Cognition in Euthymic Patients with Bipolar Disorder: Do Not Forget to Account for Anxiety!

Purpose: Despite the high prevalence of anxiety disorders in BD and its known impact on cognitive performance, the presence and severity of anxious symptoms is not systematically evaluated in studies on cognition in BD. Our aim was to determine if attention and/or inhibition of cognitive interference in euthymic patients with type I Bipolar Disorder (BD-I) is affected by symptoms of anxiety. Patients and Methods: Eighty-seven euthymic BD-I patients were included. Patients with comorbidities other than Generalized Anxiety Disorder (GAD) or Panic Disorder (PD) were excluded. State anxiety was measured with the Brief Inventory of Anxious Responses and Situations (ISRA-B). Subjective cognitive performance was evaluated with the COBRA scale, attention with the Digit-Span Forward task and inhibition of cognitive interference was assessed with the StroopTest interference score. Multiple linear regression models were used to test if anxious symptoms were associated with attention or inhibition of cognitive interference, considering other known contributors for cognitive impairment. Results: Attention was unaffected by anxiety symptoms, but the overall regression for inhibition of cognitive interference was significant: years of schooling (ß=1.12, p = 0.001), cognitive complaints (ß=0.44, p = 0.008), and anxiety (ß=-0.21, p = 0.017) explained 15% of the interference score of the Stroop test (R2 = 0.15). Conclusion: Beyond residual affective symptoms, anxious symptoms seem to affect inhibition of cognitive interference. We recommend routine testing of anxiety when considering cognitive evaluations, especially when screening for cognitive deficits.

Enhanced Cognitive Inhibition in Table Tennis Athletes: Insights from Color-Word and Spatial Stroop Tasks.

The ability to inhibit conflicting information is pivotal in the dynamic and high-speed context of fast-ball sports. However, the behavioral and electrophysiological characteristics underlying the cognitive inhibition processes associated with table tennis expertise remain unexplored. This study aims to bridge these research gaps by utilizing the color-word Stroop task and the spatial Stroop task alongside event-related potential (ERP) measurements to investigate domain-general and domain-specific cognitive inhibition among table tennis athletes. The study involved a total of 40 participants, including 20 table tennis athletes (11 males and 9 females; mean age 20.75 years) and 20 nonathletes (9 males and 11 females; mean age 19.80 years). The group differences in the Stroop effect on behavioral outcomes and ERP amplitudes were compared within each task, respectively. In the color-word Stroop tasks, athletes exhibited smaller incongruent-related negative potential amplitudes (Ninc; 300-400 ms; p = 0.036) and a diminished Stroop effect on late sustained potential amplitudes (LSP; 500-650 ms; p = 0.028) than nonathletes, although no significant differences were observed in behavioral outcomes (p > 0.05). Conversely, in the spatial Stroop tasks, athletes not only responded more swiftly but also exhibited reduced Stroop effects on both LSP amplitudes (350-500 ms; p = 0.004) and reaction times (p = 0.002) relative to nonathletes. These findings suggest that table tennis athletes excel in cognitive inhibition in the context of both domain-general and domain-specific tasks, particularly exhibiting enhanced performance in tasks that are closely aligned with the demands of their sport. Our results support the neural efficiency hypothesis and improve our understanding of the interactions between cognitive functions and table tennis expertise.

The Influence of Manipulating and Accentuating Task-Irrelevant Information on Learning Efficiency: Insights for Cognitive Load Theory.

The paper endorses Cognitive Load Theory and offers insights into the characterization of the mechanisms underlying extraneous cognitive load and their impact on basic learning. Students were asked to learn associations between eight base-code words and eight digits, based on an example, and to rapidly apply their new knowledge in a test section. Two groups of 60 university students participated in two experiments. The study was implemented as two distinct experiments, one using color names (e.g., blue, yellow) and the other using color-related word concepts (e.g., sky, banana) for stimulation. Each experiment had two conditions that manipulated the location and salience of task-irrelevant color information (extraneous cognitive load) and its congruity with the digits' corresponding base-code words. Findings indicated extraneous cognitive load has the potential to both sustain and undermine learning processes by varying the overall cognitive load, with gains and costs in learning efficiency resulting from essentially different processing scenarios.

