Conflict monitoring and adaptation to affective stimuli as a function of ageing.

The current study investigated whether preference for positive affect would be observed in the context of a higher order control process with increasing age given the premise of affective prioritization with ageing. The study examined how affect interacted with cognitive control mechanisms across young, middle-aged and older adults. Conflict monitoring and adaptation for affective stimuli was examined with a face-word Stroop task using happy and fearful facial expressions. The participants' task was to detect the emotional expression (Happy or Fear) of the face shown with a distractor word (Happy or Fear) written across the face. Reaction time and accuracy data was analysed to compare adaptation effect and Stroop interference as a function of age, valence and previous trial congruence. The results demonstrated a stronger adaptation effect for negative affect in young adults and for positive affect in middle-aged adults and older adults. These results can be explained in terms of the socio-emotional selectivity theory of affective bias in the elderly and the involvement of attentional control mechanisms. This study empirically demonstrates shifts in affective bias towards positive affect with ageing through the implicit recruitment of cognitive control.

Stroop interference is a composite phenomenon: Evidence from distinct developmental trajectories of its components.

Only one previous developmental study of Stroop task performance (Schiller, 1966) has controlled for differences in processing speed that exist both within and between age groups. Therefore, the question of whether the early developmental change in the magnitude of Stroop interference actually persists after controlling for processing speed needs further investigation; work that is further motivated by the possibility that any remaining differences would be caused by process(es) other than processing speed. Analysis of data from two experiments revealed that, even after controlling for processing speed using z-transformed reaction times, early developmental change persists such that the magnitude of overall Stroop interference is larger in 3rd- and 5th graders as compared to 1st graders. This pattern indicates that the magnitude of overall Stroop interference peaks after 2 or 3 years of reading practice (Schadler & Thissen, 1981). Furthermore, this peak is shown to be due to distinct components of Stroop interference (resulting from specific conflicts) progressively falling into place. Experiment 2 revealed that the change in the magnitude of Stroop interference specifically results from joint contributions of task, semantic and response conflicts in 3rd- and 5th graders as compared to a sole contribution of task conflict in 1st graders. The specific developmental trajectories of different conflicts presented in the present work provide unique evidence for multiple loci of Stroop interference in the processing stream (respectively task, semantic and response conflict) as opposed to a single (i.e. response) locus predicted by historically - favored response competition accounts.

A transferable high-intensity intermittent exercise improves executive performance in association with dorsolateral prefrontal activation in young adults.

Although growing attention has been drawn to attainable, high-intensity intermittent exercise (HIE)-based intervention, which can improve cardiovascular and metabolic health, for sedentary individuals, there is limited information on the impact and potential benefit of an easily attainable HIE intervention for cognitive health. We aimed to reveal how acute HIE affects executive function focusing on underlying neural substrates. To address this issue, we examined the effects of acute HIE on executive function using the color-word matching Stroop task (CWST), which produces a cognitive conflict in the decision-making process, and its neural substrate using functional near infrared spectroscopy (fNIRS). Twenty-five sedentary young adults (mean age: 21.0 ± 1.6 years; 9 females) participated in two counter-balanced sessions: HIE and resting control. The HIE session consisted of two minutes of warm-up exercise (50 W load at 60 rpm) and eight sets of 30 s of cycling exercise at 60% of maximal aerobic power (mean: 127 W ± 29.5 load at 100 rpm) followed by 30 s of rest on a recumbent-ergometer. Participants performed a CWST before and after the 10-minute exercise session, during both of which cortical hemodynamic changes in the prefrontal cortex were monitored using fNIRS. Acute HIE led to improved Stroop performance reflected by a shortening of the response time related to Stroop interference. It also evoked cortical activation related to Stroop interference on the left-dorsal-lateral prefrontal cortex (DLPFC), which corresponded significantly with improved executive performance. These results provide the first empirical evidence using a neuroimaging method, to our knowledge, that acute HIE improves executive function, probably mediated by increased activation of the task-related area of the prefrontal cortex including the left-DLPFC.

