Dissociation between conflict detection and error monitoring in the human anterior cingulate cortex

The neural mechanism of encountering misjudgment by the justice system

Although misjudgment is an issue of primary concern to the justice system and public safety, the response to misjudgment by the human brain remains unclear. We used fMRI to record neural activity in participants that encountered four possible judgments by the justice system with two basic components: whether the judgment was right or wrong [accuracy: right vs. wrong (misjudgment)] and whether the judgment was positive or negative [valence: positive vs. negative]. As hypothesized, the rostral ACC specifically processes the accuracy of judgment, being more active for misjudgment than for right judgment, while the striatum was uniquely responsible for the valence of judgment, being recruited to a larger extent by positive judgment compared to negative judgment. Furthermore, the activity in the rACC for positive misjudgments was positively correlated with that for negative misjudgments, which confirmed the misjudgment-specificity of the rACC. These results demonstrate that the brain can distinguish a misjudgment from a right judgment and regard a misjudgment as an emotionally arousing stimulus, independent of whether it is positive or negative, while positive judgment is considered as hedonic information, regardless of whether it is right or wrong. Our study is the first to reveal the neural mechanism that underlies judgment processing. This mechanism may constitute the basis of future studies to develop a novel marker for the detection of lies.

Effects of Low Frequency Prefrontal Repetitive Transcranial Magnetic Stimulation on the N2 Amplitude in a GoNogo Task

During the last decade, repetitive transcranial magnetic stimulation (rTMS) of the prefrontal cortex has become established as a treatment for various mental diseases. The rational of prefrontal stimulation has been adapted from the mode of action known from rTMS using motor-evoked potentials though little is known about the precise effect of rTMS at prefrontal sites. The objective of the current study is to investigate the inhibitory effect of prefrontal 1 Hz rTMS by stimulating the generators of event-related potentials (ERP) which are located in the prefrontal cortex. Thus, 1 Hz rTMS was applied offline over the left dorsolateral prefrontal cortex (DLPFC) and the medial prefrontal cortex (MPFC) in 18 healthy subjects who subsequently underwent a GoNogo task. Both active conditions were compared to sham rTMS within a randomized and counterbalanced cross-over design in one day. ERPs were recorded during task performance and the N2 and the P3 were analysed. After 1 Hz rTMS of the left DLPFC (but not of the MPFC), an inhibitory effect on the N2 amplitude was observed, which was related to inhibitory control. In contrast, after 1 Hz rTMS of the MPFC (but not at the left DLPFC) a trend towards an increased P3 amplitude was found. There was no significant modulation of latencies and behavioural data. The results argue in favour of an inhibitory effect of 1 Hz rTMS on N2 amplitudes in a GoNogo task. Our findings suggest that rTMS may mildly modulate prefrontally generated ERP immediately after stimulation, even where behavioural effects are not measurable. Thus, combined rTMS-ERP approaches need to be further established in order to serve as paradigms in experimental neuroscience and clinical research.

To conform or not to conform: spontaneous conformity diminishes the sensitivity to monetary outcomes

When people have different opinions in a group, they often adjust their own attitudes and behaviors to match the group opinion, known as social conformity. The affiliation account of normative conformity states that people conform to norms in order to ‘fit in’, whereas the accuracy account of informative conformity posits that the motive to learn from others produces herding. Here, we test another possibility that following the crowd reduces the experienced negative emotion when the group decision turns out to be a bad one. Using event related potential (ERP) combined with a novel group gambling task, we found that participants were more likely to choose the option that was predominately chosen by other players in previous trials, although there was little explicit normative pressure at the decision stage and group choices were not informative. When individuals' choices were different from others, the feedback related negativity (FRN), an ERP component sensitive to losses and errors, was enhanced, suggesting that being independent is aversive. At the outcome stage, the losses minus wins FRN effect was significantly reduced following conformity choices than following independent choices. Analyses of the P300 revealed similar patterns both in the response and outcome period. Our study suggests that social conformity serves as an emotional buffer that protects individuals from experiencing strong negative emotion when the outcomes are bad.

Confirmatory factor analysis of the Behavior Rating Inventory of Executive Function-Adult version in healthy adults and application to attention-deficit/hyperactivity disorder

The Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A) is a questionnaire measure designed to assess executive functioning in everyday life. Analysis of data from the BRIEF-A standardization sample yielded a two-factor solution (labeled Behavioral Regulation and Metacognition). The present investigation employed confirmatory factor analysis (CFA) to evaluate four alternative models of the factor structure of the BRIEF-A self-report form in a sample of 524 healthy young adults. Results indicated that a three-factor model best fits the data: a Metacognition factor, a Behavioral Regulation factor consisting of the Inhibit and Self-Monitor scales, and an Emotional Regulation factor composed of the Emotional Control and Shift scales. The three factors contributed 14%, 19%, and 24% of unique variance to the model, respectively, and a second-order general factor accounted for 41% of variance overall. This three-factor solution is consistent with recent CFAs of the Parent report form of the BRIEF. Furthermore, although the Behavioral Regulation factor score in the two-factor model did not differ between adults with attention-deficit/hyperactivity disorder and a matched healthy comparison group, greater impairment on the Behavioral Regulation factor but not the Emotional Regulation factor was found using the three-factor model. Together, these findings support the multidimensional nature of executive function and the clinical relevance of a three-factor model of the BRIEF-A.

