Stop-signal Inhibition Research Articles

343. Effects of Natural and Experimental Withdrawal From Estradiol or Progesterone on Stop-Signal Inhibition Across the Menstrual Cycle in Patients With Suicidal Ideation

343. Effects of Natural and Experimental Withdrawal From Estradiol or Progesterone on Stop-Signal Inhibition Across the Menstrual Cycle in Patients With Suicidal Ideation

Temporal Dynamics of Event-Related Potentials during Inhibitory Control Characterize Age-Related Neural Compensation.

Aging is accompanied by frontal lobe and non-dominant hemisphere recruitment that supports executive functioning, such as inhibitory control, which is crucial to all cognitive functions. However, the spatio-temporal sequence of processing underlying successful inhibition and how it changes with age is understudied. Thus, we capitalized on the temporal precision of event-related potentials (ERPs) to assess the functional lateralization of N200 (conflict monitoring) and P300 (inhibitory performance evaluation) in young and healthy older adults during comparably performed successful stop-signal inhibition. We additionally used temporal principal components analysis (PCA) to further interrogate the continuous spatio-temporal dynamics underlying N200 and P300 activation for each group. Young adults demonstrated left hemisphere-dominant N200, while older adults demonstrated overall larger amplitudes and right hemisphere dominance. N200 activation was explained by a single PCA factor in both age groups, but with a more anterior scalp distribution in older adults. The P300 amplitudes were larger in the right hemisphere in young, but bilateral in old, with old larger than young in the left hemisphere. P300 was also explained by a single factor in young adults but by two factors in older adults, including distinct parieto-occipital and anterior activation. These findings highlight the differential functional asymmetries of conflict monitoring (N200) and inhibitory evaluation and adaptation (P300) processes and further illuminate unique age-related spatio-temporal recruitment patterns. Older adults demonstrated lateralized recruitment during conflict processing and bilateral recruitment during evaluation and adaptation, with anterior recruitment common to both processes. These fine-grained analyses are critically important for more precise understanding of age-related compensatory activation.

Working memory and behavioral inhibition in children with attention-deficit/hyperactivity disorder (ADHD): an examination of varied central executive demands, construct overlap, and task impurity

ABSTRACTThe stop-signal paradigm is the premier metric of behavioral inhibition in contemporary attention-deficit/hyperactivity disorder (ADHD) research. The stop-signal paradigm’s choice-reaction time component, however, arguably places greater demands on working memory processes (e.g., controlled-focused attention) relative to alternative inhibition metrics (i.e., go/no-go (GNG) tasks), and consequently obscures conclusions about inhibition and working memory deficits in affected children. The current study, therefore, aimed to determine whether shared variance between stop-signal behavioral inhibition and working memory performance in children with ADHD reflects overlap between the working memory and inhibition constructs or insufficient specificity of the stop-signal paradigm. Fifty-five children (8–12 years) with and without ADHD were administered established phonological (PH) and visuospatial (VS) working memory measures, as well as stop-signal and GNG tasks that vary with respect to demands on controlled-focused attention. Although working memory and GNG performance each uniquely predicted children’s inattention, stop-signal task performance was not a significant predictor of unique variance in inattention, above and beyond variance associated with working memory. Collectively, these findings suggest that performance on the stop-signal task, compared to the GNG task, is confounded by greater demands associated with working memory and consequently reflects an impure estimate of the inhibition construct.

The motor inhibition system in Parkinson's disease with levodopa-induced dyskinesias.