Prefrontal Volume Mediates Effect of COMT Polymorphism on Interference Resolution Capacity in Healthy Male Adults.

There exist gender differences in the modulation of catechol-O-methyltransferase (COMT) Val158Met polymorphism on cognitive performance; however, the underlying gene-anatomy-cognition pathways remain unknown. Here we hypothesize that prefrontal volume may mediate the modulation of COMT Val158Met polymorphism on interference resolution capacity in a gender-dependent manner. In 261 healthy young human subjects (143 males and 118 females), a 2-way analysis of variance showed a COMT × gender interaction (P = 0.023) on interference resolution capacity. Val/Val subjects performed worse in Stroop interference test than Met/Met subjects only in males (P = 0.028). Voxel-wise analysis in the whole brain also exhibited a COMT × gender interaction on gray matter volume (GMV) in the left lateral frontal pole (FP). Val/Val male individuals exhibited significantly decreased GMV in the left lateral FP than Val/Met (P = 0.003) and Met/Met (P = 0.006) male carriers. Mediation analysis revealed that the GMV of the left lateral FP mediated the association between COMT polymorphism and interference resolution in males. These findings provide a gene-anatomy-cognition pathway to describe how COMT Val158Met polymorphism affects interference resolution capacity via modulating the prefrontal GMV in healthy male subjects.

Metabolic alterations in the anterior cingulate cortex and related cognitive deficits in late adolescent methamphetamine users.

The adolescent brain, with ongoing prefrontal maturation, may be more vulnerable to drug use-related neurotoxic changes as compared to the adult brain. We investigated whether the use of methamphetamine (MA), a highly addictive psychostimulant, during adolescence affect metabolic and cognitive functions of the anterior cingulate cortex (ACC). In adolescent MA users (n = 44) and healthy adolescents (n = 53), the levels of N-acetyl aspartate (NAA), a neuronal marker, were examined in the ACC using proton magnetic resonance spectroscopy. The Stroop color-word task was used to assess Stroop interference, which may reflect cognitive functions of behavior monitoring and response selection that are mediated by the ACC. Adolescent MA users had lower NAA levels in the ACC (t = -2.88, P = 0.005) and relatively higher interference scores (t = 2.03, P = 0.045) than healthy adolescents. Moreover, there were significant relationships between lower NAA levels in the ACC and worse interference scores in adolescent MA users (r = -0.61, P < 0.001). Interestingly, early onset of MA use, as compared to late onset, was related to both lower NAA levels in the ACC (t = -2.24, P = 0.03) as well as lower performance on interference measure of the Stroop color-word task (t = 2.25, P = 0.03). The current findings suggest that metabolic dysfunction in the ACC and its related cognitive impairment may play an important role in adolescent-onset addiction, particularly during early adolescence.

Reevaluating the two-representation model of numerical magnitude processing.

One debate in mathematical cognition centers on the single-representation model versus the two-representation model. Using an improved number Stroop paradigm (i.e., systematically manipulating physical size distance), in the present study we tested the predictions of the two models for number magnitude processing. The results supported the single-representation model and, more importantly, explained how a design problem (failure to manipulate physical size distance) and an analytical problem (failure to consider the interaction between congruity and task-irrelevant numerical distance) might have contributed to the evidence used to support the two-representation model. This study, therefore, can help settle the debate between the single-representation and two-representation models.

Dissociating proactive and reactive control in the Stroop task.

The Dual Mechanisms of Control framework posits the existence of two distinct control mechanisms, proactive and reactive, which may operate independently. However, this independence has been difficult to study with most experimental paradigms. The Stroop task may provide a useful way of assessing the independence of control mechanisms because the task elicits two types of proportion congruency effects, list-wide and item-specific, thought to reflect proactive and reactive control respectively. The present research tested whether these two proportion congruency effects can be used to dissociate proactive and reactive control. In 2 separate participant samples, we demonstrate that list-wide and item-specific proportion congruency effects are stable, exist in the same participants, and appear in different task conditions. Moreover, we identify two distinct behavioral signatures, the congruency cost and the transfer cost, which doubly dissociate the two effects. Together, the results are consistent with the view that proactive and reactive control reflect independent mechanisms.

