Discrepant target detection and action monitoring in obsessive-compulsive disorder

Heritability of frontal brain function related to action monitoring

Monitoring the correspondence between the intended and actually executed action, a fundamental mechanism of behavioral regulation, is reflected by error-related negativity (ERN), an ERP component generated by the anterior cingulate cortex. This study examined genetic influences on the ERN and other components related to action monitoring (correct negativity, CRN, and error positivity, Pe). A flanker task was administered to adolescent twins (age 12) including 99 monozygotic (MZ) and 175 dizygotic (DZ) pairs. Genetic analysis showed substantial heritability of all three ERP components (40%-60%) and significant genetic correlations between them. This study provides the first evidence for heritable individual differences in the neural substrates of action monitoring and suggests that ERN, CRN, and Pe can potentially serve as endophenotypes for genetic studies of personality traits and psychopathology associated with abnormal regulation of behavior.

Clinical correlates of word recognition memory in obsessive-compulsive disorder: an event-related potential study

Memory disturbances found in obsessive-compulsive disorder (OCD) may partially be related to dysfunction of cortico-subcortical circuits. However, it is still unknown how OCD symptomatology is related to memory processing. To explore this question, event-related potentials (ERPs) were recorded in a continuous word-recognition paradigm in OCD patients with either severe or moderate scores on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) (group S and group M, n=8 each) and in normal healthy controls (n=16). Typically ERPs to repeated items are characterized by more positive waveforms beginning approximately 250 ms post-stimulus. This "old/new effect" has been shown to be relevant for memory processing. The early old/new effect (ca. 300-500 ms) with a frontal distribution is proposed to be a neural correlate of familiarity-based recognition. The late old/new effect (post-500 ms) is assumed to reflect conscious memory retrieval processes. The OCD group S showed a normal early old/new effect and a reduced late old/new effect compared with group M and the control group, but no difference was found between group M and the control group. Source analyses for the late old/new effect showed statistically reduced cerebral activation in the anterior cingulate for OCD group S in contrast to the control group. Additionally, the early old/new effect in OCD group S was negatively correlated with the Y-BOCS total scores, and the late old/new effect was negatively correlated with obsession sub-scores. The severely, not moderately, ill OCD patients showed an impaired conscious recollection of the word-to-be-remembered, which suggested an impairment of working memory capacity in these patients due to a dysfunction in the frontal and cingulate cortex.

Nucleus Accumbens is Involved in Human Action Monitoring: Evidence from Invasive Electrophysiological Recordings

The Nucleus accumbens (Nacc) has been proposed to act as a limbic-motor interface. Here, using invasive intraoperative recordings in an awake patient suffering from obsessive-compulsive disease (OCD), we demonstrate that its activity is modulated by the quality of performance of the subject in a choice reaction time task designed to tap action monitoring processes. Action monitoring, that is, error detection and correction, is thought to be supported by a system involving the dopaminergic midbrain, the basal ganglia, and the medial prefrontal cortex. In surface electrophysiological recordings, action monitoring is indexed by an error-related negativity (ERN) appearing time-locked to the erroneous responses and emanating from the medial frontal cortex. In preoperative scalp recordings the patient's ERN was found to be significantly increased compared to a large (n = 83) normal sample, suggesting enhanced action monitoring processes. Intraoperatively, error-related modulations were obtained from the Nacc but not from a site 5 mm above. Importantly, cross-correlation analysis showed that error-related activity in the Nacc preceded surface activity by 40 ms. We propose that the Nacc is involved in action monitoring, possibly by using error signals from the dopaminergic midbrain to adjust the relative impact of limbic and prefrontal inputs on frontal control systems in order to optimize goal-directed behavior.