Parkinson's disease is primarily a disorder of response initiation characterized by an excessive motor inhibition, whereas levodopa-induced dyskinesias are clearly a clinical expression of disinhibition of movements. That levodopa-induced dyskinesias are linked to dysfunctions of inhibitory brain network has recently been proposed, but no investigation of behavioral performance during action inhibition task in these patients has been published. Twenty-four Parkinson's disease patients with or without levodopa-induced dyskinesias tested on or off their medications underwent functional magnetic resonance imaging investigation during the execution of a stop-signal inhibition task. In particular, we were interested in evaluating the neural correlates of stop-related conditions: StopInhibit task (in which patients had to successfully inhibit their responses) and StopRespond task (Stop trials with erroneous button press). Both tasks were compared against Go trials. Levodopa intake in dyskinetic patients tended to worsen inhibitory control during the StopInhibit task, while significantly affecting the ability to monitor motor responses when patients failed to stop (StopRespond task). Functional analysis showed that, during the StopInhibit task, dyskinetic patients were characterized by decreased activity of the right inferior frontal cortex after levodopa intake, whereas patients without dyskinesias showed a reverse effect. A similar group × levodopa interaction effect was detected in the medial frontal cortex during the execution of the StopRespond task, in which dyskinetic patients showed increased activity after dopaminergic therapy Our study demonstrated that levodopa intake in dyskinetic patients tends to alter the functioning of some parts of the neural network involved in motor inhibition.

Independent component analysis of functional networks for response inhibition: Inter-subject variation in stop signal reaction time.

Cognitive control is a critical executive function. 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 regional responses to stop signal inhibition. In contrast to this parameterized approach, independent component analysis (ICA) elucidates brain networks subserving cognitive control. In our earlier work of 59 adults performing the SST during fMRI, we characterized six independent components (ICs). However, none of these ICs correlated with stop signal performance, raising questions about their behavioral validity. Here, in a larger sample (n = 100), we identified and explored 23 ICs for correlation with the stop signal reaction time (SSRT), a measure of the efficiency of response inhibition. At a corrected threshold (P < 0.0005), a paracentral lobule-midcingulate network and a left inferior parietal-supplementary motor-somatomotor network showed a positive correlation between SE beta weight and SSRT. In contrast, a midline cerebellum-thalamus-pallidum network showed a negative correlation between SE beta weight and SSRT. These findings suggest that motor preparation and execution prolongs the SSRT, likely via an interaction between the go and stop processes as suggested by the race model. Behaviorally, consistent with this hypothesis, the difference in G and SE reaction times is positively correlated with SSRT across subjects. These new results highlight the importance of cognitive motor regions in response inhibition and support the utility of ICA in uncovering functional networks for cognitive control in the SST.

The relationship between the development of response inhibition and intelligence in preschool children.

Building on the theoretical framework that intellectual behavior relies on one's ability to process both task-relevant and task-irrelevant information, this study aimed to empirically investigate the association of response inhibition with intelligence in preschool children's development. In a sample of 152 typically developing children aged between 3.6 and 6.6 years, we found evidence that suggests that inhibitory control is linked to age-related differences in intelligence. Stop-signal inhibition improved at a rate similar to the age-related changes in Verbal IQ. Components of variance analyses revealed that stop-signal reaction time predicted a larger proportion of the age-related variance in children's verbal intelligence than non-age-related variance. Results are discussed with respect to possible explanations for this intriguing relationship between response inhibition and the verbal aspects of intelligence.

Functional Brain Activation Associated with Inhibitory Control Deficits in Older Adults.

In young adults, canceling an initiated action depends on the right inferior frontal cortex (IFC), presupplementary motor area (preSMA), and the basal ganglia. Older adults show response inhibition deficits, but how this relates to functional brain activation remains unclear. Using event-related functional magnetic resonance imaging, we tested whether older adults (N = 20) exhibit overactivation during stop-signal inhibition as shown for attentional control tasks, or reduced activity compared with young adults (N = 20). We used a modified stop-signal task involving coupled bimanual responses and manipulated whether both or just one hand was cued to stop. Stop-task difficulty was matched across groups. We found a group by condition interaction in supramarginal gyrus, anterior insula, rIFC, and preSMA, with activation increasing for successful Stop versus Go trials in the young adults only. Comparing the groups on Stop trials revealed preSMA and striatum hypoactivity for older adults. White matter tracts connecting rIFC, preSMA, and the subthalamic nuclei were associated with stronger activation of preSMA in older adults, suggesting that maintenance of the brain's structure has positive implications for brain function.

Withholding and canceling a response in ADHD adolescents.

