debate by examining affordance automaticity from the perspective of sensorimotor time windows. To investigate the impact of different forms of bodily interactions with an environment, that is, the movement context (physical vs. joystick movement), we replicated a previous study on affordance perception in which participants actively moved through differently wide doors in an immersive 3D virtual environment. In the present study, we displayed the same environment on a 2D screen with participants moving through doors of different widths using the keys on a standard keyboard. We compared components of the event-related potential (ERP) from the continuously recorded electroencephalogram (EEG) that were previously reported to be related to affordance perception of architectural transitions (passable and impassable doors). Comparing early sensory and later motor-related ERPs, our study replicated ERPs reflecting early affordance perception but found differences in later motor-related components. These results indicate a shift from automated perception of affordances during early sensorimotor time windows to movement context dependence of affordance perception at later stages, suggesting that affordance perception is a dynamic and flexible process that changes over sensorimotor stages.

Camouflage patterning modulates neural signatures of attention and decision-making

Many animals rely on visual camouflage to avoid detection and increase their chances of survival. Edge disruption is commonly seen in the natural world, with animals evolving high-contrast markings that are incongruent with their real body outline in order to avoid recognition. While many studies have investigated how camouflage properties influence viewer performance and eye movement in predation search tasks, researchers in the field have yet to consider how camouflage may directly modulate visual attention and object processing. To examine how disruptive coloration modulates attention, we use a visual object recognition model to quantify object saliency. We determine if object saliency is predictive of human behavioural performance and subjective certainty, as well as neural signatures of attention and decision-making. We show that increasing edge disruption not only reduces detection and identification performance but is also associated with a dampening of neurophysiological signatures of attentional filtering. Increased self-reported certainty regarding decisions corresponds with neurophysiological signatures of evidence accumulation and decision-making. In summary, we have demonstrated a potential mechanism by which edge disruption increases the evolutionary fitness of animals by reducing the brain's ability to distinguish signal from noise, and hence to detect and identify the camouflaged animal.

Tracking the Misallocation and Reallocation of Spatial Attention toward Auditory Stimuli

Completely ignoring a salient distractor presented concurrently with a target is difficult, and sometimes attention is involuntarily attracted to the distractor's location (attentional capture). Employing the N2ac component as a marker of attention allocation toward sounds, in this study we investigate the spatiotemporal dynamics of auditory attention across two experiments. Human participants (male and female) performed an auditory search task, where the target was accompanied by a distractor in two-third of the trials. For a distractor more salient than the target (Experiment 1), we observe not only a distractor N2ac (indicating attentional capture) but the full chain of attentional dynamics implied by the notion of attentional capture, namely, (1) the distractor captures attention before the target is attended, (2) allocation of attention to the target is delayed by distractor presence, and (3) the target is attended after the distractor. Conversely, for a distractor less salient than the target (Experiment 2), although responses were delayed, no attentional capture was observed. Together, these findings reveal two types of spatial attentional dynamics in the auditory modality (distraction with and without attentional capture).

Temporal dynamics of spatial attentional biases toward weight-related words among females with weight dissatisfaction

Attentional bias toward weight-related stimuli plays a crucial role in the development and maintenance of body image disturbances. However, the temporal dynamics of attentional biases responsible for the previously reported behavioral effects caused by the task-irrelevant but spatial-relevant weight-related stimuli presented in the peripheral visual field among females with high weight dissatisfaction (HWD) remain unclear. The present study combined the modified dot-probe task and event-related potentials to explore the temporal dynamics of spatial attentional biases toward weight-related words among females with HWD. The results showed significantly larger N2pc amplitudes were elicited by fat-related and thin-related words than neutral words only in the HWD group. Moreover, only fat-related words elicited a significant PD for the HWD group, and the PD amplitudes were larger in the HWD group than in the control group. These findings revealed that weight-related words initially captured spatial allocation among females with HWD, and then fat-related words were actively suppressed after the initial capturing.

Chronic academic stress improves attentional control: Behavioral and electrophysiological evidence

Background

Detecting and responding to target objects in the visual environment is a key factor in goal-directed behavior. Exposure to chronic stress often results in alterations of prefrontal cortex (PFC) function, which may impact PFC-dependent selective attention process. This study aimed to investigate the effect of chronic academic stress on attentional control process.

Method

Both the stress group and the control group performed an arrow-based version of the Eriksen Flanker task. Event-related potentials (ERP) were recorded while the participants performed the task.

Results

The behavioural results exhibited decreased Flanker RT effect for the stress group compared to the control group, suggesting a reduced interference under stress. The ERP results showed that stress group showed decreased frontal N2 but increased early P3 and late P3/LPC activities compared to the control group. These results suggest reduced conflict monitoring but increased conflict resolution process under stress.

Conclusions

The chronic academic stress improves attentional control by reducing the conflict monitoring and enhancing conflict resolution processes.

An electrophysiological investigation of referential communication

A key aspect of linguistic communication involves semantic reference to objects. Presently, we investigate neural responses at objects when reference is disrupted, e.g., "The connoisseur tasted *that wine"… vs. "…*that roof…" Without any previous linguistic context or visual gesture, use of the demonstrative determiner "that" renders interpretation at the noun as incoherent. This incoherence is not based on knowledge of how the world plausibly works but instead is based on grammatical rules of reference. Whereas Event-Related Potential (ERP) responses to sentences such as "The connoisseur tasted the wine …" vs. "the roof" would result in an N400 effect, it is unclear what to expect for doubly incoherent "…*that roof…". Results revealed an N400 effect, as expected, preceded by a P200 component (instead of predicted P600 effect). These independent ERP components at the doubly violated condition support the notion that semantic interpretation can be partitioned into grammatical vs. contextual constructs.

