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Inhibition is a key cognitive control mechanism humans use to enable goal-directed behavior. When rapidly exerted, inhibitory control has broad, nonselective motor effects, typically demonstrated using corticospinal excitability measurements (CSE) elicited by transcranial magnetic stimulation (TMS). For example, during rapid action-stopping, CSE is suppressed at both stopped and task-unrelated muscles. While such TMS-based CSE measurements have provided crucial insights into the fronto-basal ganglia circuitry underlying inhibitory control, they have several downsides. TMS is contraindicated in many populations (e.g., epilepsy or deep-brain stimulation patients), has limited temporal resolution, produces distracting auditory and haptic stimulation, is difficult to combine with other imaging methods, and necessitates expensive, immobile equipment. Here, we attempted to measure the nonselective motor effects of inhibitory control using a method unaffected by these shortcomings. Thirty male and female human participants exerted isometric force on a high-precision handheld force transducer while performing a foot-response stop-signal task. Indeed, when foot movements were successfully stopped, force output at the task-irrelevant hand was suppressed as well. Moreover, this nonselective reduction of isometric force was highly correlated with stop-signal performance and showed frequency dynamics similar to established inhibitory signatures typically found in neural and muscle recordings. Together, these findings demonstrate that isometric force recordings can reliably capture the nonselective effects of motor inhibition, opening the door to many applications that are hard or impossible to realize with TMS. [ABSTRACT FROM AUTHOR]

The nucleus accumbens (NAc) is thought to contribute to motivated behavior by signaling the value of reward-predicting cues and the delivery of anticipated reward. The NAc is subdivided into core and shell, with each region containing different populations of neurons that increase or decrease firing to rewarding events. While there are numerous theories of functions pertaining to these subregions and cell types, most are in the context of reward processing, with fewer considering that the NAc might serve functions related to action selection more generally. We recorded from single neurons in the NAc as rats of both sexes performed a STOP–change task that is commonly used to study motor control and impulsivity. In this task, rats respond quickly to a spatial cue on 80% of trials (GO) and must stop and redirect planned movement on 20% of trials (STOP). We found that the activity of reward-excited neurons signaled accurate response direction on GO, but not STOP, trials and that these neurons exhibited higher precue firing after correct trials. In contrast, reward-inhibited neurons significantly represented response direction on STOP trials at the time of the instrumental response. Finally, the proportion of reward-excited to reward-inhibited neurons and the strength of precue firing decreased as the electrode traversed the NAc. We conclude that reward-excited cells (more common in core) promote proactive action selection, while reward-inhibited cells (more common in shell) contribute to accurate responding on STOP trials that require reactive suppression and redirection of behavior. [ABSTRACT FROM AUTHOR]

Human frontocentral event-related potentials (FC-ERPs) are ubiquitous neural correlates of cognition and control, but their generating multiscale mechanisms remain mostly unknown. We used the Human Neocortical Neurosolver’s biophysical model of a canonical neocortical circuit under exogenous thalamic and cortical drive to simulate the cell and circuit mechanisms underpinning the P2, N2, and P3 features of the FC-ERP observed after Stop-Signals in the Stop–Signal task (SST; N = 234 humans, 137 female). We demonstrate that a sequence of simulated external thalamocortical and corticocortical drives can produce the FCERP, similar to what has been shown for primary sensory cortices. We used this model of the FC-ERP to examine likely circuit-mechanisms underlying FC-ERP features that distinguish between successful and failed action-stopping.We also tested their adherence to the predictions of the horse-race model of the SST, with specific hypotheses motivated by theoretical links between the P3 and Stop process. These simulations revealed that a difference in P3 onset between successful and failed Stops is most likely due to a later arrival of thalamocortical drive in failed Stops, rather than, for example, a difference in the effective strength of the input. In contrast, the same model predicted that early thalamocortical drives underpinning the P2 and N2 differed in both strength and timing across stopping accuracy conditions. Overall, this model generates novel testable predictions of the thalamocortical dynamics underlying FC-ERP generation during action-stopping. Moreover, it provides a detailed cellular and circuit-level interpretation that supports links between these macroscale signatures and predictions of the behavioral race model. [ABSTRACT FROM AUTHOR]

The ability to inhibit an already initiated response is crucial for navigating the environment. However, it is unclear which characteristics make stop-signals more likely to be processed efficiently. In three consecutive studies, we demonstrate that stop-signal modality and location are key factors that influence reactive response inhibition. Study 1 shows that tactile stop-signals lead to better performance compared to visual stop-signals in an otherwise visual choice-reaction task. Results of Study 2 reveal that the location of the stop-signal matters. Specifically, if a visual stop-signal is presented at a different location compared to the visual go-signal, then stopping performance is enhanced. Extending these results, study 3 suggests that tactile stop-signals and location-distinct visual stop-signals retain their performance enhancing effect when visual distractors are presented at the location of the go-signal. In sum, these results confirm that stop-signal modality and location influence reactive response inhibition, even in the face of concurrent distractors. Future research may extend and generalize these findings to other cross-modal setups. [ABSTRACT FROM AUTHOR]

