Stimulus Conflict Research Articles

A computational account of conflict processing during mental imagery.

Previous studies examining conflict processing within the context of a color-word Stroop task have focused on both stimulus and response conflicts. However, it has been unclear whether conflict can emerge independently of stimulus conflict. In this study, a novel arrow-gaze mental-rotation Stroop task was introduced to explore the interplay between conflict processing and mental rotation. A modelling approach was utilized to provide a process-level account of the findings. The results of our Stroop task indicate that conflict can emerge from mental rotation in the absence of stimulus conflict. The strength of this imagery conflict effect decreases and even reverses as mental rotation angles increase. Additionally, it was observed that participants responded more quickly and with greater accuracy to small rather than large face orientations. A comparison of three conflict diffusion models-the diffusion model for conflict tasks (DMC), the dual-stage two-phase model (DSTP), and the shrinking spotlight model (SSP)-yielded consistent support for the DSTP over the DMC and SSP in the majority of instances. The DSTP account of the experimental results revealed an increased nondecision time with increasing mental rotation, a reduction in interference from incompatible stimuli, and an improved drift rate in response selection phase, which suggests enhanced cognitive control. The findings from the model-based analysis provide evidence for a novel interaction between cognitive control and mental rotation.

Conflict in a word-based approach-avoidance task is stronger with positive words.

Valence and motivational direction are linked. We approach good things and avoid bad things, and experience overriding these links as conflicting. Positive valence is more consistently linked with approach than negative valence is linked with avoidance. Therefore, avoiding positive stimuli should produce greater behavioral and neural signs of conflict than approaching negative stimuli. In the present event-related potential study, we tested this assumption by contrasting positive and negative conflict. We used the manikin task, in which we read positive and negative words that they needed to approach and avoid. Consistent with our prediction, positive conflict prolonged reaction times more than negative conflict did. A late (500-1000ms following word onset) event-related potential that we identified as the Conflict slow potential, was only sensitive to positive conflict. The results of this study support the notion that avoiding positive stimuli is more conflicting than approaching negative stimuli. The fact that the conflict slow potential is typically sensitive to response conflict rather than stimulus conflict suggests that the manikin task primarily requires people to override prepotent responses rather than to identify conflicting stimuli. Thus, the present findings also shed light on the psychological processes subserving conflict resolution in the manikin task.

A neurophysiological perspective on the integration between incidental learning and cognitive control

Adaptive behaviour requires interaction between neurocognitive systems. Yet, the possibility of concurrent cognitive control and incidental sequence learning remains contentious. We designed an experimental procedure of cognitive conflict monitoring that follows a pre-defined sequence unknown to participants, in which either statistical or rule-based regularities were manipulated. We show that participants learnt the statistical differences in the sequence when stimulus conflict was high. Neurophysiological (EEG) analyses confirmed but also specified the behavioural results: the nature of conflict, the type of sequence learning, and the stage of information processing jointly determine whether cognitive conflict and sequence learning support or compete with each other. Especially statistical learning has the potential to modulate conflict monitoring. Cognitive conflict and incidental sequence learning can engage in cooperative fashion when behavioural adaptation is challenging. Three replication and follow-up experiments provide insights into the generalizability of these results and suggest that the interaction of learning and cognitive control is dependent on the multifactorial aspects of adapting to a dynamic environment. The study indicates that connecting the fields of cognitive control and incidental learning is advantageous to achieve a synergistic view of adaptive behaviour.

Longitudinal changes in neural gain and its relationship to cognitive control trajectory in young adults with early psychosis

The mixed cognitive outcomes in early psychosis (EP) have important implications for recovery. In this longitudinal study, we asked whether baseline differences in the cognitive control system (CCS) in EP participants would revert toward a normative trajectory seen in healthy controls (HC). Thirty EP and 30 HC undertook functional MRI at baseline using the multi-source interference task—a paradigm that selectively introduces stimulus conflict—and 19 in each group repeated the task at 12 months. Activation of the left superior parietal cortex normalized over time for the EP group, relative to HC, coincident with improvements in reaction time and social-occupational functioning. To examine these group and timepoint differences, we used dynamic causal modeling to infer changes in effective connectivity between regions underlying the MSIT task execution, namely visual, anterior insula, anterior cingulate, and superior parietal cortical regions. To resolve stimulus conflict, EP participants transitioned from an indirect to a direct neuromodulation of sensory input to the anterior insula over timepoints, though not as strongly as HC participants. Stronger direct nonlinear modulation of the anterior insula by the superior parietal cortex at follow-up was associated with improved task performance. Overall, normalization of the CCS through adoption of more direct processing of complex sensory input to the anterior insula, was observed in EP after 12 months of treatment. Such processing of complex sensory input reflects a computational principle called gain control, which appears to track changes in cognitive trajectory within the EP group.