Genetic and environmental influences on obsessive-compulsive disorder

It is important to understand how genetic and environmental factors interact in the development of obsessive-compulsive disorder (OCD) in order to provide a cohesive model of the underlying pathogenic mechanisms. In this article, we provide an overview of the current knowledge of possible genetic and environmental contributions to the development of OCD. We consider the significant challenges for identifying risk factors for OCD as well as promising avenues for overcoming these obstacles in future research. In particular, we discuss the value of focusing on certain phenotypes, applying a dimensional approach, and investigating possible endophenotypes. We also describe innovative study designs that may be used in future research to explore the interaction between genetic vulnerability and environmental risk factors for OCD.

Overactive performance monitoring in obsessive-compulsive disorder: ERP evidence from correct and erroneous reactions

Obsessive-compulsive disorder (OCD) has repeatedly been associated with hyperactivity in fronto-striatal brain regions and regions related to performance monitoring. The aim of the current study was to further investigate electrophysiological correlates of performance monitoring. Specifically, we intended to replicate previous results revealing enhanced error-related negativity (ERN) amplitudes in OCD patients. Furthermore, we examined whether OCD patients also showed alterations regarding the correct-related negativity (CRN), the error positivity (Pe) and behavioural correlates of performance monitoring. Event-related brain potentials (ERPs) were recorded from a group of 20 OCD patients and 20 healthy control participants during a modified flanker task. Force sensitive response buttons were utilized to separate correct trials from incorrect trials with full and partial response activation. Both groups displayed substantial ERN and Pe amplitudes for full and partial errors. On error trials OCD patients showed enhanced ERN amplitudes, but group differences were not significant for the Pe and for behavioural adjustment. Further, the OCD group also exhibited enhanced CRN amplitudes and a correlation of frontal CRN amplitudes with symptom severity. These data provide further support for the view that performance monitoring is overactive in OCD. Further, since the amplitude enhancement is not specific to error processing, but is also observed for correct reactions, a response monitoring or evaluation process that contributes to both ERP components might be overactive in OCD. This is in line with fMRI results that revealed higher error- and conflict-related activity in the medial frontal cortex in OCD patients.

Executive control in obsessive-compulsive disorder: event-related potentials in a Go/Nogo task

Obsessive-compulsive disorder (OCD) has been related to a hyperactive cortico-striatal-pallidal-thalamic circuitry resulting clinically in an impaired inhibition of repetitive thoughts and behaviors. We examined thirteen patients with OCD and thirteen age-, sex-, and education matched healthy controls using event-related potentials (ERPs). Participants performed a hybrid flanker-Go/Nogo task while multichannel EEG was recorded. Our study focused on two ERP components: the Nogo-N2 and the Nogo-P3, which have been discussed in the context of response inhibition and response conflict. Artifact-free EEG-segments were used to compute ERPs on correct Go trials (button press) and correct Nogo trials (no button press), separately. Patients with OCD showed enhanced (more negative) Nogo-N2 amplitudes than controls, and a significant difference in amplitudes between Nogo-N2 and Go-N2 trials (more negative for Nogo trials) at central midline electrode positions. However, groups did not differ with regard to the Nogo-P3 and Go-P3. The present study replicates and extends previous findings of altered executive control processes in OCD patients.

Adaptive control deficits in attention-deficit/hyperactivity disorder (ADHD): the role of error processing

Cognitive performance of children with attention-deficit hyperactivity disorder (ADHD) is characterized by large moment-to-moment fluctuations in cognitive control reflected by a highly inconsistent and inaccurate response style. It has been suggested that abnormal error processing underlies this failure to implement adequate control. We investigated the error-related negativity (ERN), a negative deflection in the event-related potential (ERP) time-locked to erroneous responses in 16 rigorously screened ADHD boys aged 8-12 years and 16 age-matched normal control boys during a modified Eriksen flanker paradigm with two levels of time pressure. Children with ADHD responded as fast and regularly as controls, but committed significantly more errors, particularly when facing time pressure and response conflict. ADHD children produced shorter runs of correct responses than controls. In addition, with high time pressure, error runs were prolonged relative to control children, suggesting an increase in both frequency and magnitude of temporary lapses of control. ERP amplitude differences between correct and incorrect responses were diminished in ADHD children, whereas post-error slowing remained unaffected. This pattern of results indicates that a specific deficit in monitoring ongoing behaviour, rather than insufficient strategic adjustments, gave rise to performance limitations in ADHD. Findings are discussed in terms of anterior cingulate cortex (ACC) dysfunction, leading to a failure to predict the likelihood that an error occurs in a given context.