Altered cerebral response during cognitive control: a potential indicator of genetic liability for schizophrenia

Aberrant activity in brain regions underlying various aspects of executive cognition has been reported in patients with schizophrenia and in their healthy relatives, suggesting an association with genetic liability. The aim of this study was to investigate brain responses to selective aspects of cognitive control in unaffected siblings who are at increased genetic risk of schizophrenia. Altogether, 65 non-affected siblings, 70 patients with schizophrenia spectrum disorders, and 235 normal controls participated in this study. Blood-oxygen-level-dependent functional magnetic resonance imaging was conducted while participants performed a cognitive control task ('flanker task') to identify brain activity and connectivity associated with response inhibition and conflict monitoring, and suppression. Behaviorally, similar to patients with schizophrenia, siblings were less accurate when inhibiting prepotent responses relative to normal controls. During response inhibition, again similar to patients with schizophrenia, siblings showed decreased activity in the anterior cingulate (ACC), along with increased functional coupling with the dorsolateral prefrontal cortex (PFC) when compared to normal controls. Our findings show altered ACC activity and PFC connectivity in unaffected siblings and patients with schizophrenia during response inhibition. These results suggest that such changes in the neural activity underlying aspects of cognitive control may represent a potential intermediate phenotype for the investigation of the genetic basis of schizophrenia.

Is consciousness necessary for conflict detection and conflict resolution?

Is conflict control dependent on consciousness? To answer this question, we used high temporal resolution event-related potentials (ERPs) to separate conflict detection from conflict resolution in a masked prime Stroop task. Although behavioral interference effect was present in both the masked and unmasked conditions, the electrophysiological findings revealed more complex patterns. ERP analyses showed that N450 was greater for incongruent trials than for congruent trials and that it was located in the ACC and nearby motor cortex, regardless of whether the primes were masked or unmasked; however, the effects were smaller for the masked than unmasked condition. These results suggest that consciousness of conflict information may not be necessary for detecting conflict, but that it may modulate conflict detection. The analysis of slow potential (SP) amplitude showed that it distinguished incongruent trials from congruent trials, and that this modulation effects was reduced to a greater extent for the masked condition than for the unmasked condition. Moreover, the prefrontal-parietal control network was activated under the unmasked but not under the masked condition. These results suggest that the consciousness of conflict information may be a necessary boundary condition for the subsequent initiation of control operations in the more extended PFC-parietal control network. However, considering that the conflict interference effect was significantly reduced in the masked condition, it may be that, with larger unconscious conflict effects, more extensive cognitive control networks would have been activated. These findings have important implications for theories on the relationship between consciousness and cognitive control.

Neurons in the cingulate motor area signal context-based and outcome-based volitional selection of action

Volitional selection of action is subject to continuous adjustment under the influence of information obtained by monitoring behavioral consequences and by exploiting behavioral context based on prior knowledge about the environment. The rostral cingulate motor area (CMAr) is thought to be responsible for adjusting behavior by monitoring its consequences. To investigate whether the CMAr also plays a role in exploitation of behavioral context in action selection, we recorded neuronal activities from the CMAr while monkeys performed a reward-based motor selection task that required them to switch from one action to the other based on the amount of reward. We examined both the behavior of monkeys and the activity of CMA neurons quantitatively by constructing a hybrid reinforcement learning model incorporating context-based and outcome-based action values into a new action value. We found that CMAr neurons encoded the context-based action value by increasing or decreasing their firing rates gradually with the number of repetitions of the same movement (i.e., behavioral context). We also found that CMAr neurons encoded the context-based and outcome-based action values in two distinct time windows at single neuron and population levels. Our findings indicate that the CMAr is involved in behavioral adjustment of action selection by exploiting the behavioral context and not merely by monitoring reward outcome.

Altered relationship between electrophysiological response to errors and gray matter volumes in an extended network for error-processing in pediatric obsessive-compulsive disorder

Pediatric patients with obsessive-compulsive disorder (OCD) show an increased electrophysiological response to errors that is thought to be localized to the posterior medial prefrontal cortex (pMFC). However, the relation of this response, the error-related negativity (ERN), to underlying brain structures remains unknown. In an examination of 20 pediatric OCD patients and 20 healthy youth, we found that more negative ERN amplitude was correlated with lower gray matter (GM) density in pMFC and orbital frontal cortex. The association of the ERN with pMFC gray matter volume was driven by the patient group. In addition, a group difference in the association of ERN with gray matter in right insula was observed, showing an association of these measures in healthy youth (more negative ERN amplitude was associated with lower GM density in insula), but not in patients. These findings provide preliminary evidence linking gray matter volumes in an extended network for error processing to the ERN, and suggest that structural alterations in this network may underlie exaggeration of the ERN in pediatric OCD.

Effects of response force parameters on medial-frontal negativity

The response-related medial-frontal activity (MFN) is often supposed to reflect action-monitoring and error-processing activity. The present force-production task was designed to investigate the effects of two response parameters (i.e., peak response force and time-to-peak, TTP) on the MFN separately. In a 2 × 2 design (high vs. low target force and short vs. long TTP), 22 participants had to produce isometric force pulses to match one of four conditions (e.g., a high target force with a long TTP). Significant main effects of both target force and target TTP were revealed. As previously shown, the MFN amplitude was higher in the high target-force condition than in the low target-force condition. Contrary to the initial expectations, a long TTP had the effect of reducing the MFN amplitude. There was no error-specific effect on the MFN. The force-unit monitoring model (FUMM) is suggested to account for the force- and TTP- specific variations of MFN amplitude, latency and slope.

Noradrenergic versus dopaminergic modulation of impulsivity, attention and monitoring behaviour in rats performing the stop-signal task: possible relevance to ADHD

RATIONALE

Deficient response inhibition is a prominent feature of many pathological conditions characterised by impulsive and compulsive behaviour. Clinically effective doses of catecholamine reuptake inhibitors are able to improve such inhibitory deficits as measured by the stop-signal task (SST) in humans and other animals. However, the precise therapeutic mode of action of these compounds in terms of their relative effects on dopamine (DA) and noradrenaline (NA) systems in prefrontal cortical and striatal regions mediating attention and cognitive control remains unclear.