Wan-Sen Yan,1,2 Meng-Meng Liu,1 Su-Jiao Liu1 1Department of Psychology, School of Medical Humanitarians, Guizhou Medical University, Guiyang, People’s Republic of China; 2Guizhou Research Institute for Health Development, Guizhou Medical University, Guiyang, People’s Republic of ChinaCorrespondence: Wan-Sen Yan, Department of Psychology, School of Medical Humanitarians, Guizhou Medical University, 9 Beijing Road, Yunyan District, Guiyang, 550004, People’s Republic of China, Tel +86-136-4850-4644, Email yanwansen@163.comBackground: Similar to addictive disorders, deficits on cognitive control might be involved in the onset and development of Binge Eating Disorder (BED). However, it remains unclear whether general or food-related inhibitory control impairments would be basically linked to overeating and binge eating behaviors. This study thus aimed to investigate behavioral performance and electrophysiological correlates of food-related inhibitory control among individuals with binge eating behavior.Methods: Sixty individuals with probable BED (pBED) and 60 well-matched healthy controls (HCs) were assessed using the typical Stop-Signal Task, a revised Go/No Go Task, and a food-related Go/No Go Task. Besides, another separate sample, including 35 individuals with pBED and 35 HCs, completed the food-related Go/No Go Task when EEG signals were recorded with the event-related potentials (ERPs).Results: The data revealed that the pBED group performed worse with a longer SSRT on the Stop-Signal Task compared with HCs (Cohen’s d = 0.58, p = 0.002). Moreover, on the food-related Go/No Go Task, the pBED group had a lower success rate of inhibition in no-go trials (Cohen’s d = 0.47, p = 0.012). The ERPs data showed that in comparison with HCs, the pBED group exhibited increased P300 latency (FC1, FC2, F3, F4, FZ) in the no-go trials of the food-related Go/No Go Task (Cohen’s d 0.56– 0.73, all p < 0.05).Conclusion: These findings suggested that individuals with binge eating could be impaired in both non-specific and food-related inhibitory control aspects, and the impairments in food-related inhibitory control might be linked to P300 abnormalities, implying a behavioral-neurobiological dysfunction mechanism implicated in BED.Keywords: binge eating disorder, inhibitory control, stop-signal, Go-No Go, ERPs

Flexible behavior requires restraint of actions that are no longer appropriate. This behavioral inhibition critically relies on frontal cortex - basal ganglia circuits. Within the basal ganglia, the globus pallidus pars externa (GPe) has been hypothesized to mediate selective proactive inhibition: being prepared to stop a specific action, if needed. Here we investigate population dynamics of rat GPe neurons during preparation-to-stop, stopping, and going. Rats selectively engaged proactive inhibition towards specific actions, as shown by slowed reaction times (RTs). Under proactive inhibition, GPe population activity occupied state-space locations farther from the trajectory followed during normal movement initiation. Furthermore, the state-space locations were predictive of distinct types of errors: failures-to-stop, failures-to-go, and incorrect choices. Slowed RTs on correct proactive trials reflected starting bias towards the alternative action, which was overcome before progressing towards action initiation. Our results demonstrate that rats can exert cognitive control via strategic adjustments to their GPe network state.

It is thought horses lack the prospection and brain architecture required for goal-directed, reflective model-based learning which considers future states. We investigate whether horses can use model-based strategy in an inhibitory task. Twenty subjects were trained for three sessions of a Stop-Signal paradigm using positive reinforcement (+R) for correct responding. All twenty failed to reach learning criterion. Subjects continued to touch in "Stop" contingencies indicating horses either: cannot complete Stop-Signal tasks; need further consolidation; or are utilising model-based cost-benefit analysis. Subjects underwent a further three sessions with the addition of negative punishment (+R/-P) as a cost for errors of emission (EE). If horses lack the ability to complete Stop-Signal tasks, EE would remain high across both treatments. If horses found Stop-Signal difficult but the introduction of cost aided their learning, EE would gradually decrease throughout the +R/-P condition. If horses built a cognitive model of the task but developed a strategy of indiscriminate responding in the +R condition, EE would suddenly decrease with the introduction of cost. A significant, immediate reduction in EE was observed when cost was introduced (p=0.02) that remained stable throughout the +R/-P condition providing evidence consistent with model-based cost-benefit analysis in horses. • Model-based learning investigated in horses during a Stop-Signal inhibitory control task. • Horses trained to inhibit touch response to a target when a light cue was present, using positive reinforcement (+R). • Horses responded indiscriminately to stimuli during initial 3 sessions of Stop-Signal. • A further 3 sessions with positive reinforcement plus negative punishment (+R/-P). • Immediate reduction in errors was observed (p=0.02), providing evidence consistent with model-based cost-benefit analysis in horses. [ABSTRACT FROM AUTHOR]

ABSTRACT: During human motor control, the three pathways of motor control coordinate to complete human response and inhibition control, so whether different types of motor skills training will affect the three pathways of motor control is the main question in this study. Magnetic resonance imaging was combined with behavioural evaluation to analyse the effects of different special training sessions on the motor control network of the frontal lobe and basal ganglia and to explore the role of the central nervous system in the regulation of motor behaviour. A Stop-signal paradigm was used to measure reaction and inhibition capacity, functional magnetic resonance imaging was used for whole brain scanning, and resting state data were collected. Compared to the control group, the competitive aerobics athletes had better reflexes while the soccer players had both better reflexes and inhibitory control. Furthermore, we found that training in the two sets of skills resulted in significant differences in different resting state brain function parameters compared with the control group. Additionally, there were significant differences among the three groups in the direct and indirect pathways of motor control in terms of functional connectivity. Open skill training may improve reaction ability while closed skill training improve both reaction and inhibition ability. These results suggest that the strength of the functional connectivity between the right inferior frontal gyrus and the left putamen may be a key to improving the inhibitory, and the left supplementary motor area- bilateral thalamic loop may play an inhibitory role in motor control.

Historically, the orbitofrontal cortex (OFC) has been implicated in a variety of behaviors ranging from reversal learning and inhibitory control to more complex representations of reward value and task space. While modern interpretations of the OFC's function have focused on a role in outcome evaluation, these cognitive processes often require an organism to inhibit a maladaptive response or strategy. Single-unit recordings from the OFC in rats performing a stop-change task show that the OFC responds strongly to STOP trials. To investigate the role that the OFC plays in stop-change performance, we expressed halorhodopsin (eNpHR3.0) in excitatory neurons in the OFC and tested rats on the stop-change task. Previous work suggests that the OFC differentiates between STOP trials based on trial sequence (i.e., gS trials: STOP trials preceded by a GO vs sS trials: STOP trials preceded by a STOP). We found that yellow light activation of the eNpHR3.0-expressing neurons significantly decreased accuracy only on STOP trials that followed GO trials (gS trials). Further, optogenetic inhibition of the OFC speeded reaction times on error trials. This suggests that the OFC plays a role in inhibitory control processes and that this role needs to be accounted for in modern interpretations of OFC function., Competing Interests: The authors declare no competing financial interests., (Copyright © 2024 Brockett et al.)