Annotation: what electrical brain activity tells us about brain function that other techniques cannot tell us - a child psychiatric perspective

BACKGROUND

Monitoring brain processes in real time requires genuine subsecond resolution to follow the typical timing and frequency of neural events. Non-invasive recordings of electric (EEG/ERP) and magnetic (MEG) fields provide this time resolution. They directly measure neural activations associated with a wide variety of brain states and processes, even during sleep or in infants. Mapping and source estimation can localise these time-varying activation patterns inside the brain.

METHODS

Recent EEG/ERP research on brain functions in the domains of attention and executive functioning, perception, memory, language, emotion and motor processing in ADHD, autism, childhood-onset schizophrenia, Tourette syndrome, specific language disorder and developmental dyslexia, anxiety, obsessive-compulsive disorder, and depression is reviewed.

RESULTS

Over the past two decades, electrophysiology has substantially contributed to the understanding of brain functions during normal development, and psychiatric conditions of children and adolescents. Its time resolution has been important to measure covert processes, and to distinguish cause and effect.

CONCLUSIONS

In the future, EEG/ERP parameters will increasingly characterise the interplay of neural states and information processing. They are particularly promising tools for multilevel investigations of etiological pathways and potential predictors of clinical treatment response.

Neural systems for error monitoring: recent findings and theoretical perspectives

Complex behavior requires a flexible system that maintains task performance in the context of specific goals, evaluating behavioral progress, adjusting behavior as needed, and adapting to changing contingencies. Generically referred to as performance monitoring, a key component concerns the identification and correction of differences between an intended and an executed response (i.e., an error). Brain mapping experiments have now identified the temporal and spatial components of a putative error-processing system in the large-scale networks of the human brain. Most of this work has focused on the medial frontal cortex and an associated electrophysiological component known as the error-related negativity (or error negativity). Although the precise role, or roles, of this region still remain unknown, investigations of error processing have identified a cluster of modules in the medial frontal cortex involved in monitoring/maintaining ongoing behavior and motivating task sets. Other regions include bilateral anterior insula/inferior operculum and lateral prefrontal cortex. Recent work has begun to uncover how individual differences might affect the modules recruited for a task, in addition to the identification of associations between pathological states and aberrant error signals, leading to insights about possible mechanisms of neuropsychiatric illness.

Attention and cognition in patients with obsessive-compulsive disorder

Although a dysfunctional prefrontal-striatal system is presupposed in obsessive-compulsive disorder (OCD), this is not sustained by neuropsychological studies. The aim of this study was twofold: (i) to investigate the cognitive deficits in patients with OCD compared to matched healthy controls; and (ii) to relate cognitive performance to clinical characteristics in patients with OCD. In this study, 39 patients with primary OCD according to Diagnostic and Statistical Manual, fourth edition criteria were compared to 26 healthy control subjects on a battery measuring verbal memory and executive functioning. Patients with OCD showed slowed learning on the verbal memory task and made more errors on the Wisconsin Card Sorting Test. Errors were failures to maintain set, which were related to severity of OCD symptomatology. The results show that patients with OCD have cognitive deficits. The authors hypothesize that these deficits may be interpreted by attentional deficits caused by a dysfunctional anterior cingulate cortex.

Action monitoring and perfectionism in anorexia nervosa

To study action monitoring in anorexia nervosa, behavioral and EEG measures were obtained in underweight anorexia nervosa patients (n=17) and matched healthy controls (n=19) while performing a speeded choice-reaction task. Our main measures of interest were questionnaire outcomes, reaction times, error rates, and the error-related negativity ERP component. Questionnaire and behavioral results indicated increased perfectionism in patients with anorexia nervosa. In line with their perfectionism and controlled response style patients made significantly less errors than controls. However, when controlling for this difference in error rates, the EEG results demonstrated a reduced error-related negativity in the patient group. These seemingly contradictory outcomes of improved performance and reduced error monitoring are discussed in relation with indications of anterior cingulate cortex hypoactivity in anorexia nervosa patients.