OBJECTIVES

We sought to fractionate the effects of global catecholaminergic manipulations on SST performance by using receptor-specific compounds for NA or DA. The results are described in terms of the effects of modulating specific receptor subtypes on various behavioural measures such as response inhibition, perseveration, sustained attention, error monitoring and motivation.

RESULTS

Blockade of α2-adrenoceptors improved sustained attention and response inhibition, whereas α1 and β1/2 adrenergic receptor antagonists disrupted go performance and sustained attention, respectively. No relevant effects were obtained after targeting DA D1, D2 or D4 receptors, while both a D3 receptor agonist and antagonist improved post-error slowing and compulsive nose-poke behaviour, though generally impairing other task measures.

CONCLUSIONS

Our results suggest that the use of specific pharmacological agents targeting α2 and β noradrenergic receptors may improve existing treatments for attentional deficits and impulsivity, whereas DA D3 receptors may modulate error monitoring and perseverative behaviour.

Methylphenidate enhances executive function and optimizes prefrontal function in both health and cocaine addiction

Previous studies have suggested dopamine to be involved in error monitoring/processing, possibly through impact on reinforcement learning. The current study tested whether methylphenidate (MPH), an indirect dopamine agonist, modulates brain and behavioral responses to error, and whether such modulation is more pronounced in cocaine-addicted individuals, in whom dopamine neurotransmission is disrupted. After receiving oral MPH (20 mg) or placebo (counterbalanced), 15 healthy human volunteers and 16 cocaine-addicted individuals completed a task of executive function (the Stroop color word) during functional magnetic resonance imaging (fMRI). During MPH, despite not showing differences on percent accuracy and reaction time, all subjects committed fewer total errors and slowed down more after committing errors, suggestive of more careful responding. In parallel, during MPH all subjects showed reduced dorsal anterior cingulate cortex response to the fMRI contrast error>correct. In the cocaine subjects only, MPH also reduced error>correct activity in the dorsolateral prefrontal cortex (controls instead showed lower error>correct response in this region during placebo). Taken together, MPH modulated dopaminergically innervated prefrontal cortical areas involved in error-related processing, and such modulation was accentuated in the cocaine subjects. These results are consistent with a dopaminergic contribution to error-related processing during a cognitive control task.

Impaired response inhibition in veterans with post-traumatic stress disorder and mild traumatic brain injury

Combat veterans with post-traumatic stress disorder (PTSD) can show impairments in executive control and increases in impulsivity. The current study examined the effects of PTSD on motor response inhibition, a key cognitive control function. A Go/NoGo task was administered to veterans with a diagnosis of PTSD based on semi-structured clinical interview using DSM-IV criteria (n = 40) and age-matched control veterans (n = 33). Participants also completed questionnaires to assess self-reported levels of PTSD and depressive symptoms. Performance measures from the patients (error rates and reaction times) were compared to those from controls. PTSD patients showed a significant deficit in response inhibition, committing more errors on NoGo trials than controls. Higher levels of PTSD and depressive symptoms were associated with higher error rates. Of the three symptom clusters, re-experiencing was the strongest predictor of performance. Because the co-morbidity of mild traumatic brain injury (mTBI) and PTSD was high in this population, secondary analyses compared veterans with PTSD+mTBI (n = 30) to veterans with PTSD only (n = 10). Although preliminary, results indicated the two patient groups did not differ on any measure (p > .88). Since cognitive impairments could hinder the effectiveness of standard PTSD therapies, incorporating treatments that strengthen executive functions might be considered in the future. (JINS, 2012, 18, 1-10).

Anterior cingulate cortex and cognitive control: neuropsychological and electrophysiological findings in two patients with lesions to dorsomedial prefrontal cortex

Whereas neuroimaging studies of healthy subjects have demonstrated an association between the anterior cingulate cortex (ACC) and cognitive control functions, including response monitoring and error detection, lesion studies are sparse and have produced mixed results. Due to largely normal behavioral test results in two patients with medial prefrontal lesions, a hypothesis has been advanced claiming that the ACC is not involved in cognitive operations. In the current study, two comparably rare patients with unilateral lesions to dorsal medial prefrontal cortex (MPFC) encompassing the ACC were assessed with neuropsychological tests as well as Event-Related Potentials in two experimental paradigms known to engage prefrontal cortex (PFC). These included an auditory Novelty Oddball task and a visual Stop-signal task. Both patients performed normally on the Stroop test but showed reduced performance on tests of learning and memory. Moreover, altered attentional control was reflected in a diminished Novelty P3, whereas the posterior P3b to target stimuli was present in both patients. The error-related negativity, which has been hypothesized to be generated in the ACC, was present in both patients, but alterations of inhibitory behavior were observed. Although interpretative caution is generally called for in single case studies, and the fact that the lesions extended outside the ACC, the findings nevertheless suggest a role for MPFC in cognitive control that is not restricted to error monitoring.

Event-rate effects in the flanker task: ERPs and task performance in children with and without AD/HD

Demanding tasks require a greater amount of effort, in which case individuals are required to alter their energetic-state to a level appropriate to perform the task. According to the Cognitive-Energetic Model (CEM), children with AD/HD are unable to effectively modulate their energetic state, leading to task underperformance. Using an Eriksen flanker task with varying event-rates, the current study compared the ability of typically-developing children and children with AD/HD to modulate their energetic state. In line with the CEM, it was predicted that children with AD/HD would underperform in the fast and slow event-rates. Results indicated that the groups did not differ in commission errors (i.e., incorrect responses). However, children with AD/HD made more omission errors to incongruent stimuli at the fast and slow event-rates, compared to controls. N2 amplitude was significantly larger for the AD/HD than control group in the slow event-rate. It is concluded that the energetic state modulation dysfunction in children with AD/HD results in an inability to attend to the task, as opposed to an inability to perform the task itself. Furthermore, these task performance differences did not manifest in either the N2 or P3 ERP components. Therefore, inattention in children with AD/HD may have its locus in response preparation, as opposed to stimulus processing, but more research is required to validate these conjectures.

