Frontal two-electrode transcranial direct current stimulation protocols may not affect performance on a combined flanker Go/No-Go task

Transcranial direct current stimulation (tDCS) has been tested to modulate cognitive control or response inhibition using various electrode montages. However, electrode montages and current polarities have not been systematically compared when examining tDCS effects on cognitive control and response inhibition. In this randomized, sham-controlled study, 38 healthy volunteers were randomly grouped into receiving one session of sham, anodal, and cathodal each in an electrode montage that targeted either the dorsolateral prefrontal cortex (DLPFC) or the fronto-medial (FM) region. Participants performed a combined flanker Go/No-Go task during stimulation. No effect of tDCS was found in the DLPFC and FM groups neither using anodal nor cathodal stimulation. No major adverse effects of tDCS were identified using either montage or stimulation type and the two groups did not differ in terms of the reported sensations. The present study suggests that single-session tDCS delivered in two two-electrode montages might not affect cognitive control or response inhibition, despite using widely popular stimulation parameters. This is in line with the heterogeneous findings in the field and calls for further systematic research to exclude less reliable methods from those with more pronounced effects, identify the determinants of responsiveness, and develop optimal ways to utilize this technique

Environmental concern as a moderator of information processing: A fMRI study

The psychological processes that predict behaviour can be influenced by the approaches taken in environmental awareness messages. The persuasiveness generated by different approaches depends on the environmental concern of viewers. The study identifies brain regions active while processing positive advertisements. It also studies brain activity in subjects with high (vs low) environmental concern while processing positive ads. In addition, it relates the brain activity evoked in response to positive ads which predicts more significant attitudes toward the ads, in subjects with great environmental concern. The results indicate that positive messages activate regions linked to self-value and societal benefit in those subjects who are more concerned. We found a stronger effect in regions linked to an emotional response in viewers with greater environmental concern. The identified emotional response may precede higher attitudinal ratings

The role of the left head of caudate in suppressing irrelevant words

Suppressing irrelevant words is essential to successful speech production and is expected to involve general control mechanisms that reduce interference from task-unrelated processing. To investigate the neural mechanisms that suppress visual word interference, we used fMRI and a Stroop task, using a block design with an event-related analysis. Participants indicated with a finger press whether a visual stimulus was colored pink or blue. The stimulus was either the written word "BLUE," the written word "PINK," or a string of four Xs, with word interference introduced when the meaning of the word and its color were "incongruent" (e.g., BLUE in pink hue) relative to congruent (e.g., BLUE in blue) or neutral (e.g., XXXX in pink). The participants also made color decisions in the presence of spatial interference rather than word interference (i.e., the Simon task). By blocking incongruent, congruent, and neutral trials, we identified activation related to the mechanisms that suppress interference as that which was greater at the end relative to the start of incongruency. This highlighted the role of the left head of caudate in the control of word interference but not spatial interference. The response in the left head of caudate contrasted to bilateral inferior frontal activation that was greater at the start than at the end of incongruency, and to the dorsal anterior cingulate gyrus which responded to a change in the motor response. Our study therefore provides novel insights into the role of the left head of caudate in the mechanisms that suppress word interference

Neural Correlates Related to Anxiety in Attentional Inhibition Control: an Erp Study

We investigated the effect of anxiety on attentional inhibitory control using event-related potentials (ERPs) and measuring the response time. Nineteen participants performed a multisource interference task; three-digit numbers and emotional faces were used as visual stimuli. The P100 and P300 ERP-components and response time values were used to evaluate whether ERP parameters and behavioral responses are associated with increased anxiety. Higher anxiety was associated with a longer latency and reduced amplitude of the P300 component at F3, whereas higher anxiety was associated with a shorter latency and higher amplitude of P300 at F4. The longer P300 latency at F3 was especially related to the response time to the target number with negative-expression faces as distracters.Ми досліджували вплив рівня тривожності на гальмівний контроль уваги з використанням реєстрації пов’язаних із подією потенціалів (ППП) та вимірювання часу реакції. 19 тестованих виконували мультистимульний тест з інтерференцією; як візуальні стимули застосовували зображення тризначних чисел та облич з емоціональними виразами. Параметри Р100 та Р300 компонентів ППП та час реакції брали до уваги для того, щоб визначити можливість асоційованості параметрів ППП та поведінкових відповідей з рівнем тривожності. Підвищена тривожність була асоційована з довшими латентними періодами та зниженою амплітудою компонента Р300 у відведенні F3, тоді як такий рівень тривожності асоціювався з меншими величинами латентного періоду цієї ж самої хвилі та її вищою амплітудою у відведенні F4. Більший латентний період Р300 у відведенні F3 особливо чітко корелював із часом відповіді на цільове число на тлі облич із негативними виразами як відволікаючих факторів