Flexible behavior requires restraint of actions that are no longer appropriate. This behavioral inhibition critically relies on frontal cortex - basal ganglia circuits. Within the basal ganglia, the globus pallidus pars externa (GPe) has been hypothesized to mediate selective proactive inhibition: being prepared to stop a specific action, if needed. Here we investigate population dynamics of rat GPe neurons during preparation-to-stop, stopping, and going. Rats selectively engaged proactive inhibition towards specific actions, as shown by slowed reaction times (RTs). Under proactive inhibition, GPe population activity occupied state-space locations farther from the trajectory followed during normal movement initiation. Furthermore, the state-space locations were predictive of distinct types of errors: failures-to-stop, failures-to-go, and incorrect choices. Slowed RTs on correct proactive trials reflected starting bias towards the alternative action, which was overcome before progressing towards action initiation. Our results demonstrate that rats can exert cognitive control via strategic adjustments to their GPe network state.

The honey bee stop-signal may decrease recruitment by causing waggle dancers to cease dancing when food patch conditions deteriorate. However, little is known about how signaling may change during the time a signaler is inside the nest and what triggers signal production. All previous feeder studies have used crowded feeders to stimulate stop-signal production. We focused on individual foragers and found that bees returning from uncrowded feeders also produced stop-signals. The number of signals produced by these foragers was roughly proportional to the duration of their stay in the nest. Foragers significantly decreased the rate of signal production throughout their nest stay, potentially reflecting a decrease in signaling motivation with increased time inside the nest. There is a slight trend for signal pulse duration to increase and fundamental frequency to decrease throughout a signaler's nest stay. We examined the effect of crowded feeder conditions by training 20 foragers to a feeder and following focal forager behavior before and after reducing the number of feeding spots. This manipulation increased feeding wait time from 0 s to 409.4±264.3 s without significantly increasing colony nectar intake. Our treatment did not change signal production by focal foragers but significantly doubled the number of stop-signals that focal foragers received inside the nest. At least 38% of these received signals came from foragers visiting the same feeder. Thus, the colony produces stop-signals at a baseline level that can be elevated in response to crowded foraging conditions. © INRA/DIB-AGIB/EDP Sciences, 2009.

Response inhibition is thought to improve throughout childhood and into adulthood. Despite the relationship between age and the ability to stop ongoing behavior, questions remain regarding whether these age-related changes reflect improvements in response inhibition or in other factors that contribute to response performance variability. Functional neuroimaging data shows age-related changes in neural activity during response inhibition. While traditional methods of exploring neuroimaging data are limited to determining correlational relationships, newer methods can determine predictability and can begin to answer these questions. Therefore, the goal of the current study was to determine which aspects of neural function predict individual differences in age, inhibitory function, response speed, and response time variability. We administered a stop-signal task requiring rapid inhibition of ongoing motor responses to healthy participants aged 9-30. We conducted a standard analysis using GLM and a predictive analysis using high-dimensional regression methods. During successful response inhibition we found regions typically involved in motor control, such as the ACC and striatum, that were correlated with either age, response inhibition (as indexed by stop-signal reaction time; SSRT), response speed, or response time variability. However, when examining which variables neural data could predict, we found that age and SSRT, but not speed or variability of response execution, were predicted by neural activity during successful response inhibition. This predictive relationship provides novel evidence that developmental differences and individual differences in response inhibition are related specifically to inhibitory processes. More generally, this study demonstrates a new approach to identifying the neurocognitive bases of individual differences.

Restrained eaters constantly limit their eating behavior to avoid gaining weight. Previous research suggests that fundamental deficits in response inhibition might play a role in the development of disinhibited eating among restrained eaters. The current study focuses on the impact of food vs. non-food stimuli on response inhibition in high vs. low restrained eaters. Seventy-five females (38 high and 37 low restrained eaters) completed a novel food stop-signal task in which they were required to discriminate between food and non-food images while inhibiting their response when a stop-signal appeared. The ability to inhibit a response was assessed separately for food and non-food trials, which were used to assess specific inhibition to food and general inhibitory abilities, respectively. Overall, high restrained eaters exhibited poorer response inhibition to non-food stimuli compared to low restrained eaters. Most importantly, high restrained eaters were better able to inhibit a response following presentation of food compared to non-food stimuli. In contrast, low restrained eaters were better at inhibiting a response following non-food compared to food stimuli. We suggest that this pattern is due to fast and strong activation of the response inhibition system in high restrained eaters when facing food stimuli - an activation which might later lead to a paradoxical breakdown of control over eating behavior. [ABSTRACT FROM AUTHOR]

Parental investment theory suggests that women, due to greater investment in child rearing, can be more choosy than men when considering a potential mate. A corollary to this is that women should possess greater inhibition abilities compared to men in contexts related to sex and reproduction. This notion has found support from the inhibition literature demonstrating that while women do indeed show greater inhibition on tasks that include a social aspect, no such effect is found on cognitive tasks that do not possess a social component. In the present experiment, participants (N = 66) performed a variant of a classic Go/No-Go task consisting of infrequent No-Go trials in which a response needed to be withheld. Importantly, the stimuli were geometric shapes possessing no social component. Results showed that women outperformed men on the No-Go trials, indicating greater inhibition. No significant difference was found in reaction time on Go trials. Thus, the results cannot be explained in terms of a speed/accuracy trade-off. We discuss the findings in the context of the female-evolved inhibition hypothesis. [ABSTRACT FROM AUTHOR]

