Always on guard: test of high vs. low control conditions in obsessive-compulsive disorder patients

Proactive control affects task conflict beyond contingency learning

Various models of the Stroop task suggest that proactive task control adaptation accounts for the modulation of task conflict in different conditions of the Stroop task, for example, when task conflict is very frequent or very infrequent. Other researchers have argued that a contingency learning of colour-word associations is the main contributor to the modulations of the Stroop effect. In this work, we constructed a design that controls for confounds that are suspected to rule out the role of control adaptation in the Stroop task. We focused on one type of conflict-task conflict and tested whether colour-naming of neutral-words (where task conflict is present) differed from colour-naming of neutral-symbols (where task conflict is not present) in four different conditions: mostly words-congruent, mostly words-incongruent, mostly words-neutral, or mostly non-words-shape. Importantly, the conditions used for the task conflict marker were identical in all four conditions. We found that the marker of task conflict (reaction time [RT] for neutral-words > RT for neutral-symbols) was significant in the mostly non-words-shape condition, where proactive task control is relaxed, but not in the mostly words conditions, where proactive task control is activated, with no difference between these three words conditions. These findings suggest that control adaptation is the main contributor to the modulations of the Stroop effect. The relevance of the results to the current literature is discussed and the results are explained in light of the proactive control-task conflict (PC-TC) model.

High treatment resistance is associated with lower performance in the Stroop test in patients with obsessive-compulsive disorder

Around 50% of the patients with obsessive-compulsive disorder (OCD) are resistant to treatment, and patients with OCD show alterations in a broad range of cognitive abilities. The present study investigated the links between treatment-resistance, executive and working memory abilities, and the severity of OCD symptoms among 66 patients with OCD. The patients performed seven tests gauging their executive functions and working memory and filled in questionnaires for OCD severity and insight into their pathology. In addition, the executive and working memory abilities of a subset of these patients were compared with those of individually matched control participants. In contrast with previous studies, patients' treatment resistance was evaluated by considering the clinical outcomes of all the treatments that they received during the course of their disease. Higher treatment resistance was associated with lower performance in one particular executive test, the Stroop test, which assessed patients' ability to inhibit prepotent/automatic responses. Older age and more severe OCD symptoms were also associated with higher treatment resistance. Regardless of OCD severity, the patients displayed small to moderate deficits across most components of executive functions compared to control participants. Interestingly, patients with OCD took more time than control participants to perform speeded neuropsychological tests but never made more errors. Altogether, this study shows that the treatment-resistance of patients with OCD may be reliably quantified over the course of years and treatments using Pallanti and Quercioli's (2006) treatment resistance-related scales. The data suggest that the Stroop test could be used clinically to anticipate treatment outcomes in to-be-treated patients.

Effects of a three-week executive control training on adaptation to task difficulty and emotional interference

Intact executive functions are characterized by flexible adaptation to task requirements, while these effects are reduced in internalizing disorders. Furthermore, as executive functions play an important role in emotion regulation, deficits in executive functions may contribute to symptom generation in psychological disorders through increased emotional interference. Thus, the present study investigated transfer effects of a three-week executive control training on adaptation to task difficulty and emotional interference in healthy participants (n = 24) to further explore the training's suitability for clinical application. To assess the adaptation to task difficulty, the proportion congruency effect on behavioral data (response times, error rates) and ERP measures (N2, CRN) was assessed in a flanker task with varying frequency of incompatible trials (25%, 75%). To quantify emotional interference, flanker stimuli were superimposed on neutral or negative pictures. Replicating previous results, the training increased interference control as indexed by decreased response times and errors rates, increased N2 amplitude and decreased CRN amplitude in incompatible trials after training. Proportion congruency effects were weaker than expected and not affected by the training intervention. The training lead to a shift in the time-point of emotional interference: before training negative pictures lead to a reduction in CRN amplitude, while after training this reduction was observed for the N2. This pattern illustrates that the training leads to a change in task processing mode from predominant response-related cognitive control to predominant stimulus-related cognitive control (N2), indicating a proactive processing mode.