Learning from experience: event-related potential correlates of reward processing, neural adaptation, and behavioral choice

To behave adaptively, we must learn from the consequences of our actions. Studies using event-related potentials (ERPs) have been informative with respect to the question of how such learning occurs. These studies have revealed a frontocentral negativity termed the feedback-related negativity (FRN) that appears after negative feedback. According to one prominent theory, the FRN tracks the difference between the values of actual and expected outcomes, or reward prediction errors. As such, the FRN provides a tool for studying reward valuation and decision making. We begin this review by examining the neural significance of the FRN. We then examine its functional significance. To understand the cognitive processes that occur when the FRN is generated, we explore variables that influence its appearance and amplitude. Specifically, we evaluate four hypotheses: (1) the FRN encodes a quantitative reward prediction error; (2) the FRN is evoked by outcomes and by stimuli that predict outcomes; (3) the FRN and behavior change with experience; and (4) the system that produces the FRN is maximally engaged by volitional actions.

Social deviance activates the brain's error-monitoring system

Social psychologists have long noted the tendency for human behavior to conform to social group norms. This study examined whether feedback indicating that participants had deviated from group norms would elicit a neural signal previously shown to be elicited by errors and monetary losses. While electroencephalograms were recorded, participants (N = 30) rated the attractiveness of 120 faces and received feedback giving the purported average rating made by a group of peers. The feedback was manipulated so that group ratings either were the same as a participant's rating or deviated by 1, 2, or 3 points. Feedback indicating deviance from the group norm elicited a feedback-related negativity, a brainwave signal known to be elicited by objective performance errors and losses. The results imply that the brain treats deviance from social norms as an error.

Is conflict monitoring supramodal? Spatiotemporal dynamics of cognitive control processes in an auditory Stroop task

The electrophysiological correlates of conflict processing and cognitive control have been well characterized for the visual modality in paradigms such as the Stroop task. Much less is known about corresponding processes in the auditory modality. Here, electroencephalographic recordings of brain activity were measured during an auditory Stroop task, using three different forms of behavioral response (overt verbal, covert verbal, and manual), that closely paralleled our previous visual Stroop study. As was expected, behavioral responses were slower and less accurate for incongruent than for congruent trials. Neurally, incongruent trials showed an enhanced fronto-central negative polarity wave (N(inc)), similar to the N450 in visual Stroop tasks, with similar variations as a function of behavioral response mode, but peaking ~150 ms earlier, followed by an enhanced positive posterior wave. In addition, sequential behavioral and neural effects were observed that supported the conflict-monitoring and cognitive adjustment hypothesis. Thus, while some aspects of the conflict detection processes, such as timing, may be modality dependent, the general mechanisms would appear to be supramodal.

Cognitive control in Russian-german bilinguals

Bilingual speakers are faced with the problem to keep their languages apart, but do so with interindividually varying success. Cognitive control abilities might be an important factor to explain such interindividual differences. Here we compare two late, balanced and highly proficient bilingual groups (mean age 24 years, L1 Russian, L2 German) which were established according to their language control abilities on a bilingual picture-naming task. One group had difficulties to remain in the instructed target language and switched unintentionally to the non-target language ("switchers"), whereas the other group rarely switched unintentionally ("non-switchers"). This group-specific behavior could not be explained by language background, socio-cultural, or demographic variables. Rather, the non-switchers also demonstrated a faster and better performance on four cognitive control tests (Tower of Hanoi, Ruff Figural Fluency Test, Divided Attention, Go/Nogo). Here, we focus on two additional executive function tasks, the Wisconsin Card Sorting Test (WCST) and the Flanker task requiring conflict monitoring and conflict resolution. Non-switchers outperformed switchers with regard to speed and accuracy, and were better at finding and applying the correct rules in the WCST. Similarly, in the Flanker task non-switchers performed faster and better on conflict trials and had a higher correction rate following an error. Event-related potential recordings furthermore revealed a smaller error-related negativity in the non-switchers, taken as evidence for a more efficient self-monitoring system. We conclude that bilingual language performance, in particular switching behavior, is related to performance on cognitive control tasks. Better cognitive control, including conflict monitoring, results in decreased unintentional switching.

Distinct frontal networks are involved in adapting to internally and externally signaled errors

Errors trigger changes in behavior that help individuals adapt to new situations. The dorsal anterior cingulate cortex (dACC) is thought to be central to this response, but more lateral frontal regions are also activated by errors and may make distinct contributions. We investigated error processing by studying 2 distinct error types: commission and timing. Thirty-five subjects performed a version of the Simon Task designed to produce large number of errors. Commission errors were internally recognized and were not accompanied by explicit feedback. In contrast, timing errors were difficult to monitor internally and were explicitly signaled. Both types of error triggered changes in behavior consistent with increased cognitive control. As expected, robust activation within the dACC and bilateral anterior insulae (the Salience Network) was seen for commission errors. In contrast, timing errors were not associated with activation of this network but did activate a bilateral network that included the right ventral attentional system. Common activation for both error types occurred within the pars operculari and angular gyri. These results show that the dACC does not respond to all behaviorally salient errors. Instead, the error-processing system is multifaceted, and control can be triggered independently of the dACC when feedback is unexpected.