Effects of peer victimization on cortical processing of social-evaluative stress in patients with major depressive disorder

Peer victimization contributes to the development of major depressive disorders (MDDs). While previous studies reported differentiated peripheral physiological responses in peer-victimized individuals with depression, little is known about potential alterations of cortical event-related potentials (ERPs) in response to social stimuli in depressive patients with a history of peer victimization. Using a social condition paradigm, the present study examined whether peer victimization alters conditioned cortical responses to potentially threatening social stimuli in MDD patients and healthy controls. In the task, we studied ERPs to conditioned stimuli (CSs), i.e. still images of faces, that were coupled to unconditioned socially negative and neutral evaluative video statements. Peer victimization was related to more pronounced P100 amplitudes in reaction to negative and neutral CSs. Attenuated P200 amplitudes in peer-victimized individuals were found in response to negative CSs. Cortical responses to CSs were not influenced by a diagnosis of MDD. The results suggest altered responsiveness to interpersonal information in peer-victimized individuals. Facilitated early processing of social threat indicators may prevent peer-victimized individuals from adaptive responses to social cues, increasing their vulnerability for depression.

Multimodal fusion for anticipating human decision performance

Anticipating human decisions while performing complex tasks remains a formidable challenge. This study proposes a multimodal machine-learning approach that leverages image features and electroencephalography (EEG) data to predict human response correctness in a demanding visual searching task. Notably, we extract a novel set of image features pertaining to object relationships using the Segment Anything Model (SAM), which enhances prediction accuracy compared to traditional features. Additionally, our approach effectively utilizes a combination of EEG signals and image features to streamline the feature set required for the Random Forest Classifier (RFC) while maintaining high accuracy. The findings of this research hold substantial potential for developing advanced fault alert systems, particularly in critical decision-making environments such as the medical and defence sectors.

Exploration of the influence of the quantification method and reference scheme on feedback-related negativity and standardized measurement error of feedback-related negativity amplitudes in a trust game

Various approaches have been taken over the years to quantify event-related potential (ERP) responses and these approaches may vary in their utility connecting empirical research and scientific claims. In this work we compared different quantification methods as well as the influence of three reference methods (linked mastoids, average reference, and current source density) on the resulting ERP amplitude. We use the experimental effects and effect sizes (Cohen's d) to evaluate the different methodological variants and we calculate intraclass correlation coefficients (ICC). In addition, the bootstrapped standard error of the means (SME, Luck et al., 2021), which was recently suggested as a quality criterion for ERP research, is used for this purpose. Our example for an ERP is the feedback-related negativity (FRN) to feedback about trustee behavior in a trust game with participants in the trustor position. We found that the quantification methods concerning the FRN influenced the absolute value of condition effects in the experimental paradigm. Yet, the patterns of effects were detected by all chosen methods, except for the 'individual difference wave'-based peak window approach. In addition, our findings stress the importance of checking the reference electrodes concerning effects of the experimental conditions. Furthermore, interactions of topographical distribution and reference choice should be considered. Finally, we were able to show that the SME is lower for more datapoints that are given in the quantification period of the FRN, and higher for more negative FRN amplitudes. These biases may lead to divergence of SME and effect size detection. Therefore, if the SME was used to compare different processing choices one should consider controlling for these important aspects of the data and possibly include other quality criteria like effect sizes.

When experience with scenes foils attentional orienting: ERP evidence against flexible target-context mapping in visual search

Visual search is speeded when a target is repeatedly presented in an invariant scene context of nontargets (contextual cueing), demonstrating observers' capability for using statistical long-term memory (LTM) to make predictions about upcoming sensory events, thus improving attentional orienting. In the current study, we investigated whether expectations arising from individual, learned environmental structures can encompass multiple target locations. We recorded event-related potentials (ERPs) while participants performed a contextual cueing search task with repeated and non-repeated spatial item configurations. Notably, a given search display could be associated with either a single target location (standard contextual cueing) or two possible target locations. Our result showed that LTM-guided attention was always limited to only one target position in single- but also in the dual-target displays, as evidenced by expedited reaction times (RTs) and enhanced N1pc and N2pc deflections contralateral to one ("dominant") target of up to two repeating target locations. This contrasts with the processing of non-learned ("minor") target positions (in dual-target displays), which revealed slowed RTs alongside an initial N1pc "misguidance" signal that then vanished in the subsequent N2pc. This RT slowing was accompanied by enhanced N200 and N400 waveforms over fronto-central electrodes, suggesting that control mechanisms regulate the competition between dominant and minor targets. Our study thus reveals a dissociation in processing dominant versus minor targets: While LTM templates guide attention to dominant targets, minor targets necessitate control processes to overcome the automatic bias towards previously learned, dominant target locations.

Early Electrophysiological Correlates of Perceptual Consciousness Are Affected by Both Exogenous and Endogenous Attention

It has been proposed that visual awareness negativity (VAN), which is an early ERP component, constitutes a neural correlate of visual consciousness that is independent of perceptual and cognitive mechanisms. In the present study, we investigated whether VAN is indeed a specific marker of phenomenal awareness or rather reflects the involvement of attention. To this end, we reanalyzed data collected in a previously published EEG experiment in which awareness of visual stimuli and two aspects that define attentional involvement, namely, the inherent saliency and task relevance of a stimulus, were manipulated orthogonally. During the experimental procedure, participants (n = 41) were presented with images of faces that were backward-masked or unmasked, fearful or neutral, and defined as task-relevant targets or task-irrelevant distractors. Single-trial ERP analysis revealed that VAN was highly dependent on attentional manipulations in the early time window (140-200 msec), up to the point that the effect of awareness was not observed for attentionally irrelevant stimuli (i.e., neutral faces presented as distractors). In the late time window (200-350 msec), VAN was present in all attentional conditions, but its amplitude was significantly higher in response to fearful faces and task-relevant face images than in response to neutral ones and task-irrelevant ones, respectively. In conclusion, we demonstrate that the amplitude of VAN is highly dependent on both exogenous (stimulus saliency) and endogenous attention (task requirements). Our results challenge the view that VAN constitutes an attention-independent correlate of phenomenal awareness.

Effects of different speed-accuracy instructions on perception in psychology experiments: evidence from event-related potential and oscillation

Introduction

In cognitive behavioral experiments, we often asked participants to make judgments within a deadline. However, the most common instruction of "do the task quickly and accurately" does not highlight the importance of the balance between being fast and accurate.