Error-Related Brain Activity in Patients With Obsessive-Compulsive Disorder and Unaffected First-Degree Relatives: Evidence for Protective Patterns

Background

Indicators of increased error monitoring are associated with obsessive-compulsive disorder (OCD), as shown in electroencephalography and functional magnetic resonance imaging studies. As most studies used strictly controlled samples (excluding comorbidity and medication), it remains open whether these findings extend to naturalistic settings. Thus, we assessed error-related brain activity in a large, naturalistic OCD sample. We also explored which activity patterns might qualify as vulnerability endophenotypes or protective factors for the disorder. To this aim, a sample of unaffected first-degree relatives of patients with OCD was also included.

Methods

Participants (84 patients with OCD, 99 healthy control participants, and 37 unaffected first-degree relatives of patients with OCD) completed a flanker task while blood oxygen level–dependent responses were measured with functional magnetic resonance imaging. Aberrant error-related brain activity in patients and relatives was identified.

Results

Patients with OCD showed increased error-related activity in the supplementary motor area and within the default mode network, specifically in the precuneus and postcentral gyrus. Unaffected first-degree relatives showed increased error-related activity in the bilateral inferior frontal gyrus.

Conclusions

Increased supplementary motor area and default mode network activity in patients with OCD replicates previous studies and might indicate excessive error signals and increased self-referential error processing. Increased activity of the inferior frontal gyrus in relatives may reflect increased inhibition. Impaired response inhibition in OCD has been demonstrated in several studies and might contribute to impairments in suppressing compulsive actions. Thus, increased inferior frontal gyrus activity in the unaffected relatives of patients with OCD may have contributed to protection from symptom development.

Intact capacity for implicit learning in obsessive-compulsive disorder

BACKGROUND AND OBJECTIVES

Individuals with OCD tend to rely on explicit processing when performing implicit learning tasks. However, it is unclear whether this tendency reflects impaired capacity for implicit processing or a preference toward explicit processing. We sought to use a psychometrically valid task to examine the hypothesis that individuals with OCD have intact capacity for implicit learning.

METHODS

Twenty-four participants with OCD and 24 non-psychiatric controls completed a modified artificial grammar learning task where acquisition and retrieval of the underlying grammatical rules are considered strictly implicit. In an exploratory condition designed to examine the effect of nudging participants toward controlled processing, 12 participants in each group were told that the stimuli presented at acquisition were composed according to grammatical rules and were encouraged to identify these rules.

RESULTS

As predicted, participants with OCD acquired and expressed knowledge of the grammatical rule, demonstrating intact capacity for implicit learning, with no differences found between the OCD and controls on the extent of implicit learning. The exploratory intentional learning instructions had no effect, as participants in this condition were unable to adhere to the instructions, supporting the robust implicit nature of the artificial grammar learning task.

LIMITATIONS

The relatively small sample size did not allow comparisons between OCD symptom subtypes.

CONCLUSIONS

Our results provide evidence for intact implicit learning in OCD, and challenge previous studies suggesting a general deficiency in implicit learning in OCD.

Impaired test performance yet spared neurocognitive functioning in individuals with obsessive-compulsive disorder: the role of performance mediators

INTRODUCTION

Although most studies report neurocognitive deficits in patients with obsessive-compulsive disorder (OCD), important exceptions exist, highlighting the possible role of mediators (e.g., poor motivation). This study investigated neurocognitive functioning and potential influences affecting performance in OCD.

METHODS

Forty-three participants (13 OCD patients, 30 healthy controls) were assessed using a battery of neurocognitive tests. During the assessment, the examiner completed the Impact on Performance Scale (IPS) which measures variables that may impact neurocognitive performance.

RESULTS

Pooled neurocognitive performance was lower in OCD patients versus healthy controls at a moderate effect size. Patients performed more poorly on the IPS, particularly the Well-Being During Assessment subscale. Performance differences across the two groups were attenuated to a non-significant small-to-medium effect when the IPS was entered as a covariate. A total of 34% of patients showed scores greater than one standard deviation below the mean compared to 9.63% in healthy individuals. Yet, when a conservative impairment criterion (≥2 standard deviations below the mean) was applied, less than 10% of patients displayed deficits.