Attentional function and inhibitory control in different substance use disorders

Attentional function in substance use disorder (SUD) is not well understood. To probe attentional function in SUD as a function of primary substance of abuse, we administered the attentional network task (ANT) to 44 individuals with Cocaine Use Disorder (CoUD), 49 individuals with Cannabis Use Disorder (CaUD), 86 individuals with Opioid Use Disorder (OUD), and 107 controls with no SUD, along with the stop-signal task (SST). The ANT quantifies the effects of (temporal) alerting cues and (spatial) orienting cues to reduce reaction time (RT) to targets, as well as probing how conflicting (target-incongruent) stimuli slow RT. The SST quantifies individuals’ ability to inhibit already-initiated motor responses. After controlling for sex representation and age, OUD and CaUD participants showed blunted alerting effects compared to controls, whereas CaUD and CoUD participants showed greater stimulus conflict (flanker) effects. Finally, CoUD participants showed a trend toward increased orienting ability. In SST performance, no SUD group showed a prolonged stop-signal reaction compared to controls. However, the OUD group (and CoUD group at trend level) showed prolonged “go” RT to targets and reduced hit rates. These data indicate differences in attentional function in persons with SUD as a function of the primary substance use.

Sub-optimal modulation of gain by the cognitive control system in young adults with early psychosis

Executive dysfunctions in early psychosis (EP) are subtle but persistent, hindering recovery. We asked whether changes in the cognitive control system (CCS) disrupt the response to increased cognitive load in persons with EP. In all, 30 EP and 30 control participants undertook multimodal MRI. Computational models of structural and effective connectivity amongst regions in the CCS were informed by cortical responses to the multi-source interference task, a paradigm that selectively introduces stimulus conflict. EP participants showed greater activation of CCS regions, including the superior parietal cortex, and were disproportionately slower at resolving stimulus conflict in the task. Computational models of the effective connectivity underlying this behavioral response suggest that the normative (control) group resolved stimulus conflict through an efficient and direct modulation of gain between the visual cortex and the anterior insula (AI). In contrast, the EP group utilized an indirect path, with parallel and multi-region hops to resolve stimulus conflict at the AI. Individual differences in task performance were dependent on initial linear gain modulations in the EP group versus a single nonlinear modulation in the control group. Effective connectivity in the EP group was associated with reduced structural integration amongst those connections critical for task execution. CCS engagement during stimulus conflict is hampered in EP owing to inefficient use of higher-order network interactions, with high tonic gain impeding task-relevant (phasic) signal amplification.

Stimulus and response conflict from a second language: Stroop interference in weakly-bilingual and recently-trained languages

The aim of the present manuscript was to investigate the source of congruency effects in weak bilinguals (Experiment 1) and in early language learning (Experiment 2). In both studies, participants performed a bilingual version of a colour-word Stroop task. The standard finding is slower and less accurate responding when the word and colour are incongruent (e.g., “red” in blue) relative to congruent (e.g., “red” in red). This congruency effect occurs for the distracting colour words from both the first and second language. Both stimulus conflict (i.e., conflict between the meaning of the word and ink colour) and response conflict (i.e., conflict between possible response options) contribute to first-language congruency effects. According to some models of early language learning, only one of these two types of conflict should emerge for non-fluent languages. To separate stimulus and response conflict, we used a 2-to-1 keypress assignment manipulation. Interestingly, in one study both stimulus and response conflict were evidenced for the weakly spoken second language (English in native French speakers). In a second study, participants performed a short Croatian colour word learning phase before the Stroop procedure. Stimulus conflict was observed in response times and response conflict in errors for this recently-trained language. These findings suggest that the relatively low-proficient second language words are potent enough to affect semantic identification and response selection.