Several brain regions and connectivity networks may be altered as aging occurs. We are interested in investigating if resting-state functional magnetic resonance imaging (RS-fMRI) can also be valid as an indicator of individual differences in association with inhibition performance among aged (including middle-aged) people. Seventy-two healthy adults (40–77 years of age) were recruited. Their RS-fMRI images were acquired and analyzed via two cluster-analysis methods: local synchronization of spontaneous brain activity measured by regional homogeneity (ReHo) and fractional amplitude of low-frequency fluctuations (fALFF) of blood oxygenation level-dependent signals. After the RS-fMRI acquisition, participants were instructed to perform a stop-signal task, in which the stop signal reaction time (SSRT) was calculated based on the horse-race model. Among participants, the ReHo/fALFF and SSRT were correlated with and without partialling-out the effect of age. The results of this study showed that, although aging may alter brain networks, the spontaneous activity of the age-related brain networks can still serve as an effective indicator of individual differences in association with inhibitory performance in healthy middle-aged and elderly people. This is the first study to use both ReHo and fALFF on the same dataset for conjunction analyses showing the relationship between stopping performance and RS-fMRI in the elderly population. The relationship may have practical clinical applications. Based on the overall results, the current study demonstrated that the bilateral inferior frontal gyrus and parts of the default mode network activation were negatively correlated with SSRT, suggesting that they have crucial roles in inhibitory function. However, the pre-supplementary motor area (pre-SMA) and SMA played only a small role during the resting state in association with stopping performance.

Retrieving information from episodic memory may result in later inaccessibility of related but task-irrelevant information. This phenomenon, known as retrieval-induced forgetting, is thought to represent a specific instance of broader cognitive control mechanisms, that would come into play during memory retrieval, whenever non-target competing memories interfere with recall of target items. Recent neuroimaging studies have shown an association between these mechanisms and the activity of the right Prefrontal Cortex. However, so far, few studies have attempted at establishing a causal relationship between this brain region and behavioural measures of cognitive control over memory. To address this missing link, we delivered transcranial Direct Current Stimulation (tDCS) over the right Inferior Frontal Gyrus (rIFG) during a standard retrieval-practice paradigm with category-exemplar word pairs. Across two experiments, tDCS abolished retrieval-induced forgetting to different degrees, compared to the sham control group whereas no effects of stimulation emerged in an ancillary measure of motor stopping ability. Moreover, influence analyses on specific subsets of the experimental material revealed diverging patterns of results, which depended upon the different categories employed in the retrieval-practice paradigm. Overall, the results support the view that rIFG has a causal role in the control of interference in memory retrieval and highlight the often underestimated role of stimulus material in affecting the effects. The present findings are therefore relevant in enriching our knowledge about memory functions from both a theoretical and methodological perspective. [ABSTRACT FROM AUTHOR]

Background: Disinhibition is apparent in users of many substances, including heavy drinkers. Previous research has shown that brief training to improve inhibitory control is associated with reduced alcohol consumption. We investigated whether a new form of inhibitory training would produce greater reductions, relative to a carefully designed control condition and a proven method of reducing consumption, the Brief Alcohol Intervention (BAI).Methods: One hundred and fourteen regular drinkers were assigned randomly to one of five training conditions: Control (no inhibitory training); Beer-NoGo (inhibit responses linked to task-irrelevant pictures of beer); Restrained-Stop (requiring more urgent inhibition but without pictures of beer); Combined (a previously untested form of training requiring urgent inhibition to pictures of beer); or BAI. The outcome measures were alcohol consumption in the week before and after training, and in a bogus taste test administered immediately post-training.Results: Participation in the study, regardless of condition, was associated with reductions in weekly consumption. However, only the BAI produced a greater reduction relative to the Control condition. The training tasks were not associated with reductions in taste test consumption.Conclusions: Although concerns about low power limit confidence, the current study suggests that three forms of inhibitory training do not have a substantial effect on drinking beyond the effect of simple assessment, in comparison to a control task which does not promote impulsive responding. Future research needs to establish a training protocol that produces greater reductions in consumption not only relative to the effect of assessment but also relative to a BAI. [ABSTRACT FROM AUTHOR]

Increasing a participant's ability to prepare for response inhibition is known to result in longer Go response times and is thought to engage a 'top-down fronto-striatal inhibitory task set.' This premise is supported by the observation of anterior striatum activation in functional magnetic resonance imaging (fMRI) analyses that focus on uncertain versus certain Go trials. It is assumed that setting up a proactive inhibitory task set also influences how participants subsequently implement stopping. To assess this assumption, we aimed to manipulate the degree of proactive inhibition in a modified stop-signal task to see how this manipulation influences activation when reacting to the Stop cue. Specifically, we tested whether there is differential activity of basal ganglia nuclei, namely the subthalamic nucleus (STN) and anterior striatum, on Stop trials when stop-signal probability was relatively low (20%) or high (40%). Successful stopping was associated with increased STN activity when Stop trials were infrequent and increased caudate head activation when Stop trials were more likely, suggesting a different implementation of reactive response inhibition by the basal ganglia for differing degrees of proactive response control. Hum Brain Mapp 37:4706-4717, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Humans and non-human primates are known to lengthen their response time (RT) to a go signal when they occasionally must cancel their responses following a stop signal in a countermanding task as well as to adjust their RT adaptively on a trial-by-trial basis. Less is clear regarding the adaptive RT adjustments in the countermanding performance of rodents. To investigate this question, male Wistar rats ( N = 12) were trained with food reward to press a lever directly below an illuminated light (go signal), but to countermand the lever press subsequent to a tone (stop signal) presented infrequently (25% of trials) at variable delays. Rats were then tested in a standard responding task (0% stop trials) or a countermanding task with a 10-s or 1-s TO interval following errors. Rats exhibited significant RT lengthening in the countermanding task, compared with the standard responding task, and RT shortening following consecutive correct go trials. They also show RT lengthening following both error trials in the standard responding task and unrewarded, non-canceled stop trials in the countermanding task. RT lengthening following erroneous stop trials was observed in sessions with a 10-s TO interval, but not with a 1-s TO interval. Analyses of RT distributions suggest that RT lengthening results largely from reduced sensitivity to the go signal, but also from reduced readiness. These findings indicate that rats exert control in the countermanding task by lengthening RT in anticipation of stop trials to avoid long, unrewarded TO intervals. [ABSTRACT FROM AUTHOR]