Acute alcohol intoxication impairs top-down regulation of Stroop incongruity as revealed by blood oxygen level-dependent functional magnetic resonance imaging

Functional neuroanatomy of executive functions has been delineated in a large number of neuroimaging studies using conflict-inducing tasks. The neural basis of alcohol's effects on cognitive control is poorly understood despite the evidence of impaired ability to evaluate competing demands and to inhibit maladaptive responses. To investigate the effects of moderate intoxication, healthy social drinkers participated in both alcohol (0.60 g/kg ethanol for men, 0.55 g/kg for women) and placebo conditions while being scanned using blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI). A modified four-color Stroop task combined reading and color naming and used manual responses. Twenty subjects (10 women) were instructed to press a button corresponding to the font color except when a word was written in gray in which case they had to respond to the meaning of the word. Alcohol increased reaction times and a tendency to make more errors on incongruent trials. Behavioral indices of alcohol-induced premature responding correlated with the current drinking levels and impulsivity traits, suggesting an interaction between alcohol effects and personality predispositions. A distributed frontoparietal cortical network was activated by incongruity. However, moderate alcohol inebriation selectively attenuated anterior cingulate cortex (ACC) activation during both high-conflict trials and erroneous responses, indicating vulnerability of the regulative function subserved by the ACC. By disrupting top-down, strategic processing, alcohol may interfere with goal-directed behavior, resulting in poor self control. The present results support models proposing that alcohol-induced prefrontal impairments diminish inhibitory control and are modulated by dispositional risk factors and levels of alcohol consumption.

Cerebellar lesions alter performance monitoring on the antisaccade task--an event-related potentials study

Error processing is associated with distinct event-related potential components (ERPs), i.e. the error-related negativity (ERN) which occurs within approximately 150 ms and is typically more pronounced than the correct-response negativity (CRN), and the error positivity (Pe) emerging from about 200 to 400 ms after an erroneous response. The short latency of the ERN suggests that the internal error monitoring system acts on rapidly available central information such as an efference copy signal rather than slower peripheral feedback. The cerebellum has been linked to an internal forward-model which enables online performance monitoring by predicting the sensory consequences of actions, most probably by making use of efference copies. In the present study it was hypothesized that the cerebellum is involved in the fast evaluation of saccadic response accuracy as reflected by the ERN. Error processing on an antisaccade task was investigated in eight patients with focal vascular lesions to the cerebellum and 22 control subjects using ERPs. While error rates were comparable between groups, saccadic reaction times (SRTs) were enhanced in the patients, and the error-correct difference waveforms showed reduced amplitudes for patients relative to controls in the ERN time window. Notably, this effect was mainly driven by an increased CRN in the patients. In the later Pe time window, the difference signal yielded higher amplitudes in patients compared to controls mainly because of smaller Pe amplitudes on correct trials in patients. The altered ERN/CRN pattern suggests that the cerebellum is critically involved in fast classification of saccadic accuracy. Largely intact performance accuracy together with increased SRTs and the altered Pe pattern may indicate a compensatory mechanism presumably related to slower, more conscious aspects of error processing in the patients.

Action effect anticipation: neurophysiological basis and functional consequences

Voluntary actions are thought to be selected with respect to their intended goal. Converging data suggests that medial frontal cortex plays a crucial role in linking actions to their predicted effects. Recent neuroimaging data also suggests that during action selection, the brain pre-activities the representation of the predicted action effect. We review evidence of action effect prediction, both in terms of its neurophysiological basis as well as its functional consequences. By assuming that action preparation includes activation of the predicted sensory consequences of the action, we provide a mechanism to understand sensory attenuation and intentional binding. In this account, sensory attenuation results from more difficult discrimination between the observed action effect and the pre-activation of the predicted effect, as compared to when no (or incorrect) prediction is present. Similarly, a predicted action effect should also reach the threshold of awareness faster (intentional binding), if its perceptual representation is pre-activated. By comparing this potential mechanism to mental imagery and repetition suppression we propose a possible neural basis for the processing of predicted action effects.

Neurocognitive deficits in male alcoholics: an ERP/sLORETA analysis of the N2 component in an equal probability Go/NoGo task

In alcoholism research, studies concerning time-locked electrophysiological aspects of response inhibition have concentrated mainly on the P3 component of the event-related potential (ERP). The objective of the present study was to investigate the N2 component of the ERP to elucidate possible brain dysfunction related to the motor response and its inhibition using a Go/NoGo task in alcoholics. The sample consisted of 78 abstinent alcoholic males and 58 healthy male controls. The N2 peak was compared across group and task conditions. Alcoholics showed significantly reduced N2 peak amplitudes compared to normal controls for Go as well as NoGo task conditions. Control subjects showed significantly larger NoGo than Go N2 amplitudes at frontal regions, whereas alcoholics did not show any differences between task conditions at frontal regions. Standardized low resolution electromagnetic tomography analysis (sLORETA) indicated that alcoholics had significantly lower current density at the source than control subjects for the NoGo condition at bilateral anterior prefrontal regions, whereas the differences between groups during the Go trials were not statistically significant. Furthermore, NoGo current density across both groups revealed significantly more activation in bilateral anterior cingulate cortical (ACC) areas, with the maximum activation in the right cingulate regions. However, the magnitude of this difference was much less in alcoholics compared to control subjects. These findings suggest that alcoholics may have deficits in effortful processing during the motor response and its inhibition, suggestive of possible frontal lobe dysfunction.

Modeling conflict and error in the medial frontal cortex

Despite intensive study, the role of the dorsal medial frontal cortex (dMFC) in error monitoring and conflict processing remains actively debated. The current experiment manipulated conflict type (stimulus conflict only or stimulus and response selection conflict) and utilized a novel modeling approach to isolate error and conflict variance during a multimodal numeric Stroop task. Specifically, hemodynamic response functions resulting from two statistical models that either included or isolated variance arising from relatively few error trials were directly contrasted. Twenty-four participants completed the task while undergoing event-related functional magnetic resonance imaging on a 1.5-Tesla scanner. Response times monotonically increased based on the presence of pure stimulus or stimulus and response selection conflict. Functional results indicated that dMFC activity was present during trials requiring response selection and inhibition of competing motor responses, but absent during trials involving pure stimulus conflict. A comparison of the different statistical models suggested that relatively few error trials contributed to a disproportionate amount of variance (i.e., activity) throughout the dMFC, but particularly within the rostral anterior cingulate gyrus (rACC). Finally, functional connectivity analyses indicated that an empirically derived seed in the dorsal ACC/pre-SMA exhibited strong connectivity (i.e., positive correlation) with prefrontal and inferior parietal cortex but was anti-correlated with the default-mode network. An empirically derived seed from the rACC exhibited the opposite pattern, suggesting that sub-regions of the dMFC exhibit different connectivity patterns with other large scale networks implicated in internal mentations such as daydreaming (default-mode) versus the execution of top-down attentional control (fronto-parietal).