Perceived conflict may be negative but resolved conflict is not

The current study investigated how exposure to a conflict stimulus influences the judgment of a subsequent stimulus’s valence. We used an affective priming paradigm, presenting a color Stroop stimulus as a prime and a face as a target for an emotion recognition task. When the task for the prime was passive viewing (Experiment 1), congruent primes resulted in faster responses to emotionally positive targets than negative targets. However, this positivity bias disappeared following incongruent primes. In Experiment 2, instead of passive viewing, participants were asked to indicate the congruency of the prime, and the positivity bias was significant following the congruent prime but not following the incongruent prime. In Experiments 3 and 4, participants performed the conventional Stroop task on the prime, therefore resolving the conflict when the prime was incongruent. Experiment 3 adopted an equal proportion of congruent and incongruent primes. Experiment 4 adopted twice as many congruent primes as incongruent primes. In both experiments, the positivity bias was not significant regardless of the congruency of the prime. These results suggest that detecting conflict may interfere with positive affect or promote negative affect, therefore reducing the positivity bias. Once the conflict is resolved, however, the negative valence may disappear.

Target Amplification and Distractor Inhibition: Theta Oscillatory Dynamics of Selective Attention in a Flanker Task

Selective attention is a key mechanism to monitor conflict-related processing and behaviour, by amplifying task-relevant processing and inhibiting task-irrelevant information. Conflict monitoring and resolution is typically associated with brain oscillatory power increase in the theta frequency range (3-8 Hz), as indexed by increased midfrontal theta power. We expand previous findings of theta power increase related to conflict processing and distractor inhibition by considering attentional target amplification to be represented in theta frequency as well. The present study (N = 41) examined EEG oscillatory activities associated with stimulus and response conflict in a lateralized flanker task. Depending on the perceptual (in)congruency and response (in)compatibility of distractor-target associations, resulting stimulus and response conflicts were examined in behavioural and electrophysiological data analyses. Both response and stimulus conflict emerged in RT analysis. Regarding EEG data, response-locked cluster analysis showed an increase of midfrontal theta power related to response conflict. In addition, stimulus-locked cluster analysis revealed early clusters with increased parietal theta power for nonconflicting compared to conflicting trials, followed by increased midfrontal theta power for both stimulus and response conflict. Our results suggest that conflict resolution in the flanker task relies on a combination of target amplification, depicted by parietal theta power increase, and distractor inhibition, indexed by midfrontal theta power increase, for both stimulus and response conflicts. Attentional amplification of sensory target features is discussed with regard to a domain-general conflict monitoring account.

Towards an Integrated Account of Incidental Learning and Cognitive Control

SummaryInteraction between various cognitive systems is imperative in adaptive behaviour. Yet, the possibility of concurrent cognitive control and incidental sequence learning has been contentious. To test possible interrelations, we designed a novel sequential Stroop task. As the competition theory predicted, participants’ responses followed expectations in a Stroop task, however, they did not express control-independent learning of the stimulus-control state regularities. In contrast, statistical learning of stimulus-control state associations was enhanced in high stimulus conflict. Additionally, conflict-related response cost was reduced when the high conflict trials were predictable from the sequence. Thus, cognitive conflict can benefit from incidental sequence learning. Importantly, the EEG results suggest that competition and interaction can determine different stages of information processing. It is the level of conflict, the type of sequence learning, the general task experience, and the stage of information processing which determine whether cognitive conflict and sequence learning support or compete with each other.

Stroop N450 reflects both stimulus conflict and response conflict.

N450 is described as a valid event-related potential indicator of Stroop interference, but the true specific psychological meaning of the Stroop N450 remains obscure. In the present research, we first used a Chinese character incongruent-eligible task and manipulated different types of conflict to investigate whether Stroop N450 reflects stimulus conflict, response conflict or both. The results showed that, only the N450 in the incongruent-eligible condition was more negative than that of the incongruent-ineligible and neutral conditions in the frontal-central area; simultaneously, there was a left parietal-occipital N450 that successively weakened in the incongruent-eligible, incongruent-ineligible and neutral conditions. These results indicate that Stroop N450 reflects both stimulus conflict and response conflict.

Intact Stimulus-Response Conflict Processing in ADHD-Multilevel Evidence and Theoretical Implications.