Distributional analyses reveal the polymorphic nature of the Stroop interference effect: It's about (response) time.

The study addressed the still-open issue of whether semantic (in addition to response) conflict does indeed contribute to Stroop interference (which along with facilitation contributes to the overall Stroop effect also known as Congruency effect). To this end, semantic conflict was examined across the entire response time (RT) distribution (as opposed to mean RTs). Three (out of four) reported experiments, along with cross-experimental analyses, revealed that semantic conflict was absent in the participants' faster responses. This result characterizes Stroop interference as a unitary phenomenon (i.e., driven uniquely by response conflict). When the same participants' responses were slower, Stroop interference became a composite phenomenon with an additional contribution of semantic conflict that was statistically independent of both response conflict and facilitation. While the present findings allow us to account for the fact that semantic conflict has not been consistently found in past studies, further empirical and theoretical efforts are still needed to explain why exactly it is restricted to longer responses. Indeed, since neither unitary nor composite models can account for this polymorphic nature of Stroop interference on their own, the implications for the current state of theory are outlined.

Conflict monitoring and emotional processing in 3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine users - A comparative neurophysiological study.

In stimulant use and addiction, conflict control processes are crucial for regulating substance use and sustaining abstinence, which can be particularly challenging in social-affective situations. Users of methamphetamine (METH, "Ice") and 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") both experience impulse control deficits, but display different social-affective and addictive profiles. We thus aimed to compare the effects of chronic use of the substituted amphetamines METH and MDMA on conflict control processes in different social-affective contexts (i.e., anger and happiness) and investigate their underlying neurophysiological mechanisms. For this purpose, chronic but recently abstinent users of METH (n = 38) and MDMA (n = 42), as well as amphetamine-naïve healthy controls (n = 83) performed an emotional face-word Stroop paradigm, while event-related potentials (ERPs) were recorded. Instead of substance-specific differences, both MDMA and METH users showed smaller behavioral effects of cognitive-emotional conflict processing (independently of emotional valence) and selective deficits in emotional processing of anger content. Both effects were underpinned by stronger P3 ERP modulations suggesting that users of substituted amphetamines employ altered stimulus-response mapping and decision-making. Given that these processes are modulated by noradrenaline and that both MDMA and METH use may be associated with noradrenergic dysfunctions, the noradrenaline system may underlie the observed substance-related similarities. Better understanding the functional relevance of this currently still under-researched neurotransmitter and its functional changes in chronic users of substituted amphetamines is thus an important avenue for future research.

The contribution of difficulty of an irrelevant task to task conflict.

In the standard colour-word Stroop task, participants are presented with colour words and required to respond to their colour while ignoring their meaning. Two types of conflict might occur in such experiments: information conflict and task conflict. Information conflict reflects the processing of two contradicting pieces of information and is indicated by shorter reaction times (RTs) in congruent than in incongruent trials. Task conflict reflects the additional effort associated with performing two tasks, as opposed to one, and is indicated by shorter RTs in neutral trials than in congruent trials (termed reverse facilitation). While information conflict is commonly seen in Stroop and Stroop-like tasks, task conflict is rarely observed. In the present study, participants were presented with coloured segments that, by applying Gestalt principles, could be perceived as colour words. We found that incongruent trials were slower than congruent trials, suggesting that participants successfully perceived the colour words, which led to involuntary reading. In addition, reversed facilitation was found so that neutral trials (i.e., trials that only consist of one task) were faster than congruent trials (as well as incongruent trials; both consist of two tasks). The presence of both interference from the incongruent trials and reverse facilitation suggests that involuntary reading could also occur in scenarios requiring cognitive effort.

Assessment of ADHD Subtypes Using Motion Tracking Recognition Based on Stroop Color-Word Tests.