• fNIRS described brain activities during a Stroop-matching/stop-signal task. • Different inhibitory types showed distinct patterns of brain activation. • Interference control demands activated frontal and temporoparietal regions. • Inhibition and interruption of responses activated different frontal regions. • The dimensional approach of ADHD was related to differences in frontal activities. Attention deficit hyperactivity disorder (ADHD) is associated with deficits in inhibitory functions including interference control, inhibition of prepotent/automatic responses and suppression of already initiated responses. This study used functional near-infrared spectroscopy (fNIRS) to investigate the neural basis of these three forms of inhibition assessed by a recently developed behavioral protocol combining the Stroop-matching/stop-signal task in twenty-five young adults with inattention, impulsivity and/or hyperactivity symptoms. The severity of ADHD symptoms was measured using the Adult ADHD Self-Report Scale (ASRS). The concentration of oxygenated hemoglobin (HbO) was assessed in the dorsolateral prefrontal cortex (DLPFC), inferior frontal gyrus (IFG) and temporoparietal regions (TP) during the Stroop-matching/stop-signal task. Correlations yielded significant associations between ASRS scores and HbO concentration in frontal regions during blocks with stop-signal tasks, namely the right IFG, the left DLPFC and the left IFG. This study revealed that different types of inhibition involve unique frontal and temporoparietal activities and linked frontal dysfunction during the suppression of ongoing responses to the severity of ADHD symptoms. [ABSTRACT FROM AUTHOR]

There is evidence to suggest that impulsivity is predicted by socioeconomic background, with people from more deprived backgrounds tending to be more impulsive, and by current mood, with poorer mood associated with greater impulsivity. However, impulsivity is not a unitary construct, and previous research in this area has focused on measures of ‘waiting’ impulsivity rather than behavioural disinhibition. We administered a standard measure of behavioural disinhibition, the stop-signal task, to 58 adult participants from a community sample. We had measured socioeconomic background using participant postcode at age 16, and assigned participants to receive either a neutral or a negative mood induction. We found no effects of mood on behavioural disinhibition, but we found a significant effect of socioeconomic background. Participants who had lived in more deprived postcodes at age 16 showed longer stop-signal reaction times, and hence greater behavioural disinhibition. The pattern was independent of participant age and overall reaction time. Though caution is required inferring causality from correlation, it is possible that that experiencing socioeconomic deprivation in childhood and adolescence may lead to greater behavioural disinhibition in adulthood.

Being able to stop (or inhibit) an action rapidly as in a stop-signal task is an essential human ability. Previous studies showed that when a pre-stimulus cue warned of the possible need to stop a response in an upcoming trial, participants’ response time (RT) increased if the subsequent trial required a go response (i.e., go RT cost) relative to a trial where this uncertainty was not present. This increase of the go RT correlated with more efficient response stopping. However, it remains a question whether foreknowledge of upcoming inhibition trials given prior to the task is sufficient to modulate neural activity associated with the primary go responses irrespective of whether stopping an overt response is required. We presented three task conditions with identical primary (i.e., go) response trials but without pre-stimulus cues. Participants were informed that Condition 1 had only go trials (All-go condition), Condition 2 required a stop response for some trials (Stop condition), and Condition 3 required a response incongruent with the primary response (i.e., Switch response) for some trials (Switch condition). Participants performed the tasks during functional magnetic resonance imaging (fMRI) scans. Results showed a significant increase in the go RT (cost) in the Stop and Switch conditions relative to the All-go condition. The go RT cost was correlated with decreased inhibition time. fMRI activation in the frontal-basal-ganglia regions during the go responses in the Stop and Switch conditions was also correlated with the efficiency of Stop and Switch responses. These results suggest that foreknowledge prior to the task is sufficient to influence neural activity associated with the primary response and modulate inhibition efficiency, irrespective of whether stopping an overt response is required.

Inhibitory control is an important component of executive function. An emerging literature in humans suggests that inhibitory control is sexually dimorphic and modulated by sex steroids, but evidence for such a link in nonhuman animals is scarce. In this study, we examined the effects of menstrual cycle and biological sex on response inhibition, as measured by a Stop-Signal task, in the baboon ( Papio papio ). The monkeys (n = 13) were socially-housed, with voluntary access to multiple touchscreen computerized stations. The task required monkeys to inhibit prepotent responses (touching a target, “Go” trials) following the appearance of a visual stop signal on 25% of the trials (“Stop” trials). The cognitive data, consisting of computerized records of the monkeys’ performance on the Stop-Signal task over a year of testing, were matched to records of female sexual swellings. Same-day menstrual and cognitive data were available for 5 females, aged 5–18 years. These data were compared to those of 8 males (5–14 years old) performing the Stop-Signal task over the same time period. Contrary to our hypothesis, performance on the task was not significantly affected by the phase (ovulatory vs. luteal) of the cycle in females. However, males were slower than females on Go trials and were less efficient in inhibiting responses on Stop trials. Slower responses in males were indicative of a speed-accuracy trade-off, as overall accuracy was also better in males than in females. Analyses of trial history indicated that males did not speed as much as females following a successful Go trial, but did not differ from females in post-error slowing or post-inhibiting responses. Overall, the data show that biological sex modulates Stop-Signal performance in the baboon, with males exhibiting slower response execution overall, less efficient inhibition, but greater accuracy than females. This pattern of sex differences may reflect motivational sex differences in which males emphasize accuracy rather than speed. Interestingly, these sex differences do not seem to vary as a function of ovarian hormones in females. Males’ greater focus on accuracy is possibly due to enhanced sensitivity to reward mediated by testosterone levels. [ABSTRACT FROM AUTHOR]