Methods

Our research aimed to explore how instructions about speed or accuracy affect perceptual process, focus on event-related potentials (ERPs) and event-related oscillations (EROs) of two brain responses for visual stimuli, known as P1 and N1. Additionally, we compared the conventional analysis approach with principal component analysis (PCA) based methods to analyze P1 and N1 ERP amplitude and ERO power.

Results

The results showed that individuals instructed to respond quickly had lower P1 amplitude and alpha ERO than those who prioritized accuracy, using the PCA-based approach. However, these two groups had no differences between groups in the N1 theta band using both methods. The traditional time-frequency analysis method could not detect any ERP or ERO distinctions between groups due to limitations in detecting specific components in time or frequency domains. That means PCA is effective in separating these components.

Discussion

Our findings indicate that the instructions given regarding speed and accuracy impact perceptual process of subjects during cognitive behavioral experiments. We suggest that future researchers should choose their instructions carefully, considering the purpose of study.

How and when social evaluative feedback is processed in the brain: A systematic review on ERP studies

Social evaluative feedback informs the receiver of the other's views, which may contain judgments of personality-related traits and/or the level of likability. Such kinds of social evaluative feedback are of particular importance to humans. Event-related potentials (ERPs) can directly measure where in the processing stream feedback valence, expectancy, or contextual relevance modulate information processing. This review provides an overview and systematization of studies and early, mid-latency, and late ERP effects. Early effects were inconsistently reported for all factors. Feedback valence effects are more consistently reported for specific mid-latency ERPs (Reward Positivity, RewP, and Early Posterior Negativity, EPN) and late positivities (P3 and Late Positive Potential, LPP). Unexpected feedback consistently increased the Feedback Related Negativity (FRN) and, less consistently, decreased P3 amplitudes. Contextual relevance of the sender (e.g., human vs computer sender) or self-relatedness increased mid-latency to late ERPs. Interactions between valence and other factors were less often found, arising during mid-latency stages, where most consistent interactions showed larger EPN and P3 amplitude differences for valent feedback in a more relevant context. The ERP findings highlight that social evaluative feedback is consistently differentiated during mid-latency processing stages. The review discusses the relevance of findings, possible shortcomings of different experimental designs, and open questions. Furthermore, we suggest concrete venues for future research.

Relative saliency affects attentional capture and suppression of color and face singleton distractors: evidence from event-related potential studies

Prior research has yet to fully elucidate the impact of varying relative saliency between target and distractor on attentional capture and suppression, along with their underlying neural mechanisms, especially when social (e.g. face) and perceptual (e.g. color) information interchangeably serve as singleton targets or distractors, competing for attention in a search array. Here, we employed an additional singleton paradigm to investigate the effects of relative saliency on attentional capture (as assessed by N2pc) and suppression (as assessed by PD) of color or face singleton distractors in a visual search task by recording event-related potentials. We found that face singleton distractors with higher relative saliency induced stronger attentional processing. Furthermore, enhancing the physical salience of colors using a bold color ring could enhance attentional processing toward color singleton distractors. Reducing the physical salience of facial stimuli by blurring weakened attentional processing toward face singleton distractors; however, blurring enhanced attentional processing toward color singleton distractors because of the change in relative saliency. In conclusion, the attentional processes of singleton distractors are affected by their relative saliency to singleton targets, with higher relative saliency of singleton distractors resulting in stronger attentional capture and suppression; faces, however, exhibit some specificity in attentional capture and suppression due to high social saliency.

Different neural mechanisms for nonsalient trained stimuli and physically salient stimuli in visual processing

Previous studies have shown that nonsalient trained stimuli could capture attention and would be actively suppressed when served as distractors. However, it was unclear whether nonsalient trained stimuli and physically salient stimuli operate through the same attentional neural mechanism. In the current study, we investigated this question by recording event-related potentials (ERPs) of searching for the two stimuli separately after matching the difficulty. The present results provided additional evidence for the function of the suppression in that it may terminate a shift of attention. For the N1 component, the nonsalient trained stimuli had a shorter latency and larger amplitude than the physically salient stimuli whether presented as targets or distractors. It indicated that the nonsalient trained stimuli had an earlier sensory processing and greater visual attention orienting. The N2 posterior-contralateral (N2pc) amplitude of the physically salient target was larger than the nonsalient trained target. This suggested that physically salient stimuli had a stronger ability to capture attention. However, when they presented as distractors, only the nonsalient trained stimuli could elicit the PD component. Therefore, active suppression of the physically salient stimuli was more difficult than the nonsalient trained stimulus with the same difficulty. For the P3 component, the amplitude of the physically salient stimuli was larger than that of the nonsalient trained stimuli, both as targets and distractors, which indicated that the top-down controlled process of outcome evaluation for the salient triangle was stronger. Overall, these results suggested that they were processed via different neural mechanisms in the early sensory processing, attentional selection, active suppression, and the outcome-evaluation process.

Fixation-related potentials during mobile map assisted navigation in the real world: The effect of landmark visualization style

An often-proposed enhancement for mobile maps to aid assisted navigation is the presentation of landmark information, yet understanding of the manner in which they should be displayed is limited. In this study, we investigated whether the visualization of landmarks as 3D map symbols with either an abstract or realistic style influenced the subsequent processing of those landmarks during route navigation. We utilized a real-world mobile electroencephalography approach to this question by combining several tools developed to overcome the challenges typically encountered in real-world neuroscience research. We coregistered eye-movement and EEG recordings from 45 participants as they navigated through a real-world environment using a mobile map. Analyses of fixation event-related potentials revealed that the amplitude of the parietal P200 component was enhanced when participants fixated landmarks in the real world that were visualized on the mobile map in a realistic style, and that frontal P200 latencies were prolonged for landmarks depicted in either a realistic or abstract style compared with features of the environment that were not presented on the map, but only for the male participants. In contrast, we did not observe any significant effects of landmark visualization style on visual P1-N1 peaks or the parietal late positive component. Overall, the findings indicate that the cognitive matching process between landmarks seen in the environment and those previously seen on a map is facilitated by more realistic map display, while low-level perceptual processing of landmarks and recall of associated information are unaffected by map visualization style.

