Simple Response Inhibition Research Articles

Motor inhibition parameters are reflected in the kinetic and kinematic of gait initiation in a step version of the Stop Signal Task

Interacting with a continuously changing environment may necessitate cancelling a programmed movement, such as a step, after an environmental change to avoid errors and possible falls. This cancellation is successful if it occurs during the few milliseconds from the Anticipatory Postural Adjustments (APA) that precede the step onset, a period in which the center of mass (CoM) and the center of pressure (CoP) can still be aligned. Here we studied the inhibition of steps by the means of Stop Signal Task (SST), a behavioral task matched with a theoretical model developed to study the behavioral and physiological correlates of simple response inhibition [1], e.g., pressing a button. Aim of the present work was investigating if and how the inhibition of a complex multi-effectors movement as in step, accomplishes the assumptions of the model developed for simpler movements and if it is they are reflected in the time evolution of CoM and CoP. 12 healthy subjects (age: 33.3±7.1 y; weight: 69.3±17 kg; height: 169.7±8.2 cm) were required to initiate 300 walks from a stationary position (Go trials; GT) in response to the onset of an ahead pointing arrow (Go signal) on a pc monitor, and to interrupt the movement when in 30% of the trials (Stop trials; ST), a road stop signal (Stop signal) replaced the arrow after a variable time, determined using a behavioral tracking staircase algorithm [2]. A stereo-photogrammetric motion analysis system (SMART-DX 6000: BTS) and eight dynamometer platforms (Kistler 9286B; Kistler) were used to detect the kinematic and dynamic parameters of gait initiation. Ad-hoc analysis algorithms were developed by the MATLAB software (R2019b 9.7; MathWorks) to track the time evolution of CoM and CoP trajectories and capture the related reaction times (RT) for GT, error stop trials (eST), and correct stop trials (cST), and to conduct the statistical analysis. Fig. 1 displays the CoM (left upper panels) and CoP (left lower panels) trajectories in GT, eST, and cST, and the computed corresponding RT (rightmost panels). A repeated measures ANOVA and post-hoc tests detected (p<0.001), for both CoM and CoP, a significantly slowest RTs in cST (CoM=375±53ms; CoP=277±64ms), faster RT in GT (CoM=335±62ms; CoP=253±70ms), and the even faster in RT during the eST (CoM=296±61ms; CoP=213±64ms). By tracking the time evolution of CoM and CoP in a step version of the SST we obtained, during APA, a measure of RT, not only in GT and eST trials, but even in cST, a parameter hidden in the typical experimental setup. With these variables, we detected that the outcome of our version of