Degree centrality and fractional amplitude of low-frequency oscillations associated with Stroop interference.

Stroop paradigms are commonly used as an index of attention deficits and a tool for investigating functions of the frontal lobes and other associated structures. Here we investigated the correlation between resting-state functional magnetic imaging (fMRI) measures [degree centrality (DC)/fractional amplitude of low frequency fluctuations (fALFFs)] and Stroop interference. We examined this relationship in the brains of 958 healthy young adults. DC reflects the number of instantaneous functional connections between a region and the rest of the brain within the entire connectivity matrix of the brain (connectome), and thus how much of the node influences the entire brain areas, while fALFF is an indicator of the intensity of regional brain spontaneous activity. Reduced Stroop interference was associated with larger DC in the left lateral prefrontal cortex, left IFJ, and left inferior parietal lobule as well as larger fALFF in the areas of the dorsal attention network and the precuneus. These findings suggest that Stroop performance is reflected in resting state functional properties of these areas and the network. In addition, default brain activity of the dorsal attention network and precuneus as well as higher cognitive processes represented there, and default stronger global influence of the areas critical in executive functioning underlie better Stroop performance.

Sleep deprivation selectively disrupts top-down adaptation to cognitive conflict in the Stroop test.

Sleep deprivation is known to exert detrimental effects on various cognitive domains, including attention, vigilance and working memory. Seemingly at odds with these findings, prior studies repeatedly failed to evidence an impact of prior sleep deprivation on cognitive interference in the Stroop test, a hallmark paradigm in the study of cognitive control abilities. The present study investigated further the effect of sleep deprivation on cognitive control using an adapted version of the Stroop test that allows to segregate top-down (attentional reconfiguration on incongruent items) and bottom-up (facilitated processing after repetitions in responses and/or features of stimuli) components of performance. Participants underwent a regular night of sleep or a night of total sleep deprivation before cognitive testing. Results disclosed that sleep deprivation selectively impairs top-down adaptation mechanisms: cognitive control no longer increased upon detection of response conflict at the preceding trial. In parallel, bottom-up abilities were found unaffected by sleep deprivation: beneficial effects of stimulus and response repetitions persisted. Changes in vigilance states due to sleep deprivation selectively impact on cognitive control in the Stroop test by affecting top-down, but not bottom-up, mechanisms that guide adaptive behaviours.

Age-related increases in Stroop interference: delineation of general slowing based on behavioral and white matter analyses.

The Stroop interference task is a widely used paradigm to examine cognitive inhibition, which is a key component of goal-directed behavior. With increasing age, reaction times in the Stroop interference task are usually slowed. However, to date it is still under debate if age-related increases in reaction times are merely an artifact of general slowing. The current study was conducted to investigate the role of general slowing, as measured by Trail-Making-Test-A, in age-related alterations of Stroop interference. We applied Diffusion Tensor Imaging (DTI) to determine the topography of neuronal networks underlying Stroop interference under control of general slowing. On the behavioral level, linear regression analysis demonstrated that age accounted for significant variance on Stroop interference, whereas TMT-A performance did not. Controlling for TMT-A, DTI based white matter analyses demonstrated a strong association of Stroop interference with integrity measures of genu of corpus callosum, bilateral anterior corona radiata, and bilateral anterior limb of capsula interna. These pathways are associated with frontal brain regions by either connecting the bilateral dorsolateral prefrontal cortex or the anterior cingulate cortex with frontal and subcortical regions or by containing fibers which are part of cortico-thalamic circuits that cross prefrontal regions. Importantly, results expand our knowledge of the neural basis of Stroop interference and emphasize the importance of white matter integrity of frontal pathways in the modulation of Stroop interference. Combining behavioral and DTI findings our results further suggest that cognitive inhibition, as measured by Stroop task, is a qualitatively distinct cognitive process that declines with age.