Error-processing deficits in patients with cocaine dependence

Cocaine abuse and addiction can be characterized by a persisting use of cocaine in the face of adverse consequences. In the present study we focus on one specific element of adverse consequences: the making of errors. The aim of this study was to determine whether cocaine-dependent persons have error-processing deficits as measured using error-related negativity (ERN) and error positivity (Pe). Event-related potentials (ERPs) during an Eriksen flanker task were recorded from cocaine-dependent patients and a control group. Cocaine-addicted patients showed reduced ERN and Pe components as compared to a control group. On the behavioral level, patients showed reduced post-error accuracy improvement. The present findings reveal that cocaine addiction is associated with reduced error processing and impaired behavioral correction of errors after an error is made. These deficits may be associated with a compromised dopamine system. It is argued that these cognitive deficits may contribute to the maintenance of the cocaine addiction.

Increased error-related negativity (ERN) in childhood anxiety disorders: ERP and source localization

BACKGROUND

In this study we used event-related potentials (ERPs) and source localization analyses to track the time course of neural activity underlying response monitoring in children diagnosed with an anxiety disorder compared to age-matched low-risk normal controls.

METHODS

High-density ERPs were examined following errors on a flanker task from 12 children between 8 and 14 years old diagnosed with an anxiety disorder (ANX) and 13 age-matched low-risk normal controls (LRNC).

RESULTS

Children diagnosed with an anxiety disorder had increased error-related negativity (ERN) amplitude. The neural generators of the ERN in the ANX group were estimated to be localized in the anterior cingulate cortex (ACC). There were no significant group differences in P(E) amplitude.

CONCLUSIONS

These data provide evidence for increased ERN amplitude localized to the ACC in children diagnosed with an anxiety disorder, suggesting altered maturational patterns of the ACC circuitry early in the course of this illness.

Error-related electrocortical responses are enhanced in children with obsessive-compulsive behaviors

The error-related negativity (ERN or Ne) and positivity (Pe) are event-related potential components elicited during simple discrimination tasks after an error response. The ERN and Pe have a fronto-central scalp distribution and may be an indirect measure of anterior cingulate (AC) activity as it relates to performance monitoring. Brain imaging studies suggest that obsessive-compulsive disorder (OCD) is associated with exaggerated activity of the AC while electrophysiological studies have found an association between OCD and pronounced ERNs in adults. The present study explored the relation between obsessive-compulsive behaviors, the ERN, and the Pe in a sample of nonclinical 10-year-old children. It was found that more parent-reported obsessive-compulsive behaviors were associated with larger ERN and Pe components in the children. Results suggest unique contributions of the ERN and Pe in predicting obsessive-compulsive behaviors.

Response monitoring, the error-related negativity, and differences in social behavior in autism

Children with autism not only display social impairments but also significant individual differences in social development. Understanding the source of these differences, as well as the nature of social impairments, is important for improved diagnosis and treatments for these children. Current theory and research suggests that individual differences in response monitoring, a specific function of the anterior cingulate cortex (ACC), may contribute to social-emotional and social-cognitive impairments and individual differences in autism. To examine this hypothesis, we used a modified flanker task to assess an ERP index of response monitoring, the error-related negativity (ERN), in a sample of higher function children with autism (HFA) and an IQ-matched control sample. The results revealed a significant Diagnostic group by Verbal IQ interaction on ERN amplitude indicating that the most verbally capable HFA children displayed significantly larger ERN amplitudes than did the control children. Within the HFA sample, greater ERN amplitude was also related to parent reports of fewer symptoms of social interaction impairments, fewer internalizing problems, but more externalizing problems, although these associations were reduced to nonsignificance when medication status was controlled. The latter results complement previous observations from imaging studies of a significant association between ACC activity and social symptoms and impairments in autism. The implications of these results for future research on brain-behavior relations, as well as treatment related research with children with autism are discussed.