CONCLUSIONS

Neurocognitive impairment in OCD is likely exaggerated. In addition to considering important mediators researchers should report the percentage of participants displaying performance deficits rather than mean group differences alone; the latter obscures the high percentage of patients without impairment and thus may unduly foster stigma in this population.

Cognitive control is quickly adapted to actual task requirements despite misleading context cues-Evidence from the N2, CRN, and ERN

Cognitive control is flexibly adapted to task requirements in healthy individuals. Medio-frontal negativities in the event-related potential of the electroencephalogram can serve as indicators of cognitive control. With increasing conflict frequency, stimulus-locked control, as indexed by the N2, is increased and response-locked control, as indexed by the correct-related negativity, is reduced. On the behavioral level, this shift is associated with improved conflict resolution as evident in reduced response times and error rates in incompatible trials and a reduced response time congruency effect. Cognitive control adaptation might be implemented through experience-based task sets specifying advantageous processing strategies. Here, we investigated whether the cognitive control task set will be sustained when coupled with a contextual cue, even when the initial task requirements are no longer present. A flanker task with two conflict frequency conditions (25% incompatible and 75% incompatible trials) was presented. In the training phase, the conflict frequency conditions were paired with a distinct context cue (i.e., background color). In the test phase, the previously associated cues were again presented, but conflict frequency was identical in both conditions (50% incompatible trials). Although typical cognitive control adaptation was observed in the training phase on the behavioral and event-related potentials level, this pattern was not sustained in the test phase. Thus, the present study provides further evidence that cognitive control is flexibly adapted to task requirements even in the presence of misleading cues.

Stopping a Response When You Really Care about the Action: Considerations from a Clinical Perspective

Response inhibition, whether reactive or proactive, is mostly investigated in a narrow cognitive framework. We argue that it be viewed within a broader frame than the action being inhibited, i.e., in the context of emotion and motivation of the individual at large. This is particularly important in the clinical domain, where the motivational strength of an action can be driven by threat avoidance or reward seeking. The cognitive response inhibition literature has focused on stopping reactively with responses in anticipation of clearly delineated external signals, or proactively in limited contexts, largely independent of clinical phenomena. Moreover, the focus has often been on stopping efficiency and its correlates rather than on inhibition failures. Currently, the cognitive and clinical perspectives are incommensurable. A broader context may explain the apparent paradox where individuals with disorders characterised by maladaptive action control have difficulty inhibiting their actions only in specific circumstances. Using Obsessive Compulsive Disorder as a case study, clinical theorising has focused largely on compulsions as failures of inhibition in relation to specific internal or external triggers. We propose that the concept of action tendencies may constitute a useful common denominator bridging research into motor, emotional, motivational, and contextual aspects of action control failure. The success of action control may depend on the interaction between the strength of action tendencies, the ability to withhold urges, and contextual factors.

Affordances, response conflict, and enhanced-action tendencies in obsessive-compulsive disorder: an ERP study

BACKGROUND

Obsessive-compulsive disorder (OCD) is characterized by recurrent, intrusive thoughts and/or behaviors. OCD symptoms are often triggered by external stimuli. Therefore, it has been suggested that difficulty inhibiting responses to stimuli associated with strong action tendencies may underlie symptoms. The present electrophysiological study examined whether stimuli evoking a strong automatic response are associated with enhanced action tendencies in OCD participants relative to healthy controls.

METHODS

The lateralized readiness potential (LRP) and the N2 event-related potential (ERP) components were used as measures of action tendencies and inhibition, respectively. ERPs were recorded while 38 participants diagnosed with OCD and 38 healthy controls performed a variation of the Stroop task using colored arrows.

RESULTS

The OCD group presented with larger LRP amplitudes than the control group. This effect was found specifically in the incongruent condition. Furthermore, an interaction effect was found between group and congruency such that the OCD group showed a reduced N2 in the incongruent condition compared to the congruent condition, whereas the control group demonstrated the opposite effect. Results support the hypothesis that OCD is characterized by stronger readiness-for-action and impaired inhibitory mechanisms, particularly when the suppression of a dominant response tendency is required. Our results were supported by source localization analyses for the LRP and N2 components. These findings were specific to OCD and not associated with anxiety and depression symptoms.