Stroop-interference effect in post-traumatic stress disorder.

To investigate the conflict processing in posttraumatic stress disorder (PTSD) patients, we conducted the classical Stroop task by recording event-related potentials. Although the reaction time was overall slower for PTSD patients than healthy age-matched control group, the Stroop-interference effect of reaction time did not differ between the two groups. Compared with normal controls, the interference effects of N 2 and N 450 components were larger and the interference effect of slow potential component disappeared in PTSD. These data indicated the dysfunction of conflict processing in individuals with PTSD.

Timbral brightness perception investigated through multimodal interference.

Brightness is among the most studied aspects of timbre perception. Psychoacoustically, sounds described as "bright" versus "dark" typically exhibit a high versus low frequency emphasis in the spectrum. However, relatively little is known about the neurocognitive mechanisms that facilitate these metaphors we listen with. Do they originate in universal magnitude representations common to more than one sensory modality? Triangulating three different interaction paradigms, we investigated using speeded classification whether intramodal, crossmodal, and amodal interference occurs when timbral brightness, as modeled by the centroid of the spectral envelope, and pitch height/visual brightness/numerical value processing are semantically congruent and incongruent. In four online experiments varying in priming strategy, onset timing, and response deadline, 189 total participants were presented with a baseline stimulus (a pitch, gray square, or numeral) then asked to quickly identify a target stimulus that is higher/lower, brighter/darker, or greater/less than the baseline after being primed with a bright or dark synthetic harmonic tone. Results suggest that timbral brightness modulates the perception of pitch and possibly visual brightness, but not numerical value. Semantically incongruent pitch height-timbral brightness shifts produced significantly slower reaction time (RT) and higher error compared to congruent pairs. In the visual task, incongruent pairings of gray squares and tones elicited slower RTs than congruent pairings (in two experiments). No interference was observed in the number comparison task. These findings shed light on the embodied and multimodal nature of experiencing timbre.

Meta-Analysis of Social Presence Effects on Stroop Task Performance.

In this paper, we conducted a meta-analytic review to examine the impact of social presence on individuals' performance on the Stroop task, shedding light on the cognitive processes underlying social facilitation. We followed PRISMA guidelines to identify and include 33 relevant studies in a multivariate random-effects meta-analysis. Our results show that social presence reliably modulates Stroop interference (a measure of cognitive control); specifically, participants exhibit lower Stroop interference when performing the task in the presence of others compared to performing it in isolation. We also found that the strength of the effect varies depending on the type of social presence: it is stronger with an attentive audience compared to an inattentive one, and null with an evaluative audience. Additionally, different features of the Stroop task itself moderate the effect; the effect is stronger for the classic version of the task compared to the semantic version, and for experiments that use mixed within-block trials compared to those with homogenous blocks. We also observed a negative relationship between the number of trials and the magnitude of the effect. Overall, these findings provide insights into the mechanisms by which the presence of others affects performance on the Stroop task, and how they align with social facilitation theories.

Does physical fitness affect cognitive functions differently across adulthood? An advantage of being older.

Introduction: There is a large interindividual variability in cognitive functioning with increasing age due to biological and lifestyle factors. One of the most important lifestyle factors is the level of physical fitness (PF). The link between PF and brain activity is widely accepted but the specificity of cognitive functions affected by physical fitness across the adult lifespan is less understood. The present study aims to clarify whether PF is basically related to cognition and general intelligence in healthy adults, and whether higher levels of PF are associated with better performance in the same or different cognitive functions at different ages. Methods: A sample of 490 participants (20-70 years) was analyzed to examine this relationship. Later, the sample was split half into the young to middle-aged group (YM; 20-45 years; n = 254), and the middleaged to older group (MO; 46-70 years; n = 236). PF was measured by a quotient of maximum power in a bicycle ergometry test PWC-130 divided by body weight (W/kg), which was supported by a self-reported level of PF. Cognitive performance was evaluated by standardized neuropsychological test batteries. Results: Regression models showed a relationship between PF and general intelligence (g-factor) and its subcomponents extracted using structural equation modeling (SEM) in the entire sample. This association was moderated by age, which also moderated some specific cognitive domains such as attention, logical reasoning, and interference processing. After splitting the sample into two age groups, a significant relationship was found between cognitive status, as assessed by the Mini Mental State Examination (MMSE), and PF in both age groups. However, apart from cognitive failures in daily life (CFQ), no other association between PF and specific cognitive functions was found in the YM group. In contrast, several positive associations were observed in the MO group, such as with selective attention, verbal memory, working memory, logical reasoning, and interference processing. Discussion: These findings show that middle-aged to older adults benefit more from PF than younger to middle-aged adults. The results are discussed in terms of the neurobiological mechanisms underlying the cognitive effects of PF across the lifespan. Clinical trial registration: https://clinicaltrials.gov/ct2/show/NCT05155397, identifier NCT05155397.