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder known for its significant heterogeneity and varied symptom presentation. Describing the different subtypes as predominantly inattentive (ADHD-I), combined (ADHD-C), and hyperactive-impulsive (ADHD-H) relies primarily on clinical observations, which can be subjective. To address the need for more objective diagnostic methods, this pilot study implemented a Microsoft Kinect-based Stroop Color-Word Test (KSWCT) with the objective of investigating the potential differences in executive function and motor control between different subtypes in a group of children and adolescents with ADHD. A series of linear mixture modeling were used to encompass the performance accuracy, reaction times, and extraneous movements during the tests. Our findings suggested that age plays a critical role, and older subjects showed improvements in KSWCT performance; however, no significant divergence in activity level between the subtypes (ADHD-I and ADHD-H/C) was established. Patients with ADHD-H/C showed tendencies toward deficits in motor planning and executive control, exhibited by shorter reaction times for incorrect responses and more difficulty suppressing erroneous responses. This study provides preliminary evidence of unique executive characteristics among ADHD subtypes, advances our understanding of the heterogeneity of the disorder, and lays the foundation for the development of refined and objective diagnostic tools for ADHD.

Resting Stroop task: Evidence of task conflict in trials with no required response.

In the typical Stroop task, participants are presented with color words written in different ink colors and are asked to respond to their color. It has been suggested that the Stroop task consists of two main conflicts: information conflict (color vs. word naming) and task conflict (respond to color vs. read the word). In the current study, we developed a novel task that includes both Response trials (i.e., trials in which a response is required) and Rest trials (i.e., trials in which no response is required or available) and investigated the existence of both information and task conflicts in Rest trials. We found evidence for task conflict in Response and also in Rest trials, while evidence for information conflict was only observed in Response trials. These results are in line with a model of task conflict that occurs independently of and prior to information conflict in the Stroop task.

The Stroop effect and mental imagery.

The classic Stroop task is very simple: you have to name the color of words printed on a page. If these words are color words (like "red" or "blue"), where the color named and the color it is printed in are different (say, "red" printed in blue), the reaction time increases significantly. My aim is to argue that the existing psychological explanations of the Stroop effect need to be supplemented. The Stroop effect is not exclusively about access to motor control. It is also, to a large extent, about interferences in perceptual processing. To put it briefly, reading the color word triggers-laterally and automatically-visual imagery of the color and this interferes with the processing of the perceived color of the word. In other words, the Stroop effect is to a large extent a sensory phenomenon, and it has less to do with attention, conflict monitoring, or other higher-level phenomena.

Congruency of color-sound crossmodal correspondence interacts with color and sound discrimination depending on color category.

People occasionally associate color (e.g., hue) with sound (e.g., pitch). Previous studies have reported color-sound associations, which are examples of crossmodal correspondences. However, the association between both semantic and perceptual factors with color/sound discrimination in crossmodal correspondence remains unclear. To clarify this, three psychological experiments were conducted, where Stroop tasks were used to assess automatic process on the association. We focused on the crossmodal correspondence between color (Experiment 1)/color word (Experiment 2) and sound. Participants discriminated the color/word or the sound presented simultaneously. The results showed the color-sound bidirectional enhancement/interference of the response by certain associations of the crossmodal correspondence (blue-drop and yellow-shiny) in both experiments. These results suggest that these Stroop effects were caused by the semantic factor (color category) and the perceptual factor (color appearance) was not necessary for the current results. In Experiment 3, response modulation by color labeling was investigated to clarify the influence of subjective labeling. Participants labeled a presented ambiguous color, which was a hue specification between two specific colors, by listening to the sound. The results revealed that the Stroop effect was caused only when the presented color was classified as the color related to the presented sound. This showed that subjective labeling played a role in the regulation of the effect of crossmodal correspondences. These findings should contribute to the explanation of crossmodal correspondences through semantic mediation.

Comparison of Frequentist and Bayesian Statistics for Studying Unconscious Perception: Differences Between Null Awareness Dissociation and Relative Sensitivity Dissociation.