Electrophysiological correlates of error processing in borderline personality disorder

The electrophysiological correlates of error processing were investigated in patients with borderline personality disorder (BPD) using event-related potentials (ERP). Twelve patients with BPD and 12 healthy controls were additionally rated with the Barratt impulsiveness scale (BIS-10). Participants performed a Go/Nogo task while a 64 channel EEG was recorded. Three ERP components were of special interest: error-related negativity (ERN)/error negativity (Ne), early error positivity (early Pe) reflecting automatic error processing, and the late Pe component which is thought to mirror the awareness of erroneous responses. We found smaller amplitudes of the ERN/Ne in patients with BPD compared to controls. Moreover, significant correlations with the BIS-10 non-planning sub-score could be demonstrated for both the entire group and the patient group. No between-group differences were observed for the early and late Pe components. ERP measures appear to be a suitable tool to study clinical time courses in BPD.

Medial frontal cortex activity and loss-related responses to errors

Making an error elicits activity from brain regions that monitor performance, especially the medial frontal cortex (MFC). However, uncertainty exists about whether the posterior or anterior/rostral MFC processes errors and to what degree affective responses to errors are mediated in the MFC, specifically the rostral anterior cingulate cortex (rACC). To test the hypothesis that rACC mediates a type of affective response, we conceptualized affect in response to an error as a reaction to loss and amplified this response with a monetary penalty. While subjects performed a cognitive interference task during functional magnetic resonance imaging, hemodynamic activity in the rACC was significantly greater when subjects lost money as a result of an error compared with errors that did not lead to monetary loss. A significant interaction between the incentive conditions and error events demonstrated that the effect was not merely attributable to working harder to win (or not lose) money, although an effect of motivation was noted in the mid-MFC. Activation foci also occurred in similar regions of the posterior MFC for error and interference processing, which were not modulated by the incentive conditions. However, at the level of the individual subject, substantial functional variability occurred along the MFC during error processing, including foci in the rostral/anterior extent of the MFC not appearing in the group analysis. The findings support the hypothesis that the rostral extent of the MFC (rACC) processes loss-related responses to errors, and individual differences may account for some of the reported variation of error-related foci in the MFC.

Error detection mechanisms of the brain: background and prospects

Historical background of error detection (ED) studies is restored here from the first suggestion of such a mechanism published (Rabbit, 1966) and the first related anatomo-physiological correlates observed [Bechtereva, N.P., Gretchin, V.B., 1968. Physiological foundations of mental activity. Int. Rev. Neurobiol., vol. 11. Academic Press, N.Y., pp. 239-246; Bechtereva, N.P., 1971. Neurophysiological Aspects of Human Mental Activity. Meditzina, Moskow. 120 pp., (in Russian); Bechtereva, N.P., 1974. Neurophysiological Aspects of Human Mental Activity, second edition, revied and complete Meditzina, Moskow. 151 pp., (in Russian)]. Data from evoked potentials together with new opportunities offered by the technological revolution of the 1980s-1990s provided a large body of knowledge on the ED. The overwhelming majority of the papers stress the spatial relation of ED to Anterior Cingulate Cortex. ED was revealed in a number of other zones to whose role should be specially discussed. The other point of interest is the late appearance of ED after the brain signs of correction which seems particularly important considering the supposed functional role of ED. Data of direct observations of ECoG dynamics in left and right human ACC on correct and erroneous test performance are presented. Research on ED resulted in the development of new ways in treatment of the obsessive-compulsive syndrome. Further psychophysiological research into the ED phenomena is considered as one of the priorities of fundamental and applied investigations for the elucidation of human brain functions. Opinion that ED plays an extremely important role in mechanisms of cognition and creativity is further argumented. Investigations in the field can contribute a lot to clinical neurophysiology as well.