BackgroundDeficient response inhibition in situations involving a trade-off between response execution and response stopping is a hallmark of attention deficit hyperactive disorder (ADHD). There are two key components of response inhibition; reactive inhibition where one attempts to cancel an ongoing response and prospective inhibition is when one withholds a response pending a signal to stop. Prospective inhibition comes into play prior to the presentation of the stop signal and reactive inhibition follows the presentation of a signal to stop a particular action. The aim of this study is to investigate the neural activity evoked by prospective and reactive inhibition in adolescents with and without ADHD.MethodsTwelve adolescents with ADHD and 12 age-matched healthy controls (age range 9–18) were imaged while performing the stop signal task (SST).ResultsReactive inhibition activated right inferior frontal gyrus (IFG) in both groups. ADHD subjects activated IFG bilaterally. In controls, prospective inhibition invoked preactivation of the same part of right IFG that activated during reactive inhibition. In ADHD subjects, prospective inhibition was associated with deactivation in this region. Controls also deactivated the medial prefrontal cortex (MPFC) during prospective inhibition, whereas ADHD subjects activated the same area.DiscussionThis pattern of activity changes in the same structures, but in opposite directions, was also evident across all phases of the task in various task-specific areas like the superior and middle temporal gyrus and other frontal areas.ConclusionDifferences between ADHD and control participants in task-specific and default mode structures (IFG and MPFC) were evident during prospective, but not during reactive inhibition.

Evidence for interaction between the stop signal and the Stroop task conflict.

Performance of the Stroop task reflects two conflicts--informational (between the incongruent word and ink color) and task (between relevant color naming and irrelevant word reading). The task conflict is usually not visible, and is only seen when task control is damaged. Using the stop-signal paradigm, a few studies demonstrated longer stop-signal reaction times for incongruent trials than for congruent trials. This indicates interaction between stopping and the informational conflict. Here we suggest that "zooming in" on task-control failure trials will reveal another interaction--between stopping and task conflict. To examine this suggestion, we combined stop-signal and Stroop tasks in the same experiment. When participants' control failed and erroneous responses to a stop signal occurred, a reverse facilitation emerged in the Stroop task (Experiment 1) and this was eliminated using methods that manipulated the emergence of the reverse facilitation (Experiment 2). Results from both experiments were replicated when all stimuli were used in the same task (Experiment 3). In erroneous response trials, only the task conflict increased, not the informational conflict. These results indicate that task conflict and stop-signal inhibition share a common control mechanism that is dissociable from the control mechanism activated by the informational conflict.

The Effects of 30Hz Theta Burst Transcranial Magnetic Stimulation (P01.171)

Objective: To examine the effects of 30Hz Theta Burst Transcranial Magnetic Stimulation (TBS) in healthy adults. Background The safety parameters of the Magstim SuperRapid2® limit the stimulation intensity of 50Hz TBS. By lowering the burst frequency to 30Hz, we are able to increase this limit, thus expanding the population that may participate in TBS research. Design/Methods: Seventeen right-handed healthy adults (32.5+/-9.3years; M:F=7:10) completed intermittent and continuous TBS (iTBS, cTBS) over the left motor cortex. TBS was performed with Magstim SuperRapid2® using published settings, except: 1) stimulation intensity was set higher, at 90% of Resting Motor Threshold (RMT), and 2) 30Hz, rather than 50Hz, burst frequency was used. Motor-Evoked Potentials (MEP) in the right first dorsal interosseous muscle were measured before, and one and 10 minutes after TBS. Before and 20 minutes after TBS, subjects also completed a stop-signal choice reaction time task consisting of choosing either X or O after a visual cue but stopping when a tone follows. The delay time for the tone is automatically adjusted to yield a ∼50% accuracy in the stop signal inhibition. Stop Signal Reaction Time (SSRT) is calculated by subtracting the Mean tone Delay (MD) from the Choice Reaction Time (CRT). We used repeated-measures ANOVA to compare MEPs and paired t-test to analyze stop-signal task measures. Results: 30Hz iTBS increased, while cTBS decreased MEP amplitudes with a significant Group*Time effect (p=0.009). After iTBS, CRT (p=0.006) and MD (p=0.010) increased. SSRT was not different (p=0.40). Reaction time measures did not change after cTBS. Conclusions: Similar to conventional (50Hz) TBS, 30Hz iTBS increases and cTBS decreases MEP amplitudes. Uniquely, 30Hz iTBS significantly changed responses on several stop signal reaction time measures. This technique, which can be used with higher intensities, merits further exploration in populations such as children who have higher RMTs. Supported by: 1. Tourette Syndrome Association (Steve Wu) 2. R01 MH081854 (Donald Gilbert). Disclosure: Dr. Gilbert has received personal compensation in an editorial capacity for Pediatrics Review and Education Program R11. Dr. Gilbert has received research support from Psyadon Pharmaceuticals and Otsuka Pharmaceuticals. Dr. Shahana has nothing to disclose. Dr. Huddleston has nothing to disclose. Dr. Wu has received research support from Psyadon Pharmaceuticals, Otsuka Pharmaceutical and Genzyme Corporation.