Attention-deficit-hyperactivity disorder (ADHD) is closely associated with deficits in cognitive control. It seems, however, that the degree of deficits strongly depends on the examined subprocess, with the resolution of stimulus–stimulus conflicts being particularly difficult for patients with ADHD. The picture is far less clear regarding stimulus–response conflicts. The current study provides multi-level behavioural and neurophysiological data on this type of conflict monitoring in children with ADHD compared to healthy controls. To account for the potentially strong effects of intra-individual variability, electroencephalogram (EEG) signal decomposition methods were used to analyze the data. Crucially, none of the analyses (behavioural, event-related potentials, or decomposed EEG data) show any differences between the ADHD group and the control group. Bayes statistical analysis confirmed the high likelihood of the null hypothesis being true in all cases. Thus, the data provide multi-level evidence showing that conflict monitoring processes are indeed partly intact in ADHD, even when eliminating possible biasing factors such as intra-individual variability. While stimulus–stimulus conflict processing has been shown to be consistently dysfunctional in ADHD, the resolution of stimulus–response conflicts is not deficient in this patient group. In comparison to other studies, the results provide novel theoretical insights into the nature of conflict control deficits in childhood ADHD.

Double dissociation of learned approach-avoidance conflict processing and spatial pattern separation along the dorsoventral axis of the dentate gyrus.

The ventral portion of the rodent hippocampus (HPC; anterior in primates) has been implicated in the detection and resolution of approach-avoidance conflict, which arises when an organism encounters a stimulus that predicts both positive and negative outcomes. Previous work has found differential regulation of approach-avoidance conflict behavior by the CA3 and CA1 subfields, with inhibition of ventral CA3 increasing approach toward conflicting stimuli and inhibition of the ventral CA1 potentiating avoidance. Here, we sought to extend these findings by investigating the role of the dentate gyrus (DG), the input region of the HPC, in learned approach-avoidance conflict processing in rats. Animals were first trained to acquire three different visuotactile cue-outcome associations in separate arms of a Y-maze (appetitive, aversive, and neutral). Postacquisition, they were administered a "conflict test," in which they were presented with a choice between exploring an arm in which the appetitive and aversive cues were concurrently presented (conflict stimulus), and another arm containing the neutral stimulus. GABAR-mediated inactivation of the ventral DG, but not dorsal DG, potentiated approach behavior toward the conflict stimulus, similar to the effects of ventral CA3 inactivation. In contrast, dorsal DG, but not ventral DG, inactivation was found to impair performance on a metric spatial discrimination task, which is commonly used as a test of pattern separation. The findings of this study demonstrate a robust double dissociation between the ventral and dorsal aspects of the DG, in line with previous reports of functional differences along the longitudinal axis of the HPC.

A psychophysiological investigation of the interplay between orienting and executive control during stimulus conflict: A heart rate variability study

BackgroundIt has been hypothesized that resting state cardiac vagal activity (CVA) - an indicator of parasympathetic nervous system activity - is a specific psychophysiological marker of executive control function. Here, we propose an alternative hypothesis - that CVA is associated with early stage attention orientation, promoting the flexible uptake of new information, on which the later operation of such executive control functions depends. We therefore predicted that CVA would predict the interaction between orienting and executive control. This was tested using the revised version of the Attention Network Test (ANT-R) that was developed to distinguish between orienting and executive attention during a stimulus conflict task. MethodsHealthy adults (N = 48) performed the ANT-R and their resting CVA was measured over a 5 min period using ECG recordings. ResultsMultiple regression analyses indicated that, when other factors were controlled for, CVA was more strongly associated with the interaction between the orienting and executive control terms than with either factor individually. ConclusionHigher levels of CVA are specifically implicated in the modulation of executive control by intrinsic orientation operating at early stages of conflict detection. These initial findings of higher CVA on orienting attention in conflict detection need to be replicated in larger samples.

FMRI study of cannabidiol-induced changes in attention control in treatment-resistant epilepsy