Theta lingua franca: a common mid-frontal substrate for action monitoring processes

We present evidence that a multitude of mid-frontal event-related potential (ERP) components partially reflect a common theta band oscillatory process. Specifically, mid-frontal ERP components in the N2 time range and error-related negativity time range are parsimoniously characterized as reflections of theta band activities. Forty participants completed three different tasks with varying stimulus-response demands. Permutation tests were used to identify the dominant time-frequency responses of stimulus- and response-locked conditions as well as the enhanced responses to novelty, conflict, punishment, and error. A dominant theta band feature was found in all conditions, and both ERP component amplitudes and theta power measures were similarly modulated by novelty, conflict, punishment, and error. The findings support the hypothesis that generic and reactive medial prefrontal cortex processes are parsimoniously reflected by theta band activities.

Joint ICA of ERP and fMRI during error-monitoring

The anterior cingulate cortex (ACC) is commonly separated into two functional divisions: the cognitive division, which lies in the caudal region and the affective division, which lies in the rostral region of the ACC. Both regions of the ACC are engaged during error-monitoring tasks; however, little is known about the temporal sequencing associated with cognition and affective processes during error-monitoring. Here we use joint Independent Component Analysis (jICA) to couple event-related potential (ERP) time courses and functional magnetic resonance imaging (fMRI) spatial maps to examine the spatio-temporal stages of engagement in the two divisions of the ACC during error-monitoring. Consistent with hypotheses, two of the five significant spatio-temporal components identified by jICA revealed that the error-related negativity (ERN) ERP was associated with distinct spatial fMRI patterns in the ACC. The ERN(1) was associated with activity in the caudal ACC and lateral prefrontal cortex (lPFC) while the ERN(2) was associated with activity in the rostral ACC. These results suggest that during error-monitoring the caudal ACC and lPFC engage prior to the rostral ACC. These results suggest that cognition precedes affect during error-monitoring.

Altered error processing following vascular thalamic damage: evidence from an antisaccade task

Event-related potentials (ERP) research has identified a negative deflection within about 100 to 150 ms after an erroneous response – the error-related negativity (ERN) - as a correlate of awareness-independent error processing. The short latency suggests an internal error monitoring system acting rapidly based on central information such as an efference copy signal. Studies on monkeys and humans have identified the thalamus as an important relay station for efference copy signals of ongoing saccades. The present study investigated error processing on an antisaccade task with ERPs in six patients with focal vascular damage to the thalamus and 28 control subjects. ERN amplitudes were significantly reduced in the patients, with the strongest ERN attenuation being observed in two patients with right mediodorsal and ventrolateral and bilateral ventrolateral damage, respectively. Although the number of errors was significantly higher in the thalamic lesion patients, the degree of ERN attenuation did not correlate with the error rate in the patients. The present data underline the role of the thalamus for the online monitoring of saccadic eye movements, albeit not providing unequivocal evidence in favour of an exclusive role of a particular thalamic site being involved in performance monitoring. By relaying saccade-related efference copy signals, the thalamus appears to enable fast error processing. Furthermore early error processing based on internal information may contribute to error awareness which was reduced in the patients.

Is comprehension necessary for error detection? A conflict-based account of monitoring in speech production

Despite the existence of speech errors, verbal communication is successful because speakers can detect (and correct) their errors. The standard theory of speech-error detection, the perceptual-loop account, posits that the comprehension system monitors production output for errors. Such a comprehension-based monitor, however, cannot explain the double dissociation between comprehension and error-detection ability observed in the aphasic patients. We propose a new theory of speech-error detection which is instead based on the production process itself. The theory borrows from studies of forced-choice-response tasks the notion that error detection is accomplished by monitoring response conflict via a frontal brain structure, such as the anterior cingulate cortex. We adapt this idea to the two-step model of word production, and test the model-derived predictions on a sample of aphasic patients. Our results show a strong correlation between patients' error-detection ability and the model's characterization of their production skills, and no significant correlation between error detection and comprehension measures, thus supporting a production-based monitor, generally, and the implemented conflict-based monitor in particular. The successful application of the conflict-based theory to error-detection in linguistic, as well as non-linguistic domains points to a domain-general monitoring system.

Anosognosia in neurodegenerative disease

Patients with neurological disorders are often partially or completely unaware of the deficits caused by their disease. This impairment is referred to as anosognosia, and it is very common in neurodegenerative disease, particularly in frontotemporal dementia. Anosognosia has significant impacts on function and quality of life for patients with neurodegenerative disease and their caregivers, but the phenomenon has received little formal study, especially in non-Alzheimer's (non-AD) dementias. Furthermore, few studies have attempted to systematically verify the potential role of specific cognitive impairments in producing anosognosia. As a result, the mechanisms underlying this phenomenon are poorly understood. Episodic memory likely plays an important role. In addition, the frontal lobe systems are important for intact self-awareness, but the most relevant frontal functions have not been identified. Motivation required to engage in self-monitoring and emotional activation marking errors as significant are often-overlooked aspects of performance monitoring that may underlie anosognosia in some patients. The present review offers a working model that incorporates these functions and stipulates specific processes that may be important for awareness of changes in one's abilities. Specification of the specific processes whose potential failure results in anosognosia can establish a roadmap for future studies.