Special issue on impulsivity and compulsivity

This ‘Special issue on impulsivity and compulsivity’revisits a theme first explored by Psychopharmacology in1999 (146, 339–491). That issue of the journal focused onimpulsivity and represented somewhat of a landmark forthis topic in Psychopharmacology and perhaps for the fieldin general. It contained several now highly cited papers byseveral notable researchers in the field, including twoseminal theoretical reviews. One was by John Evenden(‘Varieties of impulsivity’ Evenden 1999) and has beencited 481 times at last count on the ISI Web of Knowledge.The other, on impulsivity, frontostriatal dysfunction anddrug abuse, was by David Jentsch and Jane Taylor (1999)and has been cited no fewer than 555 times.As Evenden’s review presciently anticipated, impulsivitycan be defined in several ways, reflecting what may be amultifaceted construct, engaging several distinct neuralsystems (Dalley et al. 2011). Most definitions emphasisethe tendency towards maladaptive premature behaviour, theloss of motor or response inhibition, the performance of‘automatic urges or impulses’, the tendency to avoid delayand rapidly discount the value of delayed rewards (‘impul-sive choice’) and the lack of reflection in making decisions,often of a highly ‘risky’ type. In general, advances inunderstanding of impulsivity have stemmed from advancesin its measurement in both humans and experimentalanimals, which may often proceed in parallel, usinganalogous tests such as the temporal discounting of rewardor stop signal inhibition. Many of these methods arerepresented in this special issue. Roige et al. provide adetailed and timely review of the considerable and excitingrecent work in mice (including genetic strains) on the samefive-choice serial reaction attentional task used by Dalley etal. to measure impulsivity in rats.Impulsivity refers to a constellation of traits that may befound in several neuropsychiatric disorders, includingattention deficit/hyperactivity disorder (ADHD), substanceabuse including alcoholism and cigarette smoking, mania,antisocial behaviour, as well as pathological aggression anddepression (i.e. suicide). There have been suggestions thatforms of impulsivity can be endophenotypes or intermedi-ate phenotypes for some disorders. For example, rats thatexhibit premature behaviour in the five-choice task appearto have a propensity for compulsive cocaine-seekingbehaviour, even before they are actually exposed to thedrug (Dalley et al. 2011). It is also possible that someabused drugs themselves may also cause impulsive behav-iours (Perry and Carroll 2008). Impulsive behaviour mayalso be especially important in the relapse to drug seeking,as they may share overlapping neural mechanisms (see inthis issue the study by Verdejo-Garcia et al.). Several formsof impulsivity are also prominent in ADHD, which oftenresponds to treatment with the indirect catecholamine

Neural processes of preparatory control for stop signal inhibition

This study investigated the preparatory control of motor inhibition and motor execution using a stop signal task (SST) and functional magnetic resonance imaging (fMRI). In the SST, a frequent "go" signal triggered a prepotent response and a less frequent "stop" signal prompted the inhibition of this response. Preparatory control of motor inhibition and execution in the stop signal trials were examined by contrasting brain activation between stop success and stop error trials during the fore-period, in which participants prepared to respond to go or to stop. Results from 91 healthy adults showed greater activation in the right prefrontal cortex and inferior parietal lobule during preparatory motor inhibition. Preparatory motor execution activated bilateral putamen, primary motor cortices, posterior cingulate cortex, ventromedial prefrontal cortex, and superior temporal/intraparietal sulci. Furthermore, the extents of these inhibition and execution activities were inversely correlated across subjects. On the basis of a median split of the stop signal reaction time (SSRT), subjects with short SSRT showed greater activity in the right orbital frontal cortex during preparatory inhibition. These new findings suggest that the go and stop processes interact prior to target presentation in the SST, in accord with recent computational models of stop signal inhibition.