Previous work using transcranial magnetic stimulation (TMS) demonstrated that the right presupplementary motor area (preSMA), a node in the fronto-basal-ganglia network, is critical for response inhibition. However, TMS influences interconnected regions, raising the possibility of a link between the preSMA activity and the functional connectivity within the network. To understand this relationship, we applied single-pulse TMS to the right preSMA during functional magnetic resonance imaging when the subjects were at rest to examine changes in neural activity and functional connectivity within the network in relation to the efficiency of response inhibition evaluated with a stop-signal task. The results showed that preSMA-TMS increased activation in the right inferior-frontal cortex (rIFC) and basal ganglia and modulated their task-free functional connectivity. Both the TMS-induced changes in the basal-ganglia activation and the functional connectivity between rIFC and left striatum, and of the overall network correlated with the efficiency of response inhibition and with the white-matter microstructure along the preSMA-rIFC pathway. These results suggest that the task-free functional and structural connectivity between the rIFCop and basal ganglia are critical to the efficiency of response inhibition. Hum Brain Mapp 37:3236-3249, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objectives: Inhibitory control training has been hypothesised as a technique that will improve an individual's ability to overrule impulsive reactions in order to regulate behaviour consistent with long-term goals.Methods: A meta-analysis of 19 studies of inhibitory control training and health behaviours was conducted to determine the effect of inhibitory control training on reducing harmful behaviours. Theoretically driven moderation analyses were also conducted to determine whether extraneous variables account for heterogeneity in the effect; in order to facilitate the development of effective intervention strategies. Moderators included type of training task, behaviour targeted, measurement of behaviour and training duration.Results: A small but homogeneous effect of training on behaviour was found,d+  = 0.378, CI95 = [0.258, 0.498]. Moderation analyses revealed that the training paradigm adopted, and measurement type influenced the size of the effect such that larger effects were found for studies that employed go/no-go (GNG) training paradigms rather than stop-signal task paradigms, and objective outcome measures that were administered immediately yielded the largest and most consistent effects on behaviour.Conclusions: Results suggest that GNG inhibitory control training paradigms can influence health behaviour, but perhaps only in the short-term. Future research is required to systematically examine the influence of training duration, and the longevity of the training effect. Determining these factors could provide the basis for cost-effective and efficacious health-promoting interventions. [ABSTRACT FROM PUBLISHER]

Summary The suppression of inappropriate actions is critical for flexible behavior. Cortical-basal ganglia networks provide key gating mechanisms for action suppression, yet the specific roles of neuronal subpopulations are poorly understood. Here, we examine Arkypallidal (“Arky”) and Prototypical (“Proto”) globus pallidus neurons during a Stop task, which requires abrupt cancellation of an imminent action. We first establish that Arky neurons can be identified by their firing properties across the natural sleep/wake cycle. We then show that Stop responses are earlier and stronger in the Arky compared to the Proto subpopulation. In contrast to other basal ganglia neurons, pallidal Stop responses are selective to Stop, rather than Go, cues. Furthermore, the timing of these Stop responses matches the suppression of developing striatal Go-related activity. Our results support a two-step model of action suppression: actions-in-preparation are first paused via a subthalamic-nigral pathway, then cancelled via Arky GABAergic projections to striatum. [ABSTRACT FROM AUTHOR]

Disruptions to inhibitory control are believed to contribute to multiple aspects of drug abuse, from preexisting vulnerability in at-risk individuals, through escalation to dependence, to promotion of relapse in chronic users. Paradigms investigating the suppression of actions have been investigated in animal and human research on drug addiction. Rodent research has focused largely on impulsive behaviors, often gauged by premature responding, as a viable model highlighting the relevant role of dopamine and other neurotransmitters primarily in the striatum. Human research on action inhibition in stimulant dependence has highlighted impaired performance and largely prefrontal cortical abnormalities as part of a broader pattern of cognitive abnormalities. Animal and human research implicate inhibitory difficulties mediated by fronto-striatal circuitry both preceding and as a result of excessive stimulus use. In this regard, response-inhibition has proven a useful cognitive function to gauge the integrity of fronto-striatal systems and their role in contributing to impulsive and compulsive features of drug dependence. This article is part of a Special Issue entitled SI:Addiction circuits . [ABSTRACT FROM AUTHOR]

The ability to inhibit or adapt unwanted actions or movements is a critical feature of almost all forms of behavior. Many have attributed this ability to frontal brain areas such as the anterior cingulate cortex (ACC) and the medial prefrontal cortex (mPFC), but the exact contribution of each brain region is often debated because their functions are not examined in animals performing the same task. Recently, we have shown that ACC signals a need for cognitive control and is crucial for the adaptation of action selection signals in dorsomedial striatum (DMS) in rats performing a stop-change task. Here, we show that unlike ACC, the prelimbic region of mPFC does not disrupt the inhibition or adaption of an action plan at either the level of behavior or downstream firing in DMS. Instead, lesions to mPFC correlate with changes in DMS signals involved in action initiation and disrupt performance on GO trials while improving performance on STOP trials. • Medial prefrontal cortex (mPFC) lesions alter stop-signal performance • mPFC lesioned rats perform better on STOP trials but worse on GO trials • Directional firing in dorsomedial striatum (DMS) is altered in mPFC lesioned rats Here, Brockett et al. show that lesions to medial prefrontal cortex (mPFC) disrupt action initiation but not the inhibition or adaptation of action plans on a variant of the stop-signal task. Moreover, Brockett et al. show that lesions to mPFC alter directional signaling in dorsomedial striatum. [ABSTRACT FROM AUTHOR]