For unconscious perception research, Bayesian statistics are more appropriate for assessing null awareness of masked stimuli than traditional (frequentist) statistics. This assertion is based mostly upon the theoretical features of Bayesian statistics and modeling studies. To further assess the potential advantages, we compared frequentist and Bayesian statistical tests in a masked Stroop priming experiment in which the prime stimuli were presented at varying degrees of visibility. A novel contribution was to compare a null awareness dissociation approach (i.e., stimulus awareness = 0) to a relative sensitivity approach (indirect or priming effects > direct effects) for the same data. From a null awareness perspective, the frequentist t-tests for the Stroop effect (i.e., perception) for the briefest display conditions had non-significant outcomes. Similar Bayesian t-tests were inconclusive. In contrast, the relative sensitivity dissociation approach was more interpretable, with strong evidence against unconscious perception from a single Bayesian t test. For the longer display conditions, both statistical approaches suggested large conscious perception effects. We conclude that the utility of Bayesian statistics is highly dependent upon the type of dissociation approach, with a relative sensitivity approach being more straightforward to interpret than a null awareness approach.

Target-distractor correlation does not imply causation of the Stroop effect.

In the Stroop task, the identities of the targets (e.g., colours) and distractors (e.g., words) used are often correlated. For example, in a list in which 4 words and 4 colours are combined to form 16 stimuli, each of the 4 congruent stimuli is typically repeated 3 times as often as each of the 12 incongruent stimuli. Some accounts of the Stroop effect suggest that in this type of list, often considered as a baseline because of the matching proportion of congruent and incongruent stimuli (50%), the word dimension actually receives more attention than it does in an uncorrelated list in which words and colours are randomly paired. This increased attention would be an important determinant of the Stroop effect in correlated situations, an idea supported by the observation that higher target-distractor correlation lists are associated with larger Stroop effects. However, because target-distractor correlation tends to be confounded with congruency proportion in common designs, the latter may be the crucial factor, consistent with accounts that propose that attention is adapted to the list's congruency proportion. In four experiments, we examined the idea that target-distractor correlation plays a major role in colour-word Stroop experiments by contrasting an uncorrelated list with a correlated list matched on relevant variables (e.g., congruency proportion). Both null hypothesis significance testing and Bayesian analyses suggested equivalent Stroop effects in the two lists, challenging accounts based on the idea that target-distractor correlations affect how attention is allocated in the colour-word Stroop task.

Control over emotional facial expressions: Evidence from facial EMG and ERPs in a Stroop-like task.

Facial expressions carry important social signals that must be precisely regulated despite potentially conflicting demands on veridicality, communicative intent, and the social situation. In a sample of 19 participants we investigated the challenges of deliberately controlling two facial expressions (smiles and frowns) by the emotional congruency with the expressions of adult and infant counterparts. In a Stroop-like task requiring participants' deliberate expressions of anger or happiness, we investigated the impact of task-irrelevant background pictures of adults and infants showing negative, neutral, or positive facial expressions. Participants' deliberate expressions were measured with electromyogram (EMG) of the M. zygomaticus major and M. corrugator supercilii. The latencies of EMG onsets revealed similar congruency effects for smiles and frowns with significant facilitation and inhibition components relative to the neutral condition. Interestingly, the facilitation effect for frown responses by negative facial expressions was significantly smaller vis a vis infant as compared to adult background faces. This diminished facilitation of frowns by infant's expressions of distress may relate to the activation of caregiver behavior or empathy. We investigated the neural correlates of the observed performance effects by recording event-related-potentials (ERPs). Increased amplitudes in ERP components were observed in incongruent relative to neutral conditions, revealing interference effects on both types of deliberate facial expressions, at different processing stages, namely, structural facial encoding (N170), conflict monitoring (N2), to semantic analysis (N400).

Cognitive effort and active inference.