On the ERN and the significance of errors

The error-related negativity (ERN) is an event-related brain potential observed when subjects commit errors. To examine whether the ERN is sensitive to the value of errors, the motivational significance of errors was manipulated in two experiments. In Experiment 1, low and high monetary value errors were compared to evaluate the effect of trial value on the ERN. In Experiment 2, subjects performed a flanker task both while their performance was being evaluated and during a control condition. Consistent with the notion that the error-detection system is sensitive to the significance of errors, the ERN was significantly larger on high-value trials in Experiment 1 and during evaluation in Experiment 2. There were no corresponding effects on the correct response negativity, and no behavioral differences between conditions were evident in either experiment. These results are discussed in terms of the functional role of the ERN in response monitoring.

Cardiac concomitants of performance monitoring: context dependence and individual differences

Feedback processing is an important aspect of cognitive control and decision-making. Several studies have shown that heart rate slows following feedback that indicates incorrect performance or loss of money. The current study was the first to investigate (1) whether this slowing reflects an evaluation of the valence of the outcome or a system that indicates that the feedback contains informative value, (2) whether the slowing is determined by the value of the outcome relative to the range of possible outcomes, and (3) whether highly anxious individuals have a hypersensitive feedback monitoring system. The results showed that heart rate only slows when the feedback is performance based. The information provided by negative feedback is processed in a context-sensitive manner, suggesting that heart rate slowing following feedback reflects a signal associated with informative value for subsequent performance adjustment. Highly anxious individuals showed larger heart rate slowing in response to feedback indicating high stakes, but they failed to respond to feedback in a context-sensitive manner. These results were interpreted to suggest that anxious individuals are generally more sensitive to performance outcomes. Heart rate changes following informative feedback proved to be a sensitive index of component processes associated with performance monitoring.

The effects of fear on performance monitoring and attentional allocation

Evidence from event-related potential (ERP) studies indicates abnormal error processing and attentional allocation in "trait"-anxious individuals. However, few studies have been conducted that evaluate relevant ERP components during the induction of an anxious state (i.e., fear). In the present study, ERPs were measured in 16 undergraduates during control and fear induction conditions to examine the effects of fear on error processing and attentional allocation. Despite comparable performance in both experimental conditions, the ERP data indicated reductions in attentional allocation and error salience during fear induction. Fear did not appear to directly alter early error processing, as indicated by the error-related negativity, however. The implication of these results for understanding how trait and state anxiety may affect error processing and attentional allocation are discussed.

Performance monitoring in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is associated with hyperactivity of brain structures involved in performance monitoring. It has been proposed that this pathophysiology results in the generation of inappropriate or excessive internal error signals, giving rise to the characteristic symptoms of OCD. We measured an electrophysiological correlate of performance monitoring, error-related negativity (ERN), to study whether OCD patients exhibit enhanced brain activity associated with errors and negative performance feedback. We found that OCD patients (n=16) and healthy control participants (n=16) did not differ in the amplitude of the ERN associated with errors and negative feedback in a probabilistic learning task. The discrepancy between these results and the results from previous studies is discussed.

Dysfunctional action monitoring hyperactivates frontal-striatal circuits in obsessive-compulsive disorder: an event-related fMRI study

Converging evidence suggests that hyperactivity in frontal-striatal circuits and in action-monitoring processes characterizes obsessive-compulsive disorder (OCD). It remains unclear, however, just how these abnormalities in brain function translate into the cognitive, affective, and behavioral manifestations of OCD. One possibility is that exaggerated or false error signals generated by the anterior cingulate (ACC) underlie compulsive behaviors by triggering the feeling that things are "not just right" even when no actual error has been made. Since recurrent compulsive behavior typically follows correct completion of a behavioral task (e.g., hand washing), ACC hyperactivity should be observed during correctly completed, high-conflict trials as well as during error trials. Frontal-striatal regions would also be expected to be activated during both trial types, as these regions are robustly associated with OCD across multiple neuroimaging paradigms. To test this hypothesis, 14 OCD patients and 14 matched controls completed a speeded reaction time task during functional magnetic resonance imaging (fMRI). Only correctly rejected, high-conflict trials produced excessive activation in both action monitoring (rostral and caudal ACC, LPFC) and frontal striatal regions (lateral orbitofrontal cortex (OFC), caudate, and thalamus) among OCD patients when compared to healthy controls. Portions of the posterior cingulate were also hyperactive among OCD patients. These results suggest that correctly rejected, high-conflict trials that require response inhibition may provide a better model than error trials of compulsive behaviors in OCD.