CONCLUSIONS

The present results support the notion of stronger habitual behavior and embodiment tendencies in OCD and impaired inhibitory control under conditions of conflict.

Effects of adaptive and non-adaptive three-week executive control training on interference control: Evidence from the N2, CRN, and ERN

The current pilot study investigated if interference control can be improved by a three-week at-home training comprising a flanker and a n-back task in healthy adults, thus exploring the training's suitability for future clinical application, i.e. as a treatment augmentation for psychological disorders. As training gains are assumed to be modulated by the amount of mismatch between task demands and brain resources, an adaptive and a non-adaptive training were contrasted in separate experiments. In the adaptive training, task difficulty was continuously adapted to participants' performance. In the non-adaptive training procedure, task difficulty remained stable on the lowest difficulty level. As deficits in interference control in psychological disorders often predominantly manifest on the electrophysiological level, the impact of the training procedures on medio-frontal negativities (N2, CRN, ERN) was investigated in addition to behavioral measures. The adaptive training led to significant improvements in interference control, as reflected in reduced response times and error rates in incompatible trials. This was accompanied by specific and complementary changes in medio-frontal negativities: After the adaptive training the N2 in incompatible trials was larger and the CRN in incompatible trials was reduced. The non-adaptive training procedure led to generally faster response times but also an increased error rate, indicating a speed-accuracy trade-off. This was accompanied by global changes to medio-frontal negativities irrespective of compatibility, possibly indicating task disengagement. Taken together, the current studies demonstrate that an adaptive training procedure can improve interference control thereby opening up possible clinical applications.

Neuropsychological Research in Obsessive-Compulsive Disorder: Current Status and Future Directions

Neuropsychological functions in obsessive-compulsive disorder (OCD) have been extensively investigated. Despite some common findings across studies indicating deficient test performance across cognitive domains with small to medium effect sizes, results remain inconsistent and heterogeneous. However, multiple past attempts to identify moderators that may account for such variability have been unrewarding. Typical moderators including symptom severity, age at onset, medication status, and comorbid conditions failed to provide sufficient explanatory power. It has then been posited that these inconsistencies may be attributed to the inherent heterogeneous nature of the disorder (i.e., symptom dimensions), or to the natural fluctuation in symptom severity. However, recent meta-analyses suggest that these factors may not account for the persistent unexplained variability. Other potential factors-some of which are unique to neuropsychological testing-received scarce research attention, including definition of cognitive impairments, specificity and selection of test and outcome measures, and their limited ecological validity. Other moderators, particularly motivational aspects, and metacognitive factors (e.g., self-efficacy) were not previously addressed despite their potential association to OCD, and their documented impact on cognitive function. The aim of the present mini-review is to provide an updated succinct overview of the current status of the neuropsychological literature in OCD and expanding upon oft-neglected potential moderators and their putative impact on neuropsychological findings in OCD. Our goal is to highlight important avenues for further research and provide a road map for investigators in order to advance our understanding of cognitive functions in OCD that has been stagnant in the past decade.

Using supervised machine learning on neuropsychological data to distinguish OCD patients with and without sensory phenomena from healthy controls

OBJECTIVES

While theoretical models link obsessive-compulsive disorder (OCD) with executive function deficits, empirical findings from the neuropsychological literature remain mixed. These inconsistencies are likely exacerbated by the challenge of high-dimensional data (i.e., many variables per subject), which is common across neuropsychological paradigms and necessitates analytical advances. More unique to OCD is the heterogeneity of symptom presentations, each of which may relate to distinct neuropsychological features. While researchers have traditionally attempted to account for this heterogeneity using a symptom-based approach, an alternative involves focusing on underlying symptom motivations. Although the most studied symptom motivation involves fear of harmful events, 60-70% of patients also experience sensory phenomena, consisting of uncomfortable sensations or perceptions that drive compulsions. Sensory phenomena have received limited attention in the neuropsychological literature, despite evidence that symptoms motivated by these experiences may relate to distinct cognitive processes.

METHODS

Here, we used a supervised machine learning approach to characterize neuropsychological processes in OCD, accounting for sensory phenomena.