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.

Overcoming the urge to splurge: Influencing eating behavior by manipulating inhibitory control

Background and objectivesWhen inhibitory control is lacking, people are more prone to indulge in high calorie food. This research examined whether increasing or decreasing inhibitory control influences food intake in opposite directions. MethodsIn this study, baseline inhibitory control ability was measured with the Stop Signal Task. Next, participants performed a modified Stop Signal Task with three within-subjects conditions: One type of high calorie food was always paired with a stop signal (inhibition manipulation), while another type of high calorie food was never presented with a stop signal (impulsivity manipulation). In the control condition, high calorie food was presented with a stop signal on half the trials. Following the manipulation, intake of the three food products that were used in the manipulation was measured during a taste test. ResultsParticipants with low inhibitory control abilities consumed more of the control food compared to participants with high inhibitory control abilities. However, the inhibition manipulation decreased food consumption in participants with low levels of inhibitory control to the same level of food intake as that of participants with high levels of inhibitory control. Conversely, the impulsivity manipulation increased food intake in participants with high levels of inhibitory control to the level of consumption of participants with low levels of inhibitory control. ConclusionsThese findings demonstrate the causal role of inhibition in eating behavior and suggest that strengthening inhibitory control can help people regain control over the consumption of high calorie food.

Decision Making and Response Inhibition as Predictors of Heavy Alcohol Use: A Prospective Study

Very few studies have investigated the "real world" prospective, predictive value of behavioral instruments used in laboratory studies to test decision-making abilities or impulse control. The current study examines the degree to which 2 commonly used decision-making/impulse control measures prospectively predict (heavy) alcohol use in a sample of college students. Two hundred healthy young adults (50% women) performed the Iowa Gambling Task (IGT) and a StopSignal inhibition task in the second college year. At testing and at the end of the fourth college year, heavy alcohol use was assessed. Disadvantageous performance on the IGT was associated with higher scores on a heavy drinking measure and higher quantity/frequency of alcohol use 2 years past neurocognitive testing in male students even after controlling for prior drinking. These results were corrected for heavy drinking and alcohol use in the period before neurocognitive testing. Interactions with gender indicated that this general pattern held for male but not for female students. Level of response inhibition was not associated with either of the alcohol use measures prospectively. These findings indicate that a neurocognitive decision-making task is predictive of maladaptive alcohol use. Advantageous decision makers appear to show adaptive real-life decision making, changing their drinking habits to the changing challenges of early adulthood (e.g., finishing college), whereas disadvantageous decision makers do not, and continue to drink heavily. These findings extend earlier findings of neurocognitive predictors of relapse in clinical substance-dependent groups, to subclinical alcohol use and abuse.

Neural mechanisms underlying stroop and stop-signal inhibition: modulation by susceptibility to prepotent interference from prior knowledge

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Methylphenidate But Not Atomoxetine or Citalopram Modulates Inhibitory Control and Response Time Variability

Response inhibition is a prototypical executive function of considerable clinical relevance to psychiatry. Nevertheless, our understanding of its pharmacological modulation remains incomplete. We used a randomized, double-blind, placebo-controlled, crossover design to examine the effect of an acute dose of methylphenidate (MPH) (30 mg), atomoxetine (ATM) (60 mg), citalopram (CIT) (30 mg), and placebo (PLAC) (dextrose) on the stop signal inhibition task in 24 healthy, right-handed men 18-35 years of age. Participants performed the task under each of the four drug conditions across four consecutive sessions. Methylphenidate led to a reduction in both response time variability and stop-signal reaction time (SSRT), indicating enhanced response inhibition compared with all other drug conditions. Crucially, the enhancement of response inhibition by MPH occurred without concomitant changes in overall response speed, arguing against a simple enhancement of processing speed. We found no significant differences between ATM and PLAC, CIT and PLAC, or ATM and CIT for either response time variability or SSRT. An acute dose of MPH but not ATM or CIT was able to improve SSRT and reduce response time variability in nonclinical participants. Improvements in response inhibition and response variability might underlie the reported clinical benefits of MPH in disorders such as attention-deficit/hyperactivity disorder.