Inhibitory control training has been shown to influence eating behaviour in the laboratory; however, the reliability of these effects is not yet established outside the laboratory, nor are the mechanisms responsible for change in behaviour. Two online Stop-Signal Task training interventions were conducted to address these points. In Study 1, 72 participants completed baseline and follow-up measures of inhibitory control, self-regulatory depletion, fat intake and body-mass index. Participants were randomly assigned to complete one of three Stop-Signal Tasks daily for ten days: food-specific inhibition – inhibition in response to unhealthy food stimuli only, general inhibition – inhibition was not contingent on type of stimuli, and control – no inhibition. While fat intake did not decrease, body-mass index decreased in the food-specific condition and change in this outcome was mediated by changes in vulnerability to depletion. In Study 2, the reliability and longevity of these effects were tested by replicating the intervention with a third measurement time-point. Seventy participants completed baseline, post-intervention and follow-up measures. While inhibitory control and vulnerability to depletion improved in both training conditions post-intervention, eating behaviour and body-mass index did not. Further, improvements in self-regulatory outcomes were not maintained at follow-up. It appears that while the training paradigm employed in the current studies may improve self-regulatory outcomes, it may not necessarily improve health outcomes. It is suggested that this may be due to the task parameters, and that a training paradigm that utilises a higher proportion of stop-signals may be necessary to change behaviour. In addition, improvements in self-regulation do not appear to persist over time. These findings further current conceptualisations of the nature of self-regulation and have implications for the efficacy of online interventions designed to improve eating behaviour. [ABSTRACT FROM AUTHOR]

Background : Cognitive control impairments are linked to functional outcome in schizophrenia. The goal of the current study was to investigate precise abnormalities in two aspects of cognitive control: reactively changing a prepared response, and monitoring performance and adjusting behavior accordingly. We adapted an oculomotor task from neurophysiological studies of the cellular basis of cognitive control in nonhuman primates. Methods : 16 medicated outpatients with schizophrenia (SZ) and 18 demographically-matched healthy controls performed the modified double-step task. In this task, participants were required to make a saccade to a visual target. Infrequently, the target jumped to a new location and participants were instructed to rapidly inhibit and change their response. A race model provided an estimate of the time needed to cancel a planned movement. Response monitoring was assessed by measuring reaction time (RT) adjustments based on trial history. Results : SZ patients had normal visually-guided saccadic RTs but required more time to switch the response to the new target location. Additionally, the estimated latency of inhibition was longer in patients and related to employment. Finally, although both groups slowed down on trials that required inhibiting and changing a response, patients showed exaggerated performance-based adjustments in RTs, which was correlated with positive symptom severity. Conclusions : SZ patients have impairments in rapidly inhibiting eye movements and show idiosyncratic response monitoring. These results are consistent with functional abnormalities in a network involving cortical oculomotor regions, the superior colliculus, and basal ganglia, as described in neurophysiological studies of non-human primates using an identical paradigm, and provide a translational bridge for understanding cognitive symptoms of SZ. [ABSTRACT FROM AUTHOR]

Background Although the majority of substance use disorders depict reliable deficits in inhibitory control (IC), similar deficits are not consistently found in nicotine dependence. The mixed results of past research may have been due to confounding variables known to independently influence IC function, including age, concurrent drug use and particularly, length of nicotine abstinence. Methods A stop signal task was used to examine stop signal reaction time (SSRT), a typical measure of IC, in nicotine dependence across two studies that attempted to closely control for IC confounds. Study 1 compared the SSRT of 37 dependent cigarette smokers (11 females) to 36 non-smokers (13 females), following 3-h of nicotine abstinence. Study 2 compared 22 dependent cigarette smokers’ (11 females) SSRT scores when satiated on nicotine to their performance following 10-h of nicotine abstinence. Results Nicotine dependent individuals did not differ from controls in SSRT performance following 3-h abstinence, but showed a significant decline in performance following 10-h abstinence, when compared to nicotine satiation. Conclusions During shorter abstinence periods, the acute benefits of nicotine satiation appear to facilitate inhibitory control; however, IC was poorer during extended periods of nicotine abstinence. In turn, this suggests that the reliability of IC dysfunction in nicotine dependence varies according to abstinence length and needs to be carefully considered for future behavioural and neuroimaging examination of IC within this population. [ABSTRACT FROM AUTHOR]

Response inhibition is an important act of control in many domains of psychology and neuroscience. It is often studied in a stop-signal task that requires subjects to inhibit an ongoing action in response to a stop signal. Performance in the stop-signal task is understood as a race between a go process that underlies the action and a stop process that inhibits the action. Responses are inhibited if the stop process finishes before the go process. The finishing time of the stop process is not directly observable; a mathematical model is required to estimate its duration. Logan and Cowan (1984) developed an independent race model that is widely used for this purpose. We present a general race model that extends the independent race model to account for the role of choice in go and stop processes, and a special race model that assumes each runner is a stochastic accumulator governed by a diffusion process. We apply the models to 2 data sets to test assumptions about selective influence of capacity limitations on drift rates and strategies on thresholds, which are largely confirmed. The model provides estimates of distributions of stop-signal response times, which previous models could not estimate. We discuss implications of viewing cognitive control as the result of a repertoire of acts of control tailored to different tasks and situations. [ABSTRACT FROM AUTHOR]