RESULTS

Compared to logistic regression and other algorithms, random forest best differentiated healthy controls (n = 59; balanced accuracy = .70), patients with sensory phenomena (n = 29; balanced accuracy = .59), and patients without sensory phenomena (n = 46; balanced accuracy = .62). Decision-making best distinguished between groups based on sensory phenomena, and among the patient subsample, those without sensory phenomena uniquely displayed greater risk sensitivity compared to healthy controls (d = .07, p = .008).

CONCLUSIONS

Results suggest that different cognitive profiles may characterize patients motivated by distinct drives. The superior performance and generalizability of the newer algorithms highlights the utility of considering multiple analytic approaches when faced with complex data.

PRACTITIONER POINTS

Practitioners should be aware that sensory phenomena are common experiences among patients with OCD. OCD patients with sensory phenomena may be distinguished from those without based on neuropsychological processes.

Control over task conflict in the stroop and affordances tasks: an individual differences study

Task conflict is a type of conflict that emerges when a stimulus triggers two or more competing tasks. In the Stroop task, task conflict occurs between the relevant color-naming task and irrelevant word reading task and can be observed mainly on congruent trials, which only involve task conflict and are devoid of additional conflict types. We hypothesized that task conflict also manifests in the affordances task between the relevant task (e.g., classifying manipulatable objects), and the automatic task afforded by the object (e.g., grasping the object), and is mostly evident on congruent trials. Using an individual differences design we assessed the relationship between control mechanisms operating on Stroop congruent and affordances congruent trials under conditions of high and low cognitive control requirements. We hypothesized that task control is employed in both tasks. One-hundred and twenty-three participants performed an affordances task and two blocks of a Stroop task, each requiring a different level of task control (high vs. low). In a hierarchical regression model, we found a significant and specific correlation between affordances congruent and Stroop congruent conditions only in the high-control block, designed to greatly engage participants' task control, thus linking the task control mechanism in both tasks. These results indicate that task control underlies diverse modalities of response (visuomotor and linguistic), independently of other conflict types. We suggest that the affordances task may serve as a supplementary tool for the assessment of task control in the lab.

The erring brain: Error-related negativity as an endophenotype for OCD-A review and meta-analysis

Obsessive-compulsive disorder (OCD) is a complex and heterogeneous disorder that is associated with high personal and societal costs. Feelings of doubt, worry, and repetitive behavior, key symptoms of OCD, have been linked to hyperactive error signals in the brain. The error-related negativity (ERN) represents a validated marker of error processing in the ERP. Increased ERN amplitudes in OCD have been reported very robustly over the last 20 years. This article integrates results from 38 studies analyzing the ERN in OCD, using a quantitative meta-analysis. Meta-regressions were used to examine potential moderators such as task type, symptom severity, age, and sample size. The meta-analysis reveals a robust increase of ERN in OCD patients compared to healthy participants in response-conflict tasks (SMD -0.55) that is not modulated by symptom severity and age. No increase in ERN in OCD was observed in tasks that do not induce response conflict (SMD -0.10). In addition to the meta-analysis, the current article reviews evidence supporting that increased ERN amplitudes in OCD fulfill central criteria for an endophenotype. Further, the specificity of increased ERN amplitudes for OCD and its suitability as a potential transdiagnostic endophenotype is discussed. Finally, the clinical utility and clinical applications are examined. Overall, the evidence that increased ERN amplitudes represent a promising endophenotype indicating vulnerability for OCD is compelling. Furthermore, alterations in ERN are not limited to OCD and may constitute a transdiagnostic endophenotype. Altered neural error signals might serve as a diagnostic or predictive marker and represent a promising target for interventions.

Evidence for trial-by-trial dynamic adjustment of task control in unmedicated adults with OCD

According to the conflict monitoring theory, executive control requires two separable processes: conflict-monitoring and conflict-resolution. Deficits in executive control have been observed in adults with obsessive-compulsive disorder (OCD). However, it is not yet clear whether these deficits can be attributed to deficits in conflict-monitoring, in conflict-resolution, or in both. We examined this question by administrating the Simon task to 67 unmedicated adults with OCD and 67 matched controls. The interference effect (incongruent minus congruent) was used to measure conflict-resolution. Trial-by-trial dynamic adaptation (i.e., the Gratton effect), which is indicated by smaller interference effect after conflict-laden trials compared to after non-conflict-laden trials, was used to measure conflict-monitoring. A similar interference effect was found in both the OCD and HC groups with no significant between group differences. Following incongruent trials, the interference effect became smaller for the control group as expected, but was completely eliminated for the OCD group. These data add to the accumulating evidence indicating that conflict-resolution is not globally deficient in unmedicated OCD patients and provide direct evidence that conflict-monitoring is heightened in OCD patients. Our results challenge the assumption of cognitive inflexibility in OCD and highlight the importance of studying unmedicated subjects when investigating executive control.