The integration of negative affect, pain and cognitive control in the cingulate cortex

It has been argued that emotion, pain and cognitive control are functionally segregated in distinct subdivisions of the cingulate cortex. However, recent observations encourage a fundamentally different view. Imaging studies demonstrate that negative affect, pain and cognitive control activate an overlapping region of the dorsal cingulate--the anterior midcingulate cortex (aMCC). Anatomical studies reveal that the aMCC constitutes a hub where information about reinforcers can be linked to motor centres responsible for expressing affect and executing goal-directed behaviour. Computational modelling and other kinds of evidence suggest that this intimacy reflects control processes that are common to all three domains. These observations compel a reconsideration of the dorsal cingulate's contribution to negative affect and pain.

Functional networks for cognitive control in a stop signal task: independent component analysis

Cognitive control is a critical executive function of the human brain. Many studies have combined general linear modeling and the stop signal task (SST) to delineate the component processes of cognitive control. For instance, by contrasting stop success (SS) and stop error (SE) trials in the SST, investigators examined the neural processes underlying stop signal inhibition (SS > SE) and error processing (SE > SS). To complement this parameterized approach, here, we employed a data-driven method--independent component analysis (ICA)--to elucidate neural networks and the relationship between neural networks subserving cognitive control. In 59 adults performing the SST during fMRI, we characterized six independent components with ICA. These functional networks, temporally sorted for go success, SS, and SE trials as the events of interest, included a motor cortical network for motor preparation and execution; a right fronto-parietal network for attentional monitoring; a left fronto-parietal network for response inhibition; a midline cortico-subcortical network for error processing; a cuneus-precuneus network for behavioral engagement; and a "default" network for self-referential processing. Across subjects the event-associated weights of these functional networks showed a distinct pattern of correlation. These results provide new insight into the component processes of cognitive control.

Poor decision-making by chronic marijuana users is associated with decreased functional responsiveness to negative consequences

Chronic marijuana users (MJ Users) perform poorly on the Iowa Gambling Task (IGT), a complex decision-making task in which monetary wins and losses guide strategy development. This functional magnetic resonance imaging (MRI) study sought to determine if the poor performance of MJ Users was related to differences in brain activity while evaluating wins and losses during the strategy development phase of the IGT. MJ Users (16) and Controls (16) performed a modified IGT in an MRI scanner. Performance was tracked and functional activity in response to early wins and losses was examined. While the MJ Users continued to perform poorly at the end of the task, there was no difference in group performance during the initial strategy development phase. During this phase, before the emergence of behavioral differences, Controls exhibited significantly greater activity in response to losses in the anterior cingulate cortex, medial frontal cortex, precuneus, superior parietal lobe, occipital lobe and cerebellum as compared to MJ Users. Furthermore, in Controls, but not MJ Users, the functional response to losses in the anterior cingulate cortex, ventral medial prefrontal cortex and rostral prefrontal cortex positively correlated with performance over time. These data suggest MJ Users are less sensitive to negative feedback during strategy development.

To choose or to avoid: age differences in learning from positive and negative feedback

In this study, we investigated whether older adults learn more from bad than good choices than younger adults and whether this is reflected in the error-related negativity (ERN). We applied a feedback-based learning task with two learning conditions. In the positive learning condition, participants could learn to choose responses that lead to monetary gains, whereas in the negative learning condition, they could learn to avoid responses that lead to monetary losses. To test the stability of learning preferences, the task involved a reversal phase in which stimulus-response assignments were inverted. Negative learners were defined as individuals that performed better in the negative than in the positive learning condition (and vice versa for positive learners). The behavioral data showed strong individual differences in learning from positive and negative outcomes that persisted throughout the reversal phase and were more pronounced for older than younger adults. Older negative learners showed a stronger tendency to avoid negative outcomes than younger negative learners. However, contrary to younger adults, this negative learning bias was not associated with a larger ERN, suggesting that avoidance learning in older negative learners might be decoupled from error processing. Furthermore, older adults showed learning impairments compared to younger adults. The ERP analyses suggest that these impairments reflect deficits in the ability to build up relational representations of ambiguous outcomes.

How Monitoring Other’s Actions Influences One’s Own Performance

Monitoring of one’s own and other’s performance during social interactions is crucial to efficiently adapt our behavior and to optimize task performance. In the present study we investigated to what extent social factors can modulate behavioral adjustments in performance. For this purpose, participants executed a flanker task and alternated either with a computer program or with a human partner in cooperative and competitive contexts. Modulations in reaction times (RTs) (post-error slowing) and error rates (post-error accuracy) after error observation were analyzed. The results revealed that these behavioral measures were differently affected by the social manipulations. Post-error slowing was modulated by the social context (cooperation vs. competition), while post-error accuracy was sensitive to the nature of the agent involved in the interaction (human vs. computer). The present findings provide evidence that behavioral adaptations in RTs and accuracy following error observation dissociate and are sensitive to different features of the social situation.