This paper aims to integrate some key constructs in the cognitive neuroscience of cognitive control and executive function by formalising the notion of cognitive (or mental) effort in terms of active inference. To do so, we call upon a task used in neuropsychology to assess impulse inhibition-a Stroop task. In this task, participants must suppress the impulse to read a colour word and instead report the colour of the text of the word. The Stroop task is characteristically effortful, and we unpack a theory of mental effort in which, to perform this task accurately, participants must overcome prior beliefs about how they would normally act. However, our interest here is not in overt action, but in covert (mental) action. Mental actions change our beliefs but have no (direct) effect on the outside world-much like deploying covert attention. This account of effort as mental action lets us generate multimodal (choice, reaction time, and electrophysiological) data of the sort we might expect from a human participant engaging in this task. We analyse how parameters determining cognitive effort influence simulated responses and demonstrate that-when provided only with performance data-these parameters can be recovered, provided they are within a certain range.

Cursor movements to targets labelled "stop": a kinematic analysis.

The label 'Stop' potentially generates conflict-signifying important corrective action, or a warning not to touch. To examine potential conflict between an incongruent label (i.e. STOP) and an imperative command (i.e. MOVE!), 18 participants used a computer mouse to move a crosshair cursor to targets with superimposed labels. Trials systematically varied Imperative (blank or MOVE!), Label (+GO + or STOP) and movement Distance. Kinematic analyses examined response latency, movement duration and accuracy. Incongruent labels had little impact upon response latencies, but they affected cursor deceleration and the variability of cursor placement. Although reading is assumed to be obligatory, the impact of written labels is not immediate, instead affecting cursor deceleration. Indeed, responses to controls labelled STOP were less accurate than those labelled + GO+. As labelled interfaces can create error versus command confusions, enhancing the discriminability of controls to afford more obvious visible cues as to method of use is recommended. Practitioner summary: Emergency stop and shutdown controls can cause response conflict as their labels signify both urgent corrective actions and 'don't touch'. Response conflict caused by confusing superimposed labels is resolved as cursors near the target control and may result in reduced movement accuracy. Prior warnings may influence resolution of response conflict. Abbreviations: Hz: Hertz; M: Mean; ms: millisecond; mm: millimetre; S: second; SD: Standard Deviation; SE: Standard Error; USB: Universal Serial Bus.

A shortened Stroop test to identify covert hepatic encephalopathy and predict overt hepatic encephalopathy in patients with cirrhosis.

BACKGROUND: Covert hepatic encephalopathy (CHE) adversely affects the clinical outcomes of patients with cirrhosis but remains largely undiagnosed and untreated. Although the Stroop test is a useful method for CHE detection, a faster, simpler, and more accurate test is required to diagnose CHE. This prospective study aimed to develop a new shortened Stroop test that can detect CHE and predict overt hepatic encephalopathy (OHE) in Japanese patients with cirrhosis. METHODS: Patients who underwent neuropsychological tests (NPT) and the Stroop test between November 2018 and December 2021 were enrolled and followed until OHE occurrence or March 2022. The discriminative ability of various run combinations in the off and on states to detect CHE was evaluated using the area under the receiver-operating characteristic curve (AUC) and compared with that of the total Stroop test time. RESULTS: Among the 227 eligible patients, the On1-2Time cutoff value of 44.4 s had a comparable discriminative ability with the total Stroop test time to detect CHE, with an AUC of 0.791, a sensitivity of 0.827, and a specificity of 0.685. During a median follow-up period of 16 months, 37 patients developed OHE. On1-2Time ≥ 44.4 s (hazard ratio [HR], 3.93; 95% confidence interval [CI] 1.36-11.36) and serum albumin levels (HR, 0.28; 95% CI 0.11-0.67) were independently associated with OHE occurrence. CONCLUSIONS: The shortened Stroop test (On1-2Time) is equivalent to the total Stroop test not only for identifying CHE but also for estimating the risk of progression to OHE.

Gender differences in professional drivers' fatigue level measured with BAlert mobile app: A psychophysiological, time efficient, accessible, and innovative approach to fatigue management.

Addressing fatigue is useful in a variety of scenarios and activities. Fatigue has recently been studied from a psychophysiological standpoint. As a result, the expression and impact of peripheral and central fatigue has been evaluated. Driving is one occupation where tiredness has disastrous consequences. BAlert is a smartphone app that approaches exhaustion with psychophysiological measures. More specifically, it evaluates the level of fatigue via heart rate variability (HRV) data and the cognitive compromise via Stroop effect. The goal of this study is to determine if there are gender differences in fatigue levels among professional drivers using the BAlert app. Statistically significant differences were found in the number of hours awake, in different parameters of HRV (AVNN, PNN50, RMSSD, and SDNN), in the level of stress, as well as in the cognitive response evaluated through the app. The results are discussed and their implications for the management of work fatigue are presented.