Patients with treatment-resistant epilepsy (TRE) frequently exhibit memory and attention deficits that contribute to their poor personal and societal outcomes. We studied the effects of adjunct treatment with pharmaceutical grade cannabidiol (CBD) oral solution (Epidiolex®; Greenwich Biosciences, Inc.) on attention control processes related to stimulus conflict resolution in patients with TRE. Twenty-two patients with TRE underwent 3 T magnetic resonance imaging (MRI) before receiving (PRE) and after achieving a stable dose of CBD (ON). Functional MRI (fMRI) data were collected while patients performed 2 runs of a flanker task (FT). Patients were instructed to indicate via button press the congruent (CON) and incongruent (INC) conditions. We performed t-tests to examine with FT attention control processes at PRE and ON visits and to compare the 2 visits using derived general linear model (GLM) data (INC – CON). We performed generalized psychophysiological interaction (gPPI) analyses to assess changes in condition-based functional connectivity on FT. Median time between fMRI visits was 10 weeks, and median CBD dose at follow-up was 25 mg/kg/d. From PRE to ON, participants experienced improvements in seizure frequency (SF) (p = 0.0009), seizure severity (Chalfont Seizure Severity Scale (CSSS); p < 0.0001), and mood (Total Mood Disturbance (TMD) score from Profile of Mood States (POMS); p = 0.0026). Repeated measures analysis of variance showed nonsignificant improvements in executive function from 34.6 (23.5)% to 41.9 (22.4)% CON accuracy and from 34.2 (25.7)% to 37.6 (24.4)% INC accuracy (p = 0.199). Change in CON accuracy was associated with change in INC accuracy (rS = 0.81, p = 0.0005). Participants exhibited CBD-induced increases in fMRI activation in the right superior frontal gyrus (SFG) and right insula/middle frontal gyrus (MFG) and decrease in activation for both regions at ON relative to PRE (corrected p = 0.05). The subset of patients who improved in FT accuracy with CBD showed a negative association between change in right insula/MFG activation and change in accuracy for the INC condition (rS = −0.893, p = 0.0068). The gPPI analysis revealed a CBD-induced decrease in condition-based functional connectivity differences for the right SFG seed region (corrected p = 0.05). Whole-brain regression analysis documented a negative association of change in right insula/MFG condition-based connectivity with change in INC accuracy (corrected p = 0.005). Our results suggest that CBD modulates attention control processing in patients with TRE by reducing right SFG and right insula/MFG activation related to stimulus conflict resolution and by dampening differences in condition-based functional connectivity of the right SFG. Our study is the first to provide insight into how CBD affects the neural substrates involved in attention processing and how modulation of the activity and functional connectivity related to attentional control processes in the right insula/MFG may be working to improve cognitive performance in TRE.

Skilled musicians are indeed subject to the McGurk effect

The McGurk effect is an illusion whereby speech sounds are often mis-categorized when the auditory cues in the stimulus conflict with the visual cues from the speaker's face. A recent study claims that ‘skilled musicians are not subject to’ this effect. It is not clear, however, if this is intended to mean that skilled musicians do not experience the McGurk effect at all, or if they just experience it to a lesser magnitude than non-musicians. The study also does not statistically demonstrate either of these conclusions, as it does report a numerical (albeit non-significant) McGurk effect for musicians and does not report a significant difference between musicians' and non-musicians’ McGurk effect sizes. This article reports a pre-registered, higher-power replication of that study (using twice the sample size and changing from a between- to a within-participants manipulation). Contrary to the original study's conclusion, we find that musicians do show a large and statistically significant McGurk effect and that their effect is no smaller than that of non-musicians.

Do the rat anterior thalamic nuclei contribute to behavioural flexibility?

The rodent anterior thalamic nuclei (ATN) are vital for spatial memory. A consideration of their extensive frontal connections suggests that these nuclei may also subserve non-spatial functions. The current experiments explored the importance of the ATN for different aspects of behavioural flexibility, including their contribution to tasks typically associated with frontal cortex. In Experiment 1, rats with ATN lesions were tested on a series of response and visual discriminations in an operant box and, subsequently, in a water tank. The tasks included assessments of reversal learning as well switches between each discrimination dimension. Results revealed a mild and transient deficit on the operant task that was not specific to any stage of the procedure. In the water tank, the lesion animals were impaired on the reversal of a spatial discrimination but did not differ from controls on any other measure. Experiment 2 examined the impact of ATN damage on a rodent analogue of the ‘Stroop’, which assesses response choice during stimulus conflict. The lesion animals successfully acquired this task and were able to use contextual information to disambiguate conflicting cue information. However, responding during the initial presentation of conflicting cue information was affected by the lesion. Taken together, these results suggest that the ATN are not required for aspects of behavioural flexibility (discrimination learning, reversals or high-order switches) typically associated with the rat medial prefrontal cortex. The results from Experiment 2 suggest that the non-spatial functions of the ATN may be more aligned with those of the anterior cingulate cortex.