Directed forgetting shares mechanisms with attentional withdrawal but not with stop-signal inhibition

To explore the mechanisms underlying the ability to intentionally forget, the present study combined an item-method directed forgetting paradigm with tasks that measure stop-signal inhibition (Experiments 1 and 2) and inhibition of return (IOR; Experiment 2). Following each study-phase instruction to remember (R) or forget (F), a target was presented centrally (Experiment 1) or to the left or right in the visual periphery (Experiment 2); the target required a speeded response that was sometimes countermanded by a central stop signal. Although stop-signal reaction times were unaffected by the preceding memory instruction (or relationship with word-target location), F instructions improved stopping and delayed responses. Replicating previous findings in the literature, significant IOR was observed following F instructions but not following R instructions (Experiment 2). These findings suggest that intentional forgetting is an active cognitive process that more likely engages attentional mechanisms related to orienting than those related to stop-signal inhibition.

Mechanisms and Dynamics of Cortical Motor Inhibition in the Stop-signal Paradigm: A TMS Study

The ability to stop ongoing motor responses in a split-second is a vital element of human cognitive control and flexibility that relies in large part on prefrontal cortex. We used the stop-signal paradigm to elucidate the engagement of primary motor cortex (M1) in inhibiting an ongoing voluntary motor response. The stop-signal paradigm taps the ability to flexibly countermand ongoing voluntary behavior upon presentation of a stop signal. We applied single-pulse TMS to M1 at several intervals following the stop signal to track the time course of excitability of the motor system related to generating and stopping a manual response. Electromyography recorded from the flexor pollicis brevis allowed quantification of the excitability of the corticospinal tract and the involvement of intracortical GABA(B)ergic circuits within M1, indexed respectively by the amplitude of the motor-evoked potential and the duration of the late part of the cortical silent period (SP). The results extend our knowledge of the neural basis of inhibitory control in three ways. First, the results revealed a dynamic interplay between response activation and stopping processes at M1 level during stop-signal inhibition of an ongoing response. Second, increased excitability of inhibitory interneurons that drives SP prolongation was evident as early as 134 msec following the instruction to stop. Third, this pattern was followed by a stop-related reduction of corticospinal excitability implemented around 180 after the stop signal. These findings point to the recruitment of GABA(B)ergic intracortical inhibitory circuits within M1 in stop-signal inhibition and support the notion of stopping as an active act of control.

Interactions between cognition and motivation during response inhibition

A growing number of studies have investigated how motivation interacts with particular cognitive functions, including attention, working memory, and other executive functions. In these studies, the emphasis has been on understanding how motivation impacts brain regions that contribute to improving behavioral performance. Less is understood about how positive incentives may actually impair behavioral performance. Here, we were interested in investigating a situation in which reward would be potentially deleterious to behavioral performance. Specifically, we hypothesized that rewarding participants for correct going would impair stopping performance. Critically, we hypothesized that the effects on inhibition would be specific, namely, not simply attributable to a speeding-up of reaction time during go trials. To investigate the interaction between inhibition and motivation, participants performed a stop-signal task during two conditions, namely, during a neutral, control condition and during a rewarded condition during which they were rewarded for correct go performance. Behaviorally, participants exhibited longer stop-signal reaction times during the reward relative to the control condition, indicating that it was harder to inhibit their responses during the former condition. Neuroimaging findings revealed that a host of brain regions were involved in stop-signal inhibition, as indexed via the contrast of successful and unsuccessful stop trials. Critically, a subset of these regions, which included the right inferior frontal gyrus, the left precentral gyrus, and bilateral putamen, exhibited significant inhibition by condition interactions, demonstrating that cognitive and motivational signals interact in the brain during inhibitory control.