Why check? A meta-analysis of checking in obsessive-compulsive disorder: Threat vs. distrust of senses

Compulsive checking is the most common ritual among individuals with obsessive-compulsive disorder (OCD). Yet, other than uncertainty, the variables prompting checking are not fully understood. Laboratory studies suggest that task conditions - whether threatening (anxiety-relevant) or neutral, and task type - whether requiring perceptual or reasoning decision-making - may be influential. The purpose of our meta-analysis was to compare OCD participants and healthy controls on experimental tasks involving uncertainty in which a behavioral measure of checking was obtained. Four databases were searched. Twenty-two studies met the inclusion criteria, including 43 conditions comparing 663 OCD participants to 614 healthy controls. Due to the dependent structure of the data a robust variance estimation analysis approach was used. Overall effects were similar for neutral and threatening conditions. However, OCD participants responded with greater checking compared to controls on perceptual tasks, but not on reasoning tasks. Results support previous reports suggesting that OCD checking can be observed in neutral conditions, possibly posing as a risk factor for a checking vicious cycle. In addition, our results support OCD models which focus on checking as stemming from interference with automatic processes and distrust of sensory modalities.

Paradoxical response inhibition advantages in adolescent obsessive compulsive disorder result from the interplay of automatic and controlled processes

Response inhibition deficits have often been described in obsessive compulsive disorder (OCD). Yet, research on response inhibition in OCD focusses on “top-down” controlled mechanisms, and it has been neglected that response inhibition performance depends on the interplay of controlled and automatic processes during response selection. Based on pathophysiological considerations we test the counterintuitive hypothesis that OCD patients show superior inhibitory control when automatic mechanisms govern processes involved in response inhibition. We examined a group of adolescent OCD patients (n = 27) and healthy controls (n = 27) using a combined Simon-Go/NoGo task. This task is able to examine conjoint effects of automatic and controlled processes during response inhibition. EEG and source localization analyses were applied to examine the underlying neural mechanisms. OCD patients committed fewer false alarms than healthy controls (HC) in the congruent Simon-NoGo condition, which is dominated by automatic response selection mechanisms. On a neurophysiological (EEG) level, these effects were reflected by intensified correlates of ‘braking’ processes associated with modulation of right inferior prefrontal regions. There is no general response inhibition deficit in adolescent OCD. When considering conjoint effects of automatic and controlled processes during the inhibition of responses paradoxical response inhibition advantages can emerge in OCD. This is likely a result of otherwise pathological fronto-striatal hyperactivity and loss of a situation-specific modulation of response selection mechanisms in OCD.

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Effects of automatic/controlled processes on response inhibition (RI) are studied.

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OCD patients show better performance in automatic vs. controlled RI.

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Underlying neurophysiological (EEG) processes are delineated.

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Activation differences in the rIFG are associated with this effect.

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Effects are discussed in neurobiological frameworks of OCD.

The impact of symptom severity on cognitive function in obsessive-compulsive disorder: A meta-analysis

Research on cognitive functions in obsessive-compulsive disorder (OCD) is notoriously heterogeneous with no moderators identified that account for this variability. OCD severity is the primary potential moderator of interest given the longstanding trait versus state debate. Nevertheless, severity has been previously assessed exclusively as a moderator and was not directly and systematically investigated. To address this gap in the literature, the aim of this study was to conduct a systematic meta-analytic review of correlations between cognitive function and symptom severity in OCD samples. Thirty-eight studies were included, allowing for analysis of 132 effects and meta-regression analyses for potential moderators. Small effects were found for the association between cognitive function and symptom severity on major neuropsychological domains, and some subdomains exhibited medium effects for this association. However, several significant methodological and conceptual problems were identified, including the use of the Yale-Brown Obsessive-Compulsive Scale that assesses severity in the past week and not at time of testing, a tendency to not report non-significant correlations, and problematic ecological validity of neuropsychological tests in OCD. In conclusion, we found a small-to-moderate degree of association between OCD symptom severity and cognitive function, but results should be interpreted cautiously given the limitations identified. We offer recommendations that will facilitate future research into this association and move the field beyond the largely stagnant debate about the state versus trait nature of cognitive functioning in OCD, and across disorders.