Incompatibility Influences Cursor Placement When Pointing to Images of Cups.

OBJECTIVE: As images are used within graphical user interfaces to signify menu selection, it is important to understand how image properties can influence cursor placement online. BACKGROUND: Objects have multiple dimensions that create potential ambiguity and Stroop-like confusions for the operator if a previously habitual response conflicts with the required response. METHODS: To examine the impact of compatibility and other contextual factors, 41 participants used a computer Mouse or touch screen to place the cursor upon images of full or empty cups that varied in size, and direction of handle. RESULTS: Cursor placements took longer using the Mouse than touch screen. Although participants were placing the cursor on images, the size of the cup, whether it was empty or full, and the handle orientation interacted in their effects upon response duration and cursor placement. The effects of cup size reversed for empty cups or those with incompatible handles. CONCLUSION: Context can influence cursor placement. Perceived spillability influenced precision requirements, and the cup handle can serve as target or a flanking distractor. APPLICATION: Image content can influence screen hotspots. As performance can change with cup spillability, this bodes well for attempts to detect intent from cursor trajectories.

Revisiting congruency effects in the working memory Stroop task.

The working memory Stroop task is to name the color of a rectangular patch with keypress while holding a color word in working memory. Previous studies using this variant of the Stroop task have shown that congruency between the color patch and the color word significantly affects both color naming and working memory, with the worsening of task performance when the color patch is semantically incongruent rather than congruent with the color word. However, it remains unclear with regard to cognitive mechanisms underlying such congruency effects in the working memory Stroop task. By including a control condition among the congruent and incongruent conditions in a working memory Stroop task, the present study showed that nearly all of the working memory Stroop effect can be facilitation, and that interference, if present, is markedly smaller than facilitation in this form of the Stroop effect. There was also a critical contrast between the working memory and classic Stroop effects in terms of facilitation and interference, with larger facilitation and smaller interference in the working memory Stroop effect than in the classic Stroop effect. Moreover, working memory for a color word can be either facilitated or interfered with by the perceptual judgment (color naming) of an interposed color patch during the retention interval, depending on whether the color patch is semantically congruent or incongruent with the color word. Together, these results suggest that both facilitation and interference mechanisms can contribute to the overall congruency effects in the working memory Stroop task.

Abnormal EEG signal energy in the elderly: A wavelet analysis of event-related potentials during a stroop task.

BACKGROUND: Previous work showed that elderly with excess in theta activity in their resting state electroencephalogram (EEG) are at higher risk of cognitive decline than those with a normal EEG. By using event-related potentials (ERP) during a counting Stroop task, our prior work showed that elderly with theta excess have a large P300 component compared with normal EEG group. This increased activity could be related to a higher EEG signal energy used during this task. NEW METHOD: By wavelet analysis applied to ERP obtained during a counting Stroop task we quantified the energy in the different frequency bands of a group of elderly with altered EEG. RESULTS: In theta and alpha bands, the total energy was higher in elderly subjects with theta excess, specifically in the stimulus categorization window (258-516 ms). Both groups solved the task with similar efficiency. COMPARISON WITH EXISTING METHODS: The traditional ERP analysis in elderly compares voltage among conditions and groups for a given time window, while the frequency composition is not usually examined. We complemented our previous ERP analysis using a wavelet methodology. Furthermore, we showed the advantages of wavelet analysis over Short Time Fourier Transform when exploring EEG signal during this task. CONCLUSIONS: The higher EEG signal energy in ERP might reflect undergoing neurobiological mechanisms that allow the elderly with theta excess to cope with the cognitive task with similar behavioral results as the normal EEG group. This increased energy could promote a metabolic and cellular dysregulation causing a greater decline in cognitive function.