The midcingulate cortex (MCC; often somewhat imprecisely referred to as dorsal or cognitive part of the anterior cingulate cortex or dACC) is a core region contributing to cognitive control. Neuroanatomical deviations in the midcingulate region have been observed in a variety of mental disorders. Even in healthy subjects a high degree of morphological variability is seen, for example concerning the degree of anterior midcingulate fissurization. To investigate the relationship between anterior midcingulate morphology and function, individuals with a leftward midcingulate folding asymmetry (LEFT) were compared to individuals showing a lower degree of fissurization or a rightward asymmetric folding (REST). Data from two experiments, a masked Stroop paradigm and a combined go/no-go and stop-signal task, are reported. With the masked Stroop task, LEFT subjects revealed a better processing of incongruent Stroop stimuli when compared to REST subjects. This was reflected in both augmented N400 responses as well as significantly higher accuracy scores. In addition, similar effects were found with event-related potentials from the combined go/no-go and stop-signal task. Here, the N200 but not the P300, which have been associated with conflict-related and evaluative processing stages, respectively, was found to be significantly increased with LEFT subjects. The results of this study foster an association of midcingulate fissurization with differences in behavior and neurophysiological functioning related to cognitive control. [ABSTRACT FROM AUTHOR]

The ability to inhibit action is critical for everyday behavior and is affected by a variety of disorders. Behavioral control and response inhibition is thought to depend on a neural circuit that includes the dorsal striatum, yet the neural signals that lead to response inhibition and its failure are unclear. To address this issue, we recorded from neurons in rat dorsomedial striatum (mDS) in a novel task in which rats responded to a spatial cue that signaled that reward would be delivered either to the left or to the right. On 80% of trials rats were instructed to respond in the direction cued by the light (GO). On 20% of trials a second light illuminated instructing the rat to refrain from making the cued movement and move in the opposite direction (STOP). Many neurons in mDS encoded direction, firing more or less strongly for GO movements made ipsilateral or contralateral to the recording electrode. Neurons that fired more strongly for contralateral GO responses were more active when rats were faster, showed reduced activity on STOP trials, and miscoded direction on errors, suggesting that when these neurons were overly active, response inhibition failed. Neurons that decreased firing for contralateral movement were excited during trials in which the rat was required to stop the ipsilateral movement. For these neurons activity was reduced when errors were made and was negatively correlated with movement time suggesting that when these neurons were less active on STOP trials, response inhibition failed. Finally, the activity of a significant number of neurons represented a global inhibitory signal, firing more strongly during response inhibition regardless of response direction. Breakdown by cell type suggests that putative medium spiny neurons tended to fire more strongly under STOP trials, whereas putative interneurons exhibited both activity patterns.

Response inhibition is thought to improve throughout childhood and into adulthood. Despite the relationship between age and the ability to stop ongoing behavior, questions remain regarding whether these age-related changes reflect improvements in response inhibition or in other factors that contribute to response performance variability. Functional neuroimaging data shows age-related changes in neural activity during response inhibition. While traditional methods of exploring neuroimaging data are limited to determining correlational relationships, newer methods can determine predictability and can begin to answer these questions. Therefore, the goal of the current study was to determine which aspects of neural function predict individual differences in age, inhibitory function, response speed, and response time variability. We administered a stop-signal task requiring rapid inhibition of ongoing motor responses to healthy participants aged 9-30. We conducted a standard analysis using GLM and a predictive analysis using high-dimensional regression methods. During successful response inhibition we found regions typically involved in motor control, such as the ACC and striatum, that were correlated with either age, response inhibition (as indexed by stop-signal reaction time; SSRT), response speed, or response time variability. However, when examining which variables neural data could predict, we found that age and SSRT, but not speed or variability of response execution, were predicted by neural activity during successful response inhibition. This predictive relationship provides novel evidence that developmental differences and individual differences in response inhibition are related specifically to inhibitory processes. More generally, this study demonstrates a new approach to identifying the neurocognitive bases of individual differences.

The ability to stop a prepared response (reactive inhibition) appears to depend on the degree to which stopping is expected (proactive inhibition). Functional MRI studies have shown that activation during proactive and reactive inhibition overlaps, suggesting that the whole neural network for reactive inhibition becomes already activated in anticipation of stopping. However, these studies measured proactive inhibition as the effect of stop-signal probability on activation during go trials. Therefore, activation could reflect expectation of a stop-signal (evoked by the stop-signal probability cue), but also violation of this expectation because stop-signals do not occur on go trials. We addressed this problem, using a stop-signal task in which the stop-signal probability cue and the go-signal were separated in time. Hence, we could separate activation during the cue, reflecting expectation of the stop-signal, from activation during the go-signal, reflecting expectation of the stop-signal or violation of that expectation. During the cue, the striatum, the supplementary motor complex (SMC), and the midbrain activated. During the go-signal, the right inferior parietal cortex (IPC) and the right inferior frontal cortex (IFC) activated. These findings suggest that the neural network previously associated with proactive inhibition can be subdivided into two components. One component, including the striatum, the SMC, and the midbrain, activated during the cue, implicating this network in proactive inhibition. Another component, consisting of the right IPC and the right IFC, activated during the go-signal. Rather than being involved in proactive inhibition, this network appears to be involved in processes associated with violation of expectations. Hum Brain Mapp 34:2015-2024, 2013. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Contemporary models of ADHD hypothesize that hyperactivity reflects a byproduct of inhibition deficits. The current study investigated the relationship between children's motor activity and behavioral inhibition by experimentally manipulating demands placed on the limited-resource inhibition system. Twenty-two boys (ADHD = 11, TD = 11) between the ages of 8 and 12 years completed a conventional stop-signal task, two choice-task variants (no-tone, ignore-tone), and control tasks while their motor activity was measured objectively by actigraphs placed on their nondominant wrist and ankles. All children exhibited significantly higher activity rates under all three experimental tasks relative to control conditions, and children with ADHD moved significantly more than typically developing children across conditions. No differences in activity level were observed between the inhibition and noninhibition experimental tasks for either group, indicating that activity level was primarily associated with basic attentional rather than behavioral inhibition processes. [ABSTRACT FROM PUBLISHER]