The effects of awareness and secondary task demands on Stroop performance in the pre-cued lists paradigm

Prior research has demonstrated that explicit pre-cues informing participants of the proportion congruence of an upcoming list of Stroop trials affect performance in mostly congruent lists but not mostly incongruent lists. This pattern suggests a limited role for expectations in influencing Stroop performance. An alternative explanation, however, is that the effects of pre-cues may be masked by a bleed-over of awareness (of the proportion congruence manipulation) from cued to uncued lists given use of a within-subjects manipulation of cueing in prior research. One aim of the current study was to test this explanation by examining patterns of cueing effects when cueing is manipulated between subjects. A second aim was to examine the effects of a secondary, stimulus detection task on expectation and experience-driven effects in the pre-cued lists paradigm. Countering the bleed-over of awareness account, the prior finding of a selective effect of expectations in mostly congruent lists was again observed in the current experiments, and post-experimental assessments of awareness in the uncued condition were unrelated to Stroop performance. Additionally, it was demonstrated that the secondary task did not disrupt experience-driven control but did disrupt the expectation-driven use of pre-cues especially when participants did not know that secondary task stimuli would appear in advance of a list. These findings advance our understanding of the role of awareness in patterns of Stroop performance, and raise interesting questions about the types of advance knowledge that can be integrated in an expectation-driven fashion to optimize Stroop performance.

Stopping at a red light: Recruitment of inhibitory control by environmental cues

Environmental cues can influence basic perceptual and attentional processes especially in an emotional context. In the current study, we aimed to investigate the effect of a non-emotional common environmental cue-a traffic light-on a higher cognitive operation-inhibition. In two experiments, we administered a novel version of the stop-signal task, in which the go task was to determine the color of a traffic light. In order to investigate the influence of each of the cues on inhibitory processes, separate tracking procedures (one for each cue) were applied simultaneously to the stop-signal delay. In Experiment 1, we found that reaction time in no-stop-signal trials was faster when a green traffic light was present, whereas stop-signal reaction time was longer when a red traffic light was present. In Experiment 2, neutral control cues were used in addition to a red and green light. The results indicate that the differences between red and green stem from an association between the color red and stop processes (rather than from the green-go association). These results strengthen previous findings showing the effect of environmental cues on attentional processes and go beyond them by showing that the effect is not restricted to emotional cues. Most importantly, the current study results suggest that environmental cues can also influence complex cognitive operations such as inhibitory control. These results might have specific implications for our understanding of the processes that underlie specific psychiatric disorders characterized by inhibitory deficit.

Negative Mood and Obsessive-Compulsive Related Clinical Constructs: An Examination of Underlying Factors

Emerging evidence suggests that many of the clinical constructs used to help understand and explain obsessive-compulsive (OC) symptoms, and negative mood, may be causally interrelated. One approach to understanding this interrelatedness is a motivational systems approach. This approach suggests that rather than considering clinical constructs and negative affect as separable entities, they are all features of an integrated threat management system, and as such are highly coordinated and interdependent. The aim of the present study was to examine if clinical constructs related to OC symptoms and negative mood are best treated as separable or, alternatively, if these clinical constructs and negative mood are best seen as indicators of an underlying superordinate variable, as would be predicted by a motivational systems approach. A sample of 370 student participants completed measures of mood and the clinical constructs of inflated responsibility, intolerance of uncertainty, not just right experiences, and checking stop rules. An exploratory factor analysis suggested two plausible factor structures, one where all construct items and negative mood items loaded onto one underlying superordinate variable, and a second structure comprising of five factors, where each item loaded onto a factor representative of what the item was originally intended to measure. A confirmatory factor analysis showed that the five factor model was preferential to the one factor model, suggesting the four constructs and negative mood are best conceptualized as separate variables. Given the predictions of a motivational systems approach were not supported in the current study, other possible explanations for the causal interrelatedness between clinical constructs and negative mood are discussed.