On the effects of tyrosine supplementation on interference control in a randomized, double-blind placebo-control trial

Exerting cognitive control is an effortful endeavor that is strongly modulated by the availability of dopamine (DA) and norepinephrine (NE), which are both synthesized from the amino acid precursor tyrosine. Supplementing tyrosine may increase the synthesis of both catecholamines. This has been suggested to improve executive functioning and potentially even counteract depletion effects in this domain. Yet, it has remained unclear whether tyrosine also improves interference control and whether subliminally and consciously triggered response conflicts are subject to the same modulation.We investigated this question in a double-blind intra-individual study design. N = 26 young healthy subjects performed two consecutive cognitive control tasks that triggered automatic incorrect response tendencies; once with tyrosine supplementation and once with a placebo. The results show that tyrosine decreased the size of consciously perceived conflicts in a Simon Task, but not a Flanker task, thus suggesting that stimulus–response conflicts might be modulated differently from stimulus–stimulus conflicts. At the same time, tyrosine supplementation increased the size of subliminally triggered conflicts whenever a different, consciously perceived conflict was also present. This suggests that control-related DA and NE release may increase visuo-motor priming, especially when no conflict-specific top-down control may be triggered to counteract subliminal priming effects. Also, these subliminal conflicts might be aggravated by concurrent control investments in other kinds of conflict. Taken together, our data suggest that beneficial effects of tyrosine supplementation do not require depletion effects, but may be limited to situations where we consciously perceive a conflict and the associated need for conflict-specific control.

Context Modulates Congruency Effects in Selective Attention to Social Cues.

Head and gaze directions are used during social interactions as essential cues to infer where someone attends. When head and gaze are oriented toward opposite directions, we need to extract socially meaningful information despite stimulus conflict. Recently, a cognitive and neural mechanism for filtering-out conflicting stimuli has been identified while performing non-social attention tasks. This mechanism is engaged proactively when conflict is anticipated in a high proportion of trials and reactively when conflict occurs infrequently. Here, we investigated whether a similar mechanism is at play for limiting distraction from conflicting social cues during gaze or head direction discrimination tasks in contexts with different probabilities of conflict. Results showed that, for the gaze direction task only (Experiment 1), inverse efficiency (IE) scores for distractor-absent trials (i.e., faces with averted gaze and centrally oriented head) were larger (indicating worse performance) when these trials were intermixed with congruent/incongruent distractor-present trials (i.e., faces with averted gaze and tilted head in the same/opposite direction) relative to when the same distractor-absent trials were shown in isolation. Moreover, on distractor-present trials, IE scores for congruent (vs. incongruent) head-gaze pairs in blocks with rare conflict were larger than in blocks with frequent conflict, suggesting that adaptation to conflict was more efficient than adaptation to infrequent events. However, when the task required discrimination of head orientation while ignoring gaze direction, performance was not impacted by both block-level and current trial congruency (Experiment 2), unless the cognitive load of the task was increased by adding a concurrent task (Experiment 3). Overall, our study demonstrates that during attention to social cues proactive cognitive control mechanisms are modulated by the expectation of conflicting stimulus information at both the block- and trial-sequence level, and by the type of task and cognitive load. This helps to clarify the inherent differences in the distracting potential of head and gaze cues during speeded social attention tasks.

Neural and Behavioral Correlates of Attentional Inhibition Training and Perceptual Discrimination Training in a Visual Flanker Task.

Two groups of healthy young adults were exposed to 3 weeks of cognitive training in a modified version of the visual flanker task, one group trained to discriminate the target (discrimination training) and the other group to ignore the flankers (inhibition training). Inhibition training, but not discrimination training, led to significant reductions in both Garner interference, indicating improved selective attention, and in Stroop interference, indicating more efficient resolution of stimulus conflict. The behavioral gains from training were greatest in participants who showed the poorest selective attention at pretest. Electrophysiological recordings revealed that inhibition training increased the magnitude of Rejection Positivity (RP) to incongruent distractors, an event-related potential (ERP) component associated with inhibitory control. Source modeling of RP uncovered a dipole in the medial frontal gyrus for those participants receiving inhibition training, but in the cingulate gyrus for those participants receiving discrimination training. Results suggest that inhibitory control is plastic; inhibition training improves conflict resolution, particularly in individuals with poor attention skills.