The cognitive tasks and event-related potentials associated childhood adversity: A systematic review

In this systematic review, 18 articles met inclusion criteria to be qualitatively analyzed for converging evidence of brain activity, measured using event-related potential (ERP), related to retrospectively reported childhood adversity/trauma. Using the PRISMA guidelines for systematic reviews, 917 articles were assessed for inclusion and were filtered using study parameters. The most common ERP components listed in the literature were P100, N170, N200, P200, P300, ERN, and LPP. We discuss levels of evidence for changed brain activity, each ERP component, and the tasks used to evoke them. The Childhood Trauma Questionnaire was found to be the most commonly cited measure. We note the need to assess the duration and intensity of childhood adversity/trauma measurements in the strengths and limitations of the reported childhood adversity/trauma measurements. No concrete converging evidence was found to support a relationship between ERP-measured brain activity and retrospectively reported childhood adversity/trauma. Thus, a discussion of limitations and future directions for this field of research is presented.

Category-based attention facilitates memory search

We often need to decide whether the object we look at is also the object we look for. When we look for one specific object, this process can be facilitated by feature-based attention. However, when we look for many objects at the same time (e.g., the products on our shopping list) such a strategy may no longer be possible, as research has shown that we can actively prepare to detect only one or two objects at a time. Therefore, looking for multiple objects additionally requires long-term memory search, slowing down decision making. Interestingly, however, previous research has shown that distractor objects can be efficiently rejected during memory search when they are from a different category than the items in the memory set. Here, using EEG, we show that this efficiency is supported by top-down attention at the category level. In Experiment 1, human participants (both sexes) performed a memory search task on individually presented objects from different categories, most of which were distractors. We observed category-level attentional modulation of distractor processing from ∼150 ms after stimulus onset, expressed both as an evoked response modulation and as an increase in decoding accuracy of same-category distractors. In Experiment 2, memory search was performed on two concurrently presented objects. When both objects were distractors, spatial attention (indexed by the N2pc component) was directed to the object that was of the same category as the objects in the memory set. Together, these results demonstrate how top-down attention can facilitate memory search.Significance statement When we are in the supermarket, we repeatedly decide whether a product we look at (e.g., a banana) is on our memorized shopping list (e.g., apples, oranges, kiwis). This requires searching our memory, which takes time. However, when the product is of an entirely different category (e.g., dairy instead of fruit), the decision can be made quickly. Here, we used EEG to show that this between-category advantage in memory search tasks is supported by top-down attentional modulation of visual processing: The visual response evoked by distractor objects was modulated by category membership, and spatial attention was quickly directed to the location of within-category (vs. between-category) distractors. These results demonstrate a close link between attention and memory.

The effects of stress on reward responsiveness: a systematic review and preliminary meta-analysis of the event-related potential literature

Exposure to stressful events is associated with a range of negative physical and mental health outcomes, including depression. It is critical to understand the mechanisms through which stress impacts mental health to identify promising targets for prevention and intervention efforts. Low-reward responsiveness is thought to be a mechanism of effects of stress on negative health outcomes and can be reliably measured at the neurophysiological level by using event-related potentials (ERPs), such as the reward positivity (RewP) component. The goal of this systematic review and preliminary meta-analysis was to examine evidence of associations between stress and alterations in reward responsiveness measured using ERPs. Through a systematic review of the literature, 23 studies examining the effects of laboratory-induced stressors and naturalistic stressors or perceived stress on reward responsiveness met study criteria, 13 of which were included in the meta-analysis. Most studies were conducted in undergraduate and community samples, with three selected for specific conditions, and primarily in adults. The systematic review supported evidence of associations between laboratory-induced stressors and blunted reward responsiveness as measured by the RewP but there were more mixed results when considering direct associations between naturalistic stressors/perceived stress and reward-related ERPs. Given that all studies examined the RewP, the meta-analysis focused on this component and indicated that there was a weak, nonsignificant negative association between stress and RewP. Results emphasize the complex nature of relations between stress and reward-related ERPs and the need to consider alternative models in future research. We also provide reporting recommendations for ERP researchers to facilitate future meta-analyses.

Event-related potential correlates of implicit processing of own- and other-race faces in children

Human adults typically experience difficulties in recognizing and discriminating individual faces belonging to racial groups other than their own. The origin of this "other-race" effect is set in infancy, but the understanding of its developmental course is fragmented. We aimed to access the mechanisms of the other-race effect in childhood by unraveling the neural time course of own- and other-race face processing during a masked priming paradigm. White 6- and 7-year-old children (N = 19) categorized fully visible Asian (other-race) or White (own-race) target faces according to gender. Target faces were preceded by masked same-identity or different-identity prime faces, matching the target for race and gender. We showed an early priming effect on the N100 component, with larger amplitude to different-face pairs than to same-face pairs, and a later race effect on the N200 component, with larger amplitude to own-race face pairs than to other-race face pairs. Critically, race did not interact with priming at any processing stage (P100, N100, P200, N200, or P300). Our results suggest that race could have a temporally limited impact on face processing and that the implicit and unconscious identity processing of own- and other-race faces could be similar in 6- and 7-year-olds, depicting an immature other-race effect during childhood.

Terms of debate: Consensus definitions to guide the scientific discourse on visual distraction

Hypothesis-driven research rests on clearly articulated scientific theories. The building blocks for communicating these theories are scientific terms. Obviously, communication - and thus, scientific progress - is hampered if the meaning of these terms varies idiosyncratically across (sub)fields and even across individual researchers within the same subfield. We have formed an international group of experts representing various theoretical stances with the goal to homogenize the use of the terms that are most relevant to fundamental research on visual distraction in visual search. Our discussions revealed striking heterogeneity and we had to invest much time and effort to increase our mutual understanding of each other's use of central terms, which turned out to be strongly related to our respective theoretical positions. We present the outcomes of these discussions in a glossary and provide some context in several essays. Specifically, we explicate how central terms are used in the distraction literature and consensually sharpen their definitions in order to enable communication across theoretical standpoints. Where applicable, we also explain how the respective constructs can be measured. We believe that this novel type of adversarial collaboration can serve as a model for other fields of psychological research that strive to build a solid groundwork for theorizing and communicating by establishing a common language. For the field of visual distraction, the present paper should facilitate communication across theoretical standpoints and may serve as an introduction and reference text for newcomers.