Failure of deactivation in bipolar disorder during performance of an fMRI adapted version of the Stroop task.

INTRODUCTION: Few studies have examined the functional brain correlates of the performance of the Stroop task in bipolar disorder (BD). It is also not known whether it is associated with failure of de-activation in the default mode network, as has been found in studies using other tasks. METHODS: Twenty-four BD patients and 48 age, sex and educationally estimated intellectual quotient (IQ) matched healthy subjects (HS) underwent a functional MRI during performance of the counting Stroop task. Task-related activations (incongruent versus congruent condition) and de-activations (incongruent versus fixation) were examined using whole-brain, voxel-based methodology. RESULTS: Both the BD patients and the HS showed activation in a cluster encompassing the left dorsolateral and ventrolateral prefrontal cortex and the rostral anterior cingulate cortex and supplementary motor area, with no differences between them. The BD patients, however, showed significant failure of de-activation in the medial frontal cortex and the posterior cingulate cortex/precuneus. CONCLUSIONS: The failure to find activation differences between BD patients and controls suggests that the 'regulative' component of cognitive control remains intact in the disorder, at least outside episodes of illness. The failure of de-activation found adds to evidence documenting trait-like default mode network dysfunction in the disorder.

Some further clarifications on age-related differences in the Stroop task: New evidence from the two-to-one Stroop paradigm.

Previous studies (Augustinova et al., Psychonomic Bulletin & Review, 25(2), 767-774, 2018; Li & Bosman, Aging, Neuropsychology, and Cognition, 3(4), 272-284, 1996) have shown that the larger Stroop effects reported in older adults is specifically due to age-related differences in the magnitude of response - and not semantic - conflict, both of which are thought to contribute to overall Stroop interference. However, the most recent contribution to the issue of the unitary versus composite nature of the Stroop effect argues that semantic conflict has not been clearly dissociated from response conflict in these or any other past Stroop studies, meaning that the very existence of semantic conflict is at present uncertain. To distinguish clearly between the two types of conflict, the present study employed the two-to-one Stroop paradigm with a color-neutral word baseline. This addition made it possible to isolate a contribution of semantic conflict that was independent of both response conflict and Stroop facilitation. Therefore, this study provides the first unambiguous empirical demonstration of the composite nature of Stroop interference - as originally claimed by multi-stage models of Stroop interference. This permitted the further observation of significantly higher levels of semantic conflict in older adults, whereas the level of response conflict in the present study remained unaffected by healthy aging - a finding that directly contrasts with previous studies employing alternative measures of response and semantic conflict. Two qualitatively different explanations of this apparent divergence across studies are discussed.

Reduced left dorsolateral prefrontal activation in problematic smartphone users during the Stroop task: An fNIRS study.

Introduction: The widespread use of smartphones has triggered concern over problematic smartphone use (PSPU), as well as the need to elucidate its underlying mechanisms. However, the correlation between cortical activation and deficient inhibitory control in PSPU remains unclear. Methods: This study examined inhibitory control using the color-word matching Stroop task and its cortical-activation responses using functional near-infrared spectroscopy (fNIRS) in college students with PSPU (n = 56) compared with a control group (n = 54). Results: At the behavioral level, Stroop interference, coupled with reaction time, was significantly greater in the PSPU group than in the control group. Changes in oxygenated hemoglobin (Oxy-Hb) signals associated with Stroop interference were significantly increased in the left ventrolateral prefrontal cortex, left frontopolar area, and bilateral dorsolateral prefrontal cortex (DLPFC). Moreover, the PSPU group had lower Oxy-Hb signal changes associated with Stroop interference in the left-DLPFC, relative to controls. Discussion: These results provide first behavioral and neuroscientific evidence using event-related fNIRS method, to our knowledge, that college students with PSPU may have a deficit in inhibitory control associated with lower cortical activation in the left-DLPFC.

Response competition better explains Stroop interference than does response exclusion.

Researchers debate whether Stroop interference from an incongruent word in color-naming response time is caused by response competition or by response exclusion. According to the former account, the interference reflects competition in lexical response selection during color name planning, whereas according to the latter, the interference reflects the removal of a motor program for the incongruent word from an articulatory buffer after planning. Here, numerical predictions about the magnitude of Stroop interference as a function of stimulus onset asynchrony were derived from these accounts. These predictions were then tested on representative data in the literature. Measures of goodness-of-fit showed that the numerical predictions of a response competition account are closer to the empirical data than those of the response exclusion account. These results indicate that response competition provides a better explanation of interference in naming than does response exclusion.

Is There Semantic Conflict in the Stroop Task?

This research addressed current controversies concerning the contribution of semantic conflict to the Stroop interference effect and its reduction by a single-letter coloring and cueing procedure. On the first issue, it provides, for the first time, unambiguous evidence for a contribution of semantic conflict to the (overall) Stroop interference effect. The reported data remained inconclusive on the second issue, despite being collected in a considerable sample and analyzed with both classical (frequentist) and Bayesian inferential approaches. Given that in all past Stroop studies, semantic conflict was possibly confounded with either response conflict (e.g., when semantic-associative items [SKYblue] are used to induce semantic conflict) or with facilitation (when color-congruent items [BLUEblue] are used as baseline to derive a magnitude for semantic conflict), its genuine contribution to the Stroop interference effect is the most critical result reported in the present study. Indeed, it leaves no doubt - in complete contrast to dominant single-stage response competition models (e.g., Roelofs, 2003) - that selection occurs at the semantic level in the Stroop task. The immediate implications for the composite (as opposed to unitary) nature of the Stroop interference effect and other still unresolved issues in the Stroop literature are outlined further.

Selective Attention and Information Processing Speed in Graves' Disease: Stroop Interference Effect.

Background Cognitive functions are affected by thyroid hormones. In this study, we aimed to investigate the selective attention and information processing speed in thyrotoxic Graves' disease. Methodology This study was conducted among 40 patients with thyrotoxic Graves' disease and age and gender-matched 40 healthy controls. Stroop Color and Word test were applied to healthy controls once and to patients with Graves' disease during thyrotoxic and euthyroid periods. Stroop interference effect was calculated. Results The mean age was 34.67 ± 11 in the Graves' group and 34.72 ± 9.16 in the control group (p > 0.05). The number of errors and self-corrections in Stroop Color and Word test was higher in patients with thyrotoxic Graves' disease than both patients with euthyroid Graves' disease and healthy controls (p < 0.05). Stroop interference effect was significantly longer in patients with thyrotoxic Graves' disease than both patients with euthyroid Graves' disease and healthy controls (p < 0.05). All parameters obtained from the Stroop Color and Word test including errors, self-corrections, and Stroop interference effect were similar in patients with euthyroid Graves' disease and healthy controls. Conclusions Selective attention was impaired and information processing speed was slow in patients with thyrotoxic Graves' disease, and these findings were associated with age and educational level. After becoming euthyroid through antithyroid medication, these pathological findings returned to normal levels. Additionally, Stroop interference effect was significantly decreased when patients with Graves' disease became euthyroid.