To Do or Not to Do? Task Control Deficit in Obsessive-Compulsive Disorder

Task control is an executive control mechanism that facilitates goal-directed task selection by suppressing irrelevant automatic "stimulus-driven" behaviors. In the current study, we test the hypothesis that less efficient task control in individuals diagnosed with obsessive-compulsive disorder (OCD) is associated with OCD symptoms, and specifically, with the inability to inhibit unwanted behaviors in OCD. Thirty-five healthy controls, 30 participants with OCD, and 26 participants with generalized anxiety disorder (GAD) completed the object-interference (OI) task to measure task control, the stop-signal task to measure response inhibition, and the arrow-flanker task to evaluate executive abilities not contingent upon task control. OCD patients, but not GAD patients or healthy controls, exhibited impaired performance on the OI task. The deficit in task control, but not in response inhibition, correlated with OCD symptom severity. We suggest that reduced task control may be one of the neurocognitive processes that underlie the inability to inhibit unwanted behaviors in OCD.

Executive Dysfunction in Obsessive-Compulsive Disorder and Anterior Cingulate-Based Resting State Functional Connectivity

OBJECTIVE

Executive dysfunction might be an important determinant for response to pharmacotherapy in obsessive-compulsive disorder (OCD), and could be sustained independently of symptom relief. The anterior cingulate cortex (ACC) has been indicated as a potential neural correlate of executive functioning in OCD. The present study examined the brain-executive function relationships in OCD from the ACC-based resting state functional connectivity networks (rs-FCNs), which reflect information processing mechanisms during task performance.

METHODS

For a total of 58 subjects [OCD, n=24; healthy controls (HCs), n=34], four subdomains of executive functioning were measured using the Rey-Osterrieth Complex Figure Test (RCFT), the Stroop Color-Word Test (SCWT), the Wisconsin Card Sorting Test (WCST), and the Trail Making Test part B (TMT-B). To probe for differential patterns of the brain-cognition relationship in OCD compared to HC, the ACC-centered rs-FCN were calculated using five seed regions systemically placed throughout the ACC.

RESULTS

Significant differences between the OCD group and the HCs with respect to the WCST perseverative errors, SCWT interference scores, and TMT-B reaction times (p<0.05) were observed. Moreover, significant interactions between diagnosis×dorsal ACC [S3]-based rs-FCN strength in the right dorsolateral prefrontal cortex for RCFT organization summary scores as well as between diagnosis×perigenual ACC [S7]-based rs-FCN strength in the left frontal eye field for SCWT color-word interference scores were unveiled.

CONCLUSION

These network-based neural foundations for executive dysfunction in OCD could become a potential target of future treatment, which could improve global domains of functioning broader than symptomatic relief.

The Role of Response Inhibition in Medicated and Unmedicated Obsessive-Compulsive Disorder Patients: Evidence from the Stop-Signal Task

BACKGROUND

Numerous studies have investigated response inhibition (RI) in obsessive-compulsive disorder (OCD), with many reporting that OCD patients demonstrate deficits in RI as compared to controls. However, reported effect sizes tend to be modest and results have been inconsistent, with some studies finding intact RI in OCD. To date, no study has examined the effect of medications on RI in OCD patients.

METHODS

We analyzed results from a stop-signal task to probe RI in 65 OCD patients (32 of whom were medicated) and 58 healthy controls (HCs).

RESULTS

There was no statistically significant difference in stop-signal reaction time between the OCD group and the HC group, or between the medicated and unmedicated OCD patients. However, variability was significantly greater in the medicated OCD group compared to the unmedicated group.

CONCLUSIONS

These results indicate that some samples of OCD patients do not have deficits in RI, making it unlikely that deficient RI underlies repetitive behaviors in all OCD patients. Future research is needed to fully elucidate the impact of medication use on stop-signal performance. Implications for future research on the cognitive processes underlying repetitive thoughts and behaviors are discussed.