Error-related hyperactivity of the anterior cingulate cortex in obsessive-compulsive disorder

BACKGROUND

Hyperactivity of the anterior cingulate cortex (ACC) in patients with obsessive-compulsive disorder (OCD) has been shown to increase with symptom provocation and to normalize with treatment-induced symptom reduction. Although the functional significance of anterior cingulate involvement in OCD remains unknown, electrophysiological evidence has linked this region to error-processing abnormalities in patients with OCD. In this functional magnetic resonance imaging (fMRI) study, we sought to further localize error-processing differences within the ACC of OCD patients compared with healthy subjects.

METHODS

Event-related fMRI data were collected for eight OCD patients and seven healthy subjects during the performance of a simple cognitive task designed to elicit errors but not OCD symptoms.

RESULTS

Both OCD patients and healthy subjects demonstrated dorsal ACC activation during error commission. The OCD patients exhibited significantly greater error-related activation of the rostral ACC than comparison subjects. Activity in this region was positively correlated with symptom severity in the patients.

CONCLUSIONS

Error-processing abnormalities within the rostral anterior cingulate occur in the absence of symptom expression in patients with OCD.

Error-Related Brain Activity in Patients with Obsessive- Compulsive Disorder and in Healthy Controls

Abstract: Obsessive-compulsive disorder (OCD) has been related to a hyperactive frontal-striatal-thalamic circuit and associated with altered mechanisms of action and error monitoring. In the present study, we examined whether these results only hold for errors in choice reaction time experiments and Stroop tasks or extend to errors of commission in a Go/NoGo task, as well. We investigated the electrophysiological correlates of error monitoring in 11 patients with OCD and 11 age-, sex-, and education-matched healthy controls using event-related potentials (ERPs). Participants performed a Go/NoGo task while a 64-channel EEG was recorded. Our study focused on three ERP components: the error-related negativity (ERN)/error negativity (Ne), the “early” error positivity (“early” Pe) reflecting automatic error processing, and the “late” error positivity (“late” Pe), which is thought to mirror the awareness of erroneous responses. Artifact-free EEG-segments were used to compute ERPs on correct Go trials and incorrect NoGo trials (i.e., errors of commission), separately. Patients with OCD showed enhanced (more negative) ERN/Ne amplitudes compared to control subjects. Groups did not differ with regard to the early Pe component and the late Pe component. Our results support the view that compulsivity in OCD patients is related to hyper-functioning error monitoring processes.

Error-related psychophysiology and negative affect

The error-related negativity (ERN/Ne) and error positivity (Pe) have been associated with error detection and response monitoring. More recently, heart rate (HR) and skin conductance (SC) have also been shown to be sensitive to the internal detection of errors. An enhanced ERN has consistently been observed in anxious subjects and there is some suggestion that the ERN is related to general negative affective experience (NA). The ERN has been source localized to the anterior cingulate cortex-a structure implicated in the regulation of affective, response selection, and autonomic resources. Thus, the findings that autonomic measures and affective distress are related to response monitoring are consistent with anterior cingulate cortex function. In the present experiment, we sought to evaluate more comprehensively the relationship between self-reported negative affect and error-related physiology in a between-groups design. Results indicate that high NA was associated with significantly greater ERN and error-related SCR, and smaller Pe. These results are discussed in terms of anterior cingulate cortex function, psychopathology, and response monitoring.