Error-related medial frontal theta activity predicts cingulate-related structural connectivity

Studies on electrophysiological signatures of error processing have focused on the medial frontal cortex, although widespread neuroanatomical networks support error/action monitoring. Here, electrophysiological responses to errors were combined with structural white matter diffusion tensor imaging (DTI) to investigate the long-range anatomical networks that support error processing. The approach taken here was to link individual differences in error-related EEG responses to individual differences in white matter connectional anatomy. Twenty subjects performed a speeded instructed choice task (a variant of the Simon task) designed to elicit response errors, and also underwent DTI scanning in a separate session. In the EEG data, significantly enhanced theta (4-8 Hz) oscillations were observed over medial frontal electrodes (centered on FCz) during response errors. Mid-frontal scalp sites (likely reflecting medial frontal cortex activity) also functioned as a strong "hub" for information flow, measured through theta-band phase synchronization degree. Next, a dipole source of the error-related theta-band activity was localized for each subject, accounting for approximately 80% of the topographical variance. Correlating individual differences in medial frontal theta dynamics with white matter tracts linking these dipole sources to the rest of the brain revealed that subjects with stronger error-related theta also had stronger white matter connectivity with the ventral striatum and inferior frontal gyrus. Further, subjects in whom medial frontal regions acted as a stronger synchronization "hub" had stronger connectivity between the dipole source location and the corpus callosum and dorsomedial prefrontal white matter pathways. These findings provide novel evidence for the role of widespread fronto-striatal networks in monitoring actions and signaling behavioral errors.

Impaired conflict monitoring in Parkinson's disease patients during an oculomotor redirect task

Fallibility is inherent in human cognition and so a system that will monitor performance is indispensable. While behavioral evidence for such a system derives from the finding that subjects slow down after trials that are likely to produce errors, the neural and behavioral characterization that enables such control is incomplete. Here, we report a specific role for dopamine/basal ganglia in response conflict by accessing deficits in performance monitoring in patients with Parkinson's disease. To characterize such a deficit, we used a modification of the oculomotor countermanding task to show that slowing down of responses that generate robust response conflict, and not post-error per se, is deficient in Parkinson's disease patients. Poor performance adjustment could be either due to impaired ability to slow RT subsequent to conflicts or due to impaired response conflict recognition. If the latter hypothesis was true, then PD subjects should show evidence of impaired error detection/correction, which was found to be the case. These results make a strong case for impaired performance monitoring in Parkinson's patients.

Distinct structural changes underpin clinical phenotypes in patients with Gilles de la Tourette syndrome

Gilles de la Tourette syndrome is a childhood-onset neurodevelopmental disorder characterized by tics that are often associated with psychiatric co-morbidities. The clinical heterogeneity of Gilles de la Tourette syndrome has been attributed to the disturbance of functionally distinct cortico-striato-thalamo-cortical circuits, but this remains to be demonstrated. The aim of this study was to determine the structural correlates of the diversity of symptoms observed in Gilles de la Tourette syndrome. We examined 60 adult patients and 30 age- and gender-matched control subjects using cortical thickness measurement and 3 T high-resolution T(1)-weighted images. Patients were divided into three clinical subgroups: (i) simple tics; (ii) simple and complex tics and (iii) tics with associated obsessive-compulsive disorders. Patients with Gilles de la Tourette syndrome had reduced cortical thickness in motor, premotor, prefrontal and lateral orbito-frontal cortical areas. The severity of tics was assessed using the Yale Global Tic Severity Scale and correlated negatively with cortical thinning in these regions, as well as in parietal and temporal cortices. The pattern of cortical thinning differed among the clinical subgroups of patients. In patients with simple tics, cortical thinning was mostly found in primary motor regions. In patients with simple and complex tics, thinning extended into larger premotor, prefrontal and parietal regions. In patients with associated obsessive-compulsive disorders, there was a trend for reduced cortical thickness in the anterior cingulate cortex and hippocampal morphology was altered. In this clinical subgroup, scores on the Yale-Brown Obsessive-Compulsive Scale correlated negatively with cortical thickness in the anterior cingulate cortex and positively in medial premotor regions. These data support the hypothesis that different symptom dimensions in Gilles de la Tourette syndrome are associated with dysfunction of distinct cortical areas and have clear implications for the current neuroanatomical model of this syndrome.

Functional heterogeneity of conflict, error, task-switching, and unexpectedness effects within medial prefrontal cortex

The last decade has seen considerable discussion regarding a theoretical account of medial prefrontal cortex (mPFC) function with particular focus on the anterior cingulate cortex. The proposed theories have included conflict detection, error likelihood prediction, volatility monitoring, and several distinct theories of error detection. Arguments for and against particular theories often treat mPFC as functionally homogeneous, or at least nearly so, despite some evidence for distinct functional subregions. Here we used functional magnetic resonance imaging (fMRI) to simultaneously contrast multiple effects of error, conflict, and task-switching that have been individually construed in support of various theories. We found overlapping yet functionally distinct subregions of mPFC, with activations related to dominant error, conflict, and task-switching effects successively found along a rostral-ventral to caudal-dorsal gradient within medial prefrontal cortex. Activations in the rostral cingulate zone (RCZ) were strongly correlated with the unexpectedness of outcomes suggesting a role in outcome prediction and preparing control systems to deal with anticipated outcomes. The results as a whole support a resolution of some ongoing debates in that distinct theories may each pertain to corresponding distinct yet overlapping subregions of mPFC.

Resisting motor mimicry: control of imitation involves processes central to social cognition in patients with frontal and temporo-parietal lesions

Perception and execution of actions share a common representational and neural substrate and thereby facilitate unintentional motor mimicry. Controlling automatic imitation is therefore a crucial requirement of such a "shared representational" system. Based on previous findings from neuroimaging, we suggest that resisting motor mimicry recruits the same underlying computational mechanisms also involved in higher-level social cognitive processing, such as self - other differentiation and the representation of mental states. The aim of the present study was to investigate on a behavioral level whether there is a functional association between the inhibition of imitation and tasks, assessing the understanding of mental states and of different perspectives of self and other. In a sample of neuropsychological patients with frontal lesions, a correlation between the ability for mental state attribution and the control of imitation was found, with a similar effect in the control group. Temporo-parietal lesioned patients showed a highly significant correlation between imitative control and visual and cognitive perspective-taking. Even after controlling for executive functions, the results remained significant, indicating the functional specificity of this relationship. These findings provide new insight into the functional processes underlying the control of shared representations and suggest a novel link between embodied and higher-level social cognition.