Neural mechanisms underlying anxiety-related deficits of attentional inhibition: direct ERP evidence from the Pd component

Behavioral evidence shows that anxious individuals tend to be distracted by irrelevant stimulation not only for threat-related stimuli but also for non-emotional neutral stimuli. These findings suggest that anxious individuals may have a general impairment of attentional control, especially inhibition function. However, the neural mechanism underlying the anxiety-related impairment in attentional control is unclear. Here, in a visual search task with geometric stimuli, we examined attentional processing of the non-emotional neutral distractor on participants with different levels of anxiety, using the event-related-potential (ERP) indices of attentional selection (N2 posterior contralateral [N2pc]) and top-down inhibition (distractor positivity [Pd]). We found that distractor-evoked Pd amplitudes were negatively correlated with trait-anxiety scores, i.e., the higher the level of anxiety, the worse the ability of attentional inhibition. In contrast, the amplitudes of distractor-evoked N2pc did not vary with anxiety levels, suggesting that trait-anxiety level does not affect stimulus-driven attentional capture. We also observed attentional processing of target stimuli and found that the peak latency of target-evoked N2pc was delayed as anxiety levels rise, suggesting that anxiety impairs the efficiency of top-down attentional selection of the target. The present study provides direct neurophysiological evidence for general anxiety-related impairment of attentional control.

Tracking neural markers of template formation and implementation in attentional inhibition under different distractor consistency

To perform challenging visual search tasks, attention should be selectively allocated to promote targets and inhibit distractors. Rejection templates based on the distractor's feature can be built to constrain the search process by filtering-out matched stimuli. We measured electroencephalography (EEG) of human participants when they performed a visual search task under conditions in which the distractor cues were constant within a block (fixed-cueing) or changed on a trial-by-trial basis (varied-cueing). Sustained representation of the cued colors could be decoded from the whole-brain EEG signal during the retention interval in the fixed-cueing condition, implying a formed rejection template. By contrast, transient representation of the cued colors was observed in the varied-cueing condition only after cue onset with significant but lower decoding accuracy than the fixed-cueing condition. The differential neural representations of the to-be-ignored color in the two cueing conditions agreed with the visual search performance that the fixed-cueing condition demonstrated a larger inhibition benefit of the distractor cueing than the varied-cueing condition. During the retention interval, we also observed stronger posterior alpha lateralization and mid-frontal theta/beta power in the varied-cueing condition, indicating the cognitive costs in template formation caused by the trialwisely change of distractor colors. The stable template formed in the fixed-cueing condition was utilized to inhibit the matched distractors in the search array and this was accompanied by larger mid-frontal theta activity. Taken together, our findings highlighted the critical roles of distractor consistency in linking template formation to successful distractor inhibition and the functional relevance of frontal theta activity in support of template formation and implementation.

Response inhibition deficits are positively associated with trait rumination, but attentional inhibition deficits are not: aggressive behaviors and interpersonal stressors as mediators

Previous findings on relationships between inhibition that is a core executive function, and trait rumination have been inconsistent. This inconsistency could be overcome by investigating the association between rumination and the two subcomponents of inhibition: response inhibition and attentional inhibition. This study examined whether and how response inhibition and attentional inhibition were related to rumination as well as worry. University students in Japan (N = 213) conducted the Go/No-Go Task and the Modified Stroop Task. They also completed self-report measures of depression, trait rumination, trait worry, stressors, and aggressive behaviors. Results indicated that response inhibition deficits were positively associated with trait rumination, and this association was mediated by increases in aggressive behaviors and interpersonal stressors. The associations between these variables remained significant even after controlling for depression level. There were no significant direct or indirect associations between attentional inhibition deficits and rumination. These results suggest that response inhibition deficits, among the subcomponents of inhibition, have an indirect positive association with rumination through interpersonal processes. Results also showed nonsignificant differences between rumination and worry in the magnitude of correlation coefficients with the two subcomponents of inhibition. Therefore, it remains unclear whether the positive association with response inhibition is unique to rumination.

Decline in attentional inhibition among migraine patients: an event‐related potential study using the Stroop task

Background As a disorder of brain dysfunction, migraine has been associated with cognitive decline. However, no consistent results with respect to the attention function in migraineurs have been found, and the relationship between attentional inhibition and migraine is also unclear. In this study, the attentional inhibition function was evaluated using event-related potentials (ERPs) while migraine patients and healthy controls were performing the color–word Stroop task. Methods In this study, 75 migraine patients and 41 age-, gender-, and education-matched healthy controls were enrolled. The Stroop task was performed, and both behavioral and ERP data were analyzed. Results As to the behavioral data, the migraine group had a longer reaction time compared to the control group, but no difference in Stroop effect was observed. With respect to ERP components, the amplitudes of both early and late medial frontal negativity (MFN) were decreased in the migraine group. Additionally, obvious differences in the early MFN and sustained potential (SP) amplitudes were found between patients with and without allodynia. Conclusions At the behavioral level, migraine patients exhibited decreased executive ability but no obvious decline in inhibition. By contrast, a decline in attentional inhibition during the migraine interictal phase was confirmed by the analysis of ERP components, mainly those associated with changes in the conflict-monitoring stage, independent of confounding factors such as age, education, medication and mood disorders. Migraine patients with allodynia exhibited some significant differences in early MFN and SP compared to those without, supporting the hypothesis that migraine chronification aggravates the decline in attentional inhibition.

Acute alcohol does not impair attentional inhibition as measured with Stroop interference scores but impairs Stroop performance

Rationale Inhibition is a core executive function and refers to the ability to deliberately suppress attention, behavior, thoughts, and/or emotions and instead act in a specific manner. While acute alcohol exposure has been shown to impair response inhibition in the stop-signal and Go/NoGo tasks, reported alcohol effects on attentional inhibition in the Stroop task are inconsistent. Notably, studies have operationalized attentional inhibition variably and there has been intra- and inter-individual variability in alcohol exposure. Objective This study aimed to examine the acute effects of alcohol on attentional inhibition, considering previous limitations. Methods In a single-blind, cross-over design, 40 non-dependent participants with a medium-to-high risk drinking behavior performed a Counting Stroop task (CST) under a baseline and an arterial blood alcohol concentration (aBAC) clamp at 80 mg%. Attentional inhibition was assessed as the alteration of reaction times (RT), error rates (ER), and inverse efficiency scores (IES) between incongruent and congruent trials (interference score). Stroop performance was also assessed regardless of trial-type. Results Compared to saline, acute alcohol exposure via an aBAC clamp did not affect CST interference scores but increased RTs and IES in both incongruent and congruent trials. Conclusions Attentional inhibition (Stroop interference score) was not impaired by clamped moderate alcohol exposure. Acute alcohol impaired Stroop performance evidenced by a general increase in response times. Our findings suggest that response and attentional inhibition do not share the same neurocognitive mechanisms and are affected differently by alcohol. Results could also be explained by automated behaviors known to be relatively unaffected by acute alcohol.

Gaze dynamics of feature-based distractor inhibition under the prior-knowledge and expectation

Prior information about distractor facilitates selective attention to task-relevant items and helps the optimization of oculomotor planning. Particularly, feature-based attentional inhibition could be benefited from the pre-knowledge of critical features of the distractors. In the present study, we capitalized on gaze-position decoding to examine the dynamics of attentional deployment in a feature-based attentional task that involved two groups of dots (target/distractor dots) moving toward different directions. Specifically, this measurement revealed how pre-knowledge of the target’s or distractor’s direction modulated real-time feature-based attentional bias. In Experiment 1, participants were provided with target cues indicating the moving direction of target dots. The results showed that participants were biased towards the cued direction and tracked the target dots throughout the task period. In Experiment 2 and Experiment 3, participants were provided with cues that informed the moving direction of distractor dots. The results showed that participants would continuously monitor the distractor’s direction when the distractor cue varied on a trial-by-trial basis (Experiment 2). However, when the to-be-ignored distractor direction remained constant (Experiment 3), participants would strategically bias their attention to the distractor’s direction before the cue onset and reduce the cost of re-deployment of attention between trials. These results suggest that monitoring the distractor’s feature is a prerequisite for feature-based attentional inhibition and this process is facilitated by the predictability of the distractor’s feature.

Macular Carotenoids Are Associated with Neural Efficiency in Children

Objectives Macular pigmentation has been previously related to benefits for behavioral and neuroelectric aspects of selective attention across the lifespan. The relationship between accumulation of carotenoids beyond the central nervous system and selective attention is less understood, particularly amongst children. Therefore, this study aimed to assess the differential impacts of retinal and skin carotenoid accumulation and behavioral and neuroelectric indices of selective attention. Methods Children between 7–12 years (N = 60) participated in the study. Macular pigment optical density (MPOD) was assessed using heterochromatic flicker photometry and skin carotenoids were assessed using reflection spectroscopy at the fingertip using the Veggie meter. Body Mass Index adjusted for age and sex (BMI%) and general intelligence as assessed using the Woodcock Johnson IV test were used as covariates. Behavioral performance (accuracy and reaction time) and neuroelectric indices (event-related brain potentials [ERPs]) of attentional inhibition were assessed during a modified Eriksen Flanker task. Specifically, amplitude of the P3 waveform was used to index attentional resource allocation. Results After controlling for covariates, MPOD was selectively associated with lower peak amplitude of the P3 waveform during congruent (β = −0.36, P = 0.01) and incongruent task trials (β = −0.39, P < 0.01). No significant relationships were observed between the P3 and skin carotenoids. Skin carotenoids were associated with higher accuracy on the incongruent trials of the Flanker task (β = 0.36, P = 0.02), while no relationships were observed between MPOD and behavioral performance. Conclusions In this study, we were able to replicate previous findings demonstrating that higher accumulation of retinal carotenoids is associated with neural efficiency during a selective attention task. Skin carotenoids were associated with behavioral performance but were not related to neuroelectric indices of selective attention, suggesting site-specific benefits of carotenoid accumulation on cognitive health in childhood. Funding Sources This work is funded by the Egg Nutrition Center.