Emotional salience but not valence impacts anterior cingulate cortex conflict processing

Stimuli that evoke emotions are salient, draw attentional resources, and facilitate situationally appropriate behavior in complex or conflicting environments. However, negative and positive emotions may motivate different response strategies. For example, a threatening stimulus might evoke avoidant behavior, whereas a positive stimulus may prompt approaching behavior. Therefore, emotional stimuli might either elicit differential behavioral responses when a conflict arises or simply mark salience. The present study used functional magnetic resonance imaging to investigate valence-specific emotion effects on attentional control in conflict processing by employing an adapted flanker task with neutral, negative, and positive stimuli. Slower responses were observed for incongruent than congruent trials. Neural activity in the dorsal anterior cingulate cortex was associated with conflict processing regardless of emotional stimulus quality. These findings confirm that both negative and positive emotional stimuli mark salience in both low (congruent) and high (incongruent) conflict scenarios. Regardless of the conflict level, emotional stimuli deployed greater attentional resources in goal directed behavior

Context specificity of post-error and post-conflict cognitive control adjustments

There has been accumulating evidence that cognitive control can be adaptively regulated by monitoring for processing conflict as an index of online control demands. However, it is not yet known whether top-down control mechanisms respond to processing conflict in a manner specific to the operative task context or confer a more generalized benefit. While previous studies have examined the taskset-specificity of conflict adaptation effects, yielding inconsistent results, controlrelated performance adjustments following errors have been largely overlooked. This gap in the literature underscores recent debate as to whether post-error performance represents a strategic, control-mediated mechanism or a nonstrategic consequence of attentional orienting. In the present study, evidence of generalized control following both high conflict correct trials and errors was explored in a task-switching paradigm. Conflict adaptation effects were not found to generalize across tasksets, despite a shared response set. In contrast, post-error slowing effects were found to extend to the inactive taskset and were predictive of enhanced post-error accuracy. In addition, post-error performance adjustments were found to persist for several trials and across multiple task switches, a finding inconsistent with attentional orienting accounts of post-error slowing. These findings indicate that error-related control adjustments confer a generalized performance benefit and suggest dissociable mechanisms of post-conflict and post-error control. © 2014 Forster, Cho

Is there electrophysiological evidence for a bilingual advantage in neural processes related to executive functions?

Available online 3 August 2020Over the last two decades, a large number of studies have concluded that bilingualism enhances executive functions. However, other studies have reported no significant results. In addition, it is not clear how bilingualism might modulate specific executive control processes. Event-related potentials (ERP) are an excellent technique for identifying whether the neural correlates of executive control processes are strengthened by bilingualism, given their high temporal resolution. On the basis of previous research into the ERP correlates of executive functions, we hypothesize that specific ERP differences between monolinguals and bilinguals can be considered to indicate a bilingual advantage in executive functions. We then review the very limited number of studies that have investigated ERP differences between monolinguals and bilinguals during the performance of executive control tasks. Overall, we conclude that the existence of a bilingual advantage in neural processing related to executive functions remains uncertain and further studies are required. We highlight the utility of investigating several ERPs that have been ignored by previous studies.This study was funded by the Spanish government (Juan de la Cierva-Incorporación Postdoctoral Grant), European Commission (Marie Skłodowska-Curie actions 838536_BILINGUALPLAS), Basque Government (BERC 2018-2021 program), BCBL Severo Ochoa excellence accreditation SEV-2015-0490, and Grant RTI2018-093547-BI00 from the Agencia Estatal de Investigación

The Unique Effects of Relatively Recent Conflict on Cognitive Control

In tasks such as Stroop, our past experiences with conflict influence our ability to attend to goal-relevant information and ignore irrelevant information. There exists evidence that conflict experiences on at least two timescales affect cognitive control. The “immediate” timescale is evidenced by congruency sequence effects while the “long” timescale is evidenced by list-wide proportion congruence effects. What remains underspecified is whether relatively recent experiences with conflict may also uniquely influence cognitive control and how experiences on different timescales are weighted. The present, pre-registered experiments aimed to assess the role of relatively recent conflict by examining the potential effects of an “intermediate” timescale (i.e., several preceding trials). A novel Stroop paradigm was developed to isolate the effects of the intermediate timescale and cognitive control was measured via frequency- and contingency-unbiased diagnostic items. In Experiment 1 (N = 61), I manipulated the level of conflict experienced in the intermediate timescale for lists matched in proportion congruence. Controlling for conflict experiences in the long and immediate timescales, I found that conflict in the intermediate timescale affected cognitive control. Experiment 2 (N = 60) found that the effect of conflict in the intermediate timescale may depend on that conflict defying the long timescale. These novel findings highlight the need to expand theories of cognitive control to incorporate the intermediate timescale and the interaction of the intermediate timescale with other timescales of cognitive control