The error-related negativity as a state and trait measure: Motivation, personality, and ERPs in response to errors

This study examines changes in the error-related negativity (ERN/Ne) related to motivational incentives and personality traits. ERPs were gathered while adults completed a four-choice letter task during four motivational conditions. Monetary incentives for finger and hand accuracy were altered across motivation conditions to either be equal or favor one type of accuracy over the other in a 3:1 ratio. Larger ERN/Ne amplitudes were predicted with increased incentives, with personality moderating this effect. Results were as expected: Individuals higher on conscientiousness displayed smaller motivation-related changes in the ERN/Ne. Similarly, those low on neuroticism had smaller effects, with the effect of Conscientiousness absent after accounting for Neuroticism. These results emphasize an emotional/evaluative function for the ERN/Ne, and suggest that the ability to selectively invest in error monitoring is moderated by underlying personality.

To err is autonomic: Error-related brain potentials, ANS activity, and post-error compensatory behavior

A two-component event-related brain potential consisting of an error-related negativity (ERN/Ne) and positivity (Pe) has been associated with response monitoring and error detection. Both the ERN and Pe have been source-localized to the anterior cingulate cortex (ACC)--a frontal structure implicated in both cognitive and affective processing, as well as autonomic nervous system (ANS) modulation. The current study sought to examine the relationships among the ERN, the Pe, two autonomic measures, and behavior. Electroencephalogram (EEG), heart rate (HR), and skin conductance (SC) were recorded while subjects performed a two-choice reaction-time task. In addition to the characteristic ERN-Pe complex, errors were associated with larger SCRs and greater HR deceleration. The ERN correlated with the number of errors, but was unrelated to ANS activity and compensatory behavior. Pe, on the other hand, was correlated significantly with SCR, and both SCR and Pe were significantly correlated with post-error slowing.

Reduced response-inhibition in obsessive-compulsive disorder measured with topographic evoked potential mapping

Recent neuroimaging studies have suggested that a hyperactivity of the frontal-striate neuronal circuits, including the orbitofrontal cortex and the basal ganglia, mediates the symptomatology of obsessive-compulsive disorder (OCD). However, there is also some evidence that the superior frontal cortex is less activated in OCD, and this local hypoactivity has been shown to be negatively associated with the symptomatology. As the superior frontal cortex is believed to be involved in inhibitory control, this study investigated the brain electrical activity during response inhibition in OCD. Twelve patients with OCD and 12 healthy controls performed a cued Go-NoGo task (continuous performance test), while event-related potentials were registered with 21 electrodes. Patients reacted significantly faster than controls, but did not differ from controls regarding the error rate. As a main result, we found a reduced frontal activity during the NoGo condition in OCD, which was condensed in a reduced anteriorisation of the brain electrical field. We suggest that this inhibitory deficit in OCD has a major contribution to the pathophysiology of OCD, which is underscored by the fact that the anteriorisation during the NoGo condition (NGA) was negatively correlated with the symptomatology as measured by the Yale-Brown Obsessive-Compulsive Scale.

Anxiety and error-related brain activity

Error-related negativity (ERN/Ne) is a component of the event-related brain potential (ERP) associated with monitoring action and detecting errors. It is a sharp negative deflection that generally occurs from 50 to 150 ms following response execution and has been associated with anterior cingulate cortex (ACC) activity. An enhanced ERN has been observed in patients with obsessive-compulsive disorder (OCD)--reflecting abnormal ACC activity hypothesized as part of the pathophysiology of OCD. We recently reported that the ERN is also enhanced in a group of college students with OC characteristics. The present study extended these findings by measuring the ERN in college undergraduates who scored high on either the Penn State Worry Questionnaire (PSWQ) or a combined version of the Snake (SNAQ) and Spider (SPQ) Questionnaires. Results indicate that, like OC subjects, subjects who score high on a measure of general anxiety and worry have enhanced error-related brain activity relative to both phobic and non-anxious control subjects. The enhanced ERN was found to generalize beyond OCD within the anxiety spectrum disorders but also shows some specificity within these disorders.