A further specification of the effects of font emphasis on reading comprehension: Evidence from event-related potentials and neural oscillations

The attention hypothesis, which assumes that font emphasis captures readers' attention, is usually used to explain the mechanism by which such emphasis operates. This study further delineates the attention hypothesis by investigating the ways in which font emphasis captures attention and its effects on the integration of emphasized information into the previous context. We computed event-related potentials and frequency band-specific electroencephalographic power changes occurring while participants read sentences containing critical words that were either emphasized (i.e., displayed in a color different from the other words in the sentence) or not (i.e., shown in the same color as the rest of the sentence) and semantically congruent with prior words or not. The results showed that the emphasized words (as compared to control words) elicited a reduced N1 and increased P2, indicating that font emphasis reduced familiarity-based visuo-orthographic processing and instead increased controlled attentional processing. We also observed greater P300 and power decreases in the alpha and beta frequency range in response to critical words in the emphasized condition, suggesting that font emphasis enhances focal attention to promote a fuller integration of information into the sentence context. Furthermore, relative to the control condition, the emphasized condition induced delta and theta power increases for the incongruent words. These results suggest that font emphasis increases the efficiency of glyph processing, which facilitates lexical access.

Uncovering the underlying factors of ERP changes in the cyberball paradigm: A systematic review investigating the impact of ostracism and paradigm characteristics

The Cyberball is the most commonly employed paradigm for the investigation of the effects of social exclusion, also called ostracism. The analysis of event-related potentials (ERPs), short-term stimulus-induced fluctuations in the EEG signal, has been employed for the identification of time-sensitive neural responses to ostracism-related information. Changes in ERPs during the Cyberball are normally attributed to the effect of ostracism, but it has been argued that characteristics of the paradigm, not ostracism, are the driving force for these changes. To elucidate the origin of the ERP changes in the Cyberball, we systematically reviewed the Cyberball-ERP literature of healthy, adult populations, and evaluated whether the social context of ostracism or characteristics of the paradigm are better suited for the explanation of the found results. Our results show that for many components no clear origin can be identified, but that expectancy violations, not ostracism, best explains the results of the P3 complex. Future research should therefore also employ other paradigms for the research into the effects of ostracism on ERPs.

Age-related hearing loss associated with differences in the neural correlates of feature binding in visual working memory

The underlying neural mechanisms underpinning the association between age-related hearing loss (ARHL) and dementia remain unclear. A limitation has been the lack of functional neuroimaging studies in ARHL cohorts to help clarify this relationship. In the present study, we investigated the neural correlates of feature binding in visual working memory with ARHL (controls = 14, mild HL = 21, and moderate or greater HL = 23). Participants completed a visual change detection task assessing feature binding while their neural activity was synchronously recorded via high-density electroencephalography. There was no difference in accuracy scores for ARHL groups compared to controls. There was increased electrophysiological activity in those with ARHL, particularly in components indexing the earlier stages of visual cognitive processing. This activity was more pronounced with more severe ARHL and was associated with maintained feature binding. Source space (sLORETA) analyses indicated greater activity in networks modulated by frontoparietal and temporal regions. Our results demonstrate there may be increased involvement of neurocognitive control networks to maintain lower-order neurocognitive processing disrupted by ARHL.

Social processing modulates the initial allocation of attention towards angry faces: evidence from the N2pc component

Previous research has shown that attentional bias towards angry faces is moderated by the activation of a social processing mode. More specifically, reliable cueing effects for angry face cues in the dot-probe task only occurred when participants performed a task that required social processing of the target stimuli. However, cueing effects are a rather distal measure of covert shifts in spatial attention. Thus, it remains unclear whether the social processing mode modulates initial allocation of attention to or attentional disengagement from angry faces. In the present study, we used the N2pc, an event-related potential component, as an index of attentional shifts towards angry faces. Participants performed a dot-probe task with two different target conditions while the electroencephalogram (EEG) was recorded. In the social target condition, target stimuli were socially meaningful (schematic faces), and in the non-social target condition, they were meaningless (scrambled schematic faces). The amplitude of the N2pc component elicited by angry face cues was significantly larger in the social target condition than in the non-social target condition. This pattern also occurred for behavioural cueing effects. These results suggest that the activation of a social processing mode due to current task demands affects the initial allocation of attention towards angry faces.

Unraveling the influence of trial-based motivational changes on performance monitoring stages in a flanker task

Performance monitoring (PM) is a vital component of adaptive behavior and known to be influenced by motivation. We examined effects of potential gain (PG) and loss avoidance (LA) on neural correlates of PM at different processing stages, using a task with trial-based changes in these motivational contexts. Findings suggest more attention is allocated to the PG context, with higher amplitudes for respective correlates of stimulus and feedback processing. The PG context favored rapid responses, while the LA context emphasized accurate responses. Lower response thresholds in the PG context after correct responses derived from a drift-diffusion model also indicate a more approach-oriented response style in the PG context. This cognitive shift is mirrored in neural correlates: negative feedback in the PG context elicited a higher feedback-related negativity (FRN) and higher theta power, whereas positive feedback in the LA context elicited higher P3a and P3b amplitudes, as well as higher theta power. There was no effect of motivational context on response-locked brain activity. Given the similar frequency of negative feedback in both contexts, the elevated FRN and theta power in PG trials cannot be attributed to variations in reward prediction error. The observed variations in the FRN indicate that the effect of outcome valence is modulated by motivational salience.

The overgeneralization of pain-related fear in individuals with higher pain sensitivity: A behavioral and event-related potential study

Fear generalization contributes to the development and maintenance of pain. Pain sensitivity has been proposed to predict the strength of fear responses to aversive stimuli. However, whether individual variation in pain sensitivity affects pain-related fear generalization and its underlying cognitive processing remains unclear. To address this gap, we recorded behavioral and event-related potential (ERP) data among 22 high pain sensitivity (HPS) and 22 low pain sensitivity (LPS) healthy adults when exposed to a fear generalization paradigm. The behavioral results indicate that the HPS group displayed higher unconditioned stimulus expectancy and greater fear, arousal, and anxiety ratings to conditioned stimulus and generalization stimulus than the LPS group (all p values < 0.05). The ERP results showed that the HPS group exhibited a larger late positive potential evoked by GS2, GS3 and CS- (all p < 0.005) but a smaller N1 evoked by all CS and GSs (all p values < 0.05) relative to the LPS group. These findings suggest that individuals with a high level of pain sensitivity allocate more attention resources to pain-related threatening stimuli, which contributes to an overgeneralization of pain-related fear.

Recursive structures modulate the electrophysiological correlates of visual perspective taking

An increasing number of studies have focused on the neural basis of complex mental inferences, which requires an understanding of the recursive nature of thought; however, the precise electrophysiological response to a recursive structure remains unclear. The present event-related potential (ERP) study investigated the recursive structure effect on the neural correlates of visual perspective taking by modifying a third-person visual perspective-taking task. Participants were required to determine how many dots in the presented scenes could be seen from the cued perspective, including the perspectives in the self, other, and recursive (one avatar's belief of another avatar) conditions. The ERP results showed that the N100 and P200 components specific to the recursive-perspective condition showed greater attentional allocation; the N200 component increased in the recursive condition and was related to the conflict process; and larger late slow waves were found in the other- and recursive-perspective conditions compared with those in the self-perspective condition, which reflected the decoupling mechanism. The results suggested that high-order perspective taking requires more attentional resources and conflict processing for further decoupling from the self-perspective.

The Distractor Positivity Component and the Inhibition of Distracting Stimuli

There has been a long-lasting debate about whether salient stimuli, such as uniquely colored objects, have the ability to automatically distract us. To resolve this debate, it has been suggested that salient stimuli do attract attention but that they can be suppressed to prevent distraction. Some research supporting this viewpoint has focused on a newly discovered ERP component called the distractor positivity (PD), which is thought to measure an inhibitory attentional process. This collaborative review summarizes previous research relying on this component with a specific emphasis on how the PD has been used to understand the ability to ignore distracting stimuli. In particular, we outline how the PD component has been used to gain theoretical insights about how search strategy and learning can influence distraction. We also review alternative accounts of the cognitive processes indexed by the PD component. Ultimately, we conclude that the PD component is a useful tool for understanding inhibitory processes related to distraction and may prove to be useful in other areas of study related to cognitive control.

Decrease in the P2 Amplitude of Object Working Memory after 8 h-Recovery Sleep Following 36 h-Total Sleep Deprivation: An ERP Study

The impact of sleep deprivation on working memory can only be reversed by recovery sleep (RS). However, there are limited electrophysiological studies on the effect of RS on the improvement in working memory after sleep deprivation, and the changes in the early components of event-related potentials (ERPs) before and after RS are still unclear. Therefore, this study aims to explore the effects of RS on the earlier ERP components related to object working memory following 36 h of total sleep deprivation (TSD). Twenty healthy male participants performed an object working memory task after 36 h of TSD and after 8 h of RS. Electroencephalogram data were recorded accordingly while the task was performed. Repeated ANOVA showed that P2 amplitudes related to object working memory decreased significantly after 8 h of RS compared to after a 36 h period of TSD, but there was no significant difference from baseline (BS), which indicates a trend of recovery to the baseline state. An 8 h RS can partially improve impaired object working memory caused by TSD. However, a longer period of RS is needed for the complete recovery of cognitive function after a long period of TSD.

EEG cortical network reveals the temporo-spatial mechanism of visual search

This study aims to explore a method based on brain networks for implicit attention by using wavelet coherence as feature to identify individual targets in the visual field, find the optimal classification rhythm and time window, and investigate the relationship between the optimal rhythm and N2pc event-related potential. The study uses a weighted minimum norm estimate to locate the sources of the scalp EEG and reconstructs the source time series. The functional connectivity between brain areas during the visual search process is evaluated using wavelet coherence analysis, and a lateral difference network is constructed based on the difference in coherence values between the left and right visual fields. A support vector machine classifier is trained based on the wavelet coherence network features to identify the target in the left or right visual field. We also extract N2pc from the source activity data of the parieto-occipital brain region and record the time period in which N2pc occurred. The study finds that the best classification performance is achieved in the theta rhythm from 200 to 400 ms and achieved an average classification accuracy of 87% (chance level: 51.07%) in a serial search task. And this time window corresponds to the time period when N2pc appeared. The results show that the use of wavelet coherence analysis to evaluate the functional connectivity between brain areas during the visual search process provides a new approach for analyzing brain activity. The study's findings regarding the relationship between the N2pc and theta rhythm and the effectiveness of using wavelet coherence network features based on the theta rhythm for visual search classification contribute to the understanding of the neural mechanisms underlying visual search.

Dissociating different temporal stages of emotional word processing by feature-based attention

Negative emotional content is prioritized across different stages of information processing as reflected by different components of the event-related potential (ERP). In this preregistered study (N = 40), we investigated how varying the attentional focus allows us to dissociate the involvement of specific ERP components in the processing of negative and neutral words. Participants had to discriminate the orientation of lines overlaid onto the words, the word type (adjective/noun), or the emotional content (negative/neutral). Thus, attention was either not focused on words (distraction task), non-emotional aspects, or the emotional relevance of words. Regardless of the task, there were no significant differences between negative and neutral words for the P1, N1, or P2 components. In contrast, interactions between emotion and task were observed for the early posterior negativity (EPN) and late positive potential (LPP). EPN differences were absent during the distraction task but were present in the other two tasks. LPP emotion differences were found only when attention was directed to the emotional content of words. Our study adds to the evidence that early ERP components do not reliably separate negative and neutral words. However, results show that mid-latency and late stages of emotion processing are separable by different attention tasks. The EPN represents a stage of attentional enhancement of negative words given sufficient attentional resources. Differential activations during the LPP stage are associated with more elaborative processing of the emotional meaning of words.

Beyond facial expressions: A systematic review on effects of emotional relevance of faces on the N170

The N170 is the most prominent electrophysiological signature of face processing. While facial expressions reliably modulate the N170, there is considerable variance in N170 modulations by other sources of emotional relevance. Therefore, we systematically review and discuss this research area using different methods to manipulate the emotional relevance of inherently neutral faces. These methods were categorized into (1) existing pre-experimental affective person knowledge (e.g., negative attitudes towards outgroup faces), (2) experimentally instructed affective person knowledge (e.g., negative person information), (3) contingency-based affective learning (e.g., fear-conditioning), or (4) the immediate affective context (e.g., emotional information directly preceding the face presentation). For all categories except the immediate affective context category, the majority of studies reported significantly increased N170 amplitudes depending on the emotional relevance of faces. Furthermore, the potentiated N170 was observed across different attention conditions, supporting the role of the emotional relevance of faces on the early prioritized processing of configural facial information, regardless of low-level differences. However, we identified several open research questions and suggest venues for further research.

The influence of perceptual and semantic chunking on the neural mechanism of remote association

Studies on remote association tests (RATs) have mainly focused on cognitive processes involved in searching for remote associations. However, factors affecting these search processes and remote associations remain unclear. In order to address this issue, this study compared non-chunking condition (e.g., "//") with perceptual chunking (two red color characters in the three-character item "//") and semantic chunking (high-frequency word-pair in the item; e.g., "//", "," literally "philosophy") conditions in the Chinese Remote Association Test (CRAT). The behavioral results on the CRAT found that the semantic ones resulted in significantly lower successful solving rates and longer response times than the other two conditions. The event-related potential (ERP) results showed that in contrast to the perceptual-chunking and the non-chunking condition, the semantic-chunking elicited enhanced P200, which might be related to the intuitive awareness of the mental fixation. However, relative to the non-chunking condition, the two chunking conditions evoked increased N400 and late positive component (LPC), indexing the late reflection and implementation of cognitive control. Our results suggest that it is the early awareness of the semantic chunk, rather than the general cognitive control process involved in representing and solving the semantically and perceptually chunk-induced interferences, that critically determines the final solving of RATs.

Cross-modal enhancement of spatially unpredictable visual target discrimination during the attentional blink

The attentional blink can be substantially reduced by delivering a task-irrelevant sound synchronously with the second target (T2) embedded in a rapid serial visual presentation stream, which is further modulated by the semantic congruency between the sound and T2. The present study extended the cross-modal boost during attentional blink and the modulation of audiovisual semantic congruency in the spatial domain by showing that a spatially uninformative, semantically congruent (but not incongruent) sound could even improve the discrimination of spatially unpredictable T2 during attentional blink. T2-locked event-related potential (ERP) data yielded that the early cross-modal P195 difference component (184-234 ms) over the occipital scalp contralateral to the T2 location was larger preceding accurate than inaccurate discriminations of semantically congruent, but not incongruent, audiovisual T2s. Interestingly, the N2pc component (194-244 ms) associated with visual-spatial attentional allocation was enlarged for incongruent audiovisual T2s relative to congruent audiovisual and unisensory visual T2s only when they were accurately discriminated. These ERP findings suggest that the spatially extended cross-modal boost during attentional blink involves an early cross-modal interaction strengthening the perceptual processing of T2, without any sound-induced enhancement of visual-spatial attentional allocation toward T2. In contrast, the absence of an accuracy decrease in response to semantically incongruent audiovisual T2s may originate from the semantic mismatch capturing extra visual-spatial attentional resources toward T2.

Electrophysiological evidence of crossmodal correspondence between auditory pitch and visual elevation affecting inhibition of return

Inhibition of return (IOR) has proved to be weakened by audiovisual integration because of the increased perceptual salience of targets. Although other audiovisual interactions, such as crossmodal correspondence, have also been shown to facilitate attentional processes, to the best of our knowledge, no study has investigated the interaction between crossmodal correspondence and IOR. The present study employed Posner's spatial cueing paradigm and manipulated the cue validity, crossmodal correspondence congruency and time interval of auditory and visual stimuli (AV interval) to explore the effect of crossmodal correspondence on the IOR effect. The behavioral results showed a reduced IOR effect under the correspondence congruency condition in contrast to the correspondence incongruency condition at the AV interval of 200 ms, whereas at an AV interval of 80 ms, the decreased IOR effect under crossmodal correspondence congruency was eliminated. The electrophysiological results showed a reduced amplitude difference in P2 between valid and invalid cue conditions when the crossmodal correspondence effect decreased the IOR effect. The present study provided the first evidence of the weakened effect of the crossmodal correspondence effect on the IOR effect, which could be eliminated by audiovisual integration.

Effects of noise and noise reduction on audiovisual speech perception in cochlear implant users: An ERP study

OBJECTIVE

Hearing with a cochlear implant (CI) is difficult in noisy environments, but the use of noise reduction algorithms, specifically ForwardFocus, can improve speech intelligibility. The current event-related potentials (ERP) study examined the electrophysiological correlates of this perceptual improvement.

METHODS

Ten bimodal CI users performed a syllable-identification task in auditory and audiovisual conditions, with syllables presented from the front and stationary noise presented from the sides. Brainstorm was used for spatio-temporal evaluation of ERPs.

RESULTS

CI users revealed an audiovisual benefit as reflected by shorter response times and greater activation in temporal and occipital regions at P2 latency. However, in auditory and audiovisual conditions, background noise hampered speech processing, leading to longer response times and delayed auditory-cortex-activation at N1 latency. Nevertheless, activating ForwardFocus resulted in shorter response times, reduced listening effort and enhanced superior-frontal-cortex-activation at P2 latency, particularly in audiovisual conditions.

CONCLUSIONS

ForwardFocus enhances speech intelligibility in audiovisual speech conditions by potentially allowing the reallocation of attentional resources to relevant auditory speech cues.

SIGNIFICANCE

This study shows for CI users that background noise and ForwardFocus differentially affect spatio-temporal cortical response patterns, both in auditory and audiovisual speech conditions.

Suppressive Control of Incentive Salience in Real-World Human Vision

Reward-related activity in the dopaminergic midbrain is thought to guide animal behavior, in part by boosting the perceptual and attentional processing of reward-predictive environmental stimuli. In line with this incentive salience hypothesis, studies of human visual search have shown that simple synthetic stimuli, such as lines, shapes, or Gabor patches, capture attention to their location when they are characterized by reward-associated visual features, such as color. In the real world, however, we commonly search for members of a category of visually heterogeneous objects, such as people, cars, or trees, where category examples do not share low-level features. Is attention captured to examples of a reward-associated real-world object category? Here, we have human participants search for targets in photographs of city and landscapes that contain task-irrelevant examples of a reward-associated category. We use the temporal precision of EEG machine learning and ERPs to show that these distractors acquire incentive salience and draw attention, but do not capture it. Instead, we find evidence of rapid, stimulus-triggered attentional suppression, such that the neural encoding of these objects is degraded relative to neutral objects. Humans appear able to suppress the incentive salience of reward-associated objects when they know these objects will be irrelevant, supporting the rapid deployment of attention to other objects that might be more useful. Incentive salience is thought to underlie key behaviors in eating disorders and addiction, among other conditions, and the kind of suppression identified here likely plays a role in mediating the attentional biases that emerge in these circumstances.Significance Statement Like other animals, humans are prone to notice and interact with environmental objects that have proven rewarding in earlier experience. However, it is common that such objects have no immediate strategic use and are therefore distracting. Do these reward-associated real-world objects capture our attention, despite our strategic efforts otherwise? Or are we able to strategically control the impulse to notice them? Here we use machine learning classification of human electrical brain activity to show that we can establish strategic control over the salience of naturalistic reward-associated objects. These objects draw our attention, but do not necessarily capture it, and this kind of control may play an important role in mediating conditions like eating disorder and addiction.

Is covert attention necessary for programming accurate saccades? Evidence from saccade-locked event-related potentials

For decades, researchers have assumed that shifts of covert attention mandatorily occur prior to eye movements to improve perceptual processing of objects before they are fixated. However, recent research suggests that the N2pc component-a neural measure of covert attentional allocation-does not always precede eye movements. The current study investigated whether the N2pc component mandatorily precedes eye movements and assessed its role in the accuracy of gaze control. In three experiments, participants searched for a letter of a specific color (e.g., red) and directed gaze to it as a response. Electroencephalograms and eye movements were coregistered to determine whether neural markers of covert attention preceded the initial shift of gaze. The results showed that the presaccadic N2pc only occurred under limited conditions: when there were many potential target locations and distractors. Crucially, there was no evidence that the presence or magnitude of the presaccadic N2pc was associated with improved eye movement accuracy in any of the experiments. Interestingly, ERP decoding analyses were able to classify the target location well before the eyes started to move, which likely reflects a presaccadic cognitive process that is distinct from the attentional process measured by the N2pc. Ultimately, we conclude that the covert attentional mechanism indexed by the N2pc is not necessary for precise gaze control.

Distinct roles of theta and alpha oscillations in the process of contingent attentional capture

Introduction

Visual spatial attention can be captured by a salient color singleton that is contingent on the target feature. A previous study reported that theta (4-7 Hz) and alpha (8-14 Hz) oscillations were related to contingent attentional capture, but the corresponding attentional mechanisms of these oscillations remain unclear.

Methods

In this study, we analyzed the electroencephalogram data of our previous study to investigate the roles of capture-related theta and alpha oscillation activities. Different from the previous study that used color-changed placeholders as irrelevant cues, the present study adopted abrupt onsets of color singleton cues which tend to elicit phase-locked neural activities. In Experiment 1, participants completed a peripheral visual search task in which spatially uninformative color singleton cues were inside the spatial attentional window and a central rapid serial visual presentation (RSVP) task in which the same cues were outside the spatial attentional window. In Experiment 2, participants completed a color RSVP task and a size RSVP task in which the peripheral color singleton cues were contingent and not contingent on target feature, respectively.

Results

In Experiment 1, spatially uninformative color singleton cues elicited lateralized theta activities when they were contingent on target feature, irrespective of whether they were inside or outside the spatial attentional window. In contrast, the same color singleton cues elicited alpha lateralization only when they were inside the spatial attentional window. In Experiment 2, we further found that theta lateralization vanished if the color singleton cues were not contingent on target feature.

Discussion

These results suggest distinct roles of theta and alpha oscillations in the process of contingent attentional capture initiated by abrupt onsets of singleton cues. Theta activities may reflect global enhancement of target feature, while alpha activities may be related to attentional engagement to spatially relevant singleton cues. These lateralized neural oscillations, together with the distractor-elicited N2pc component, might consist of multiple stages of attentional processes during contingent attentional capture.

A comparison of mental imagery and perceptual cueing across domains of attention

Mental imagery and perceptual cues can influence subsequent visual search performance, but examination of this influence has been limited to low-level features like colors and shapes. The present study investigated how the two types of cues influence low-level visual search, visual search with realistic objects, and executive attention. On each trial, participants were either presented with a colored square or tasked with using mental imagery to generate a colored square that could match the target (valid trial) or distractor (invalid trial) in the search array that followed (Experiments 1 and 3). In a separate experiment, the colored square displayed or generated was replaced with a realistic object in a specific category that could appear as a target or distractor in the search array (Experiment 2). Although the displayed object was in the same category as an item in the search display, they were never a perfect match (e.g., jam drop cookie instead of chocolate chip). Our findings revealed that the facilitation of performance on valid trials compared with invalid trials was greater for perceptual cues than imagery cues for low-level features (Experiment 1), whereas the influence of these two types of cues was comparable in the context of realistic objects (Experiment 2) The influence of mental imagery appears not to extend to the resolution of conflict generated by color-word Stroop stimuli (Experiment 3). The present findings extend our understanding of how mental imagery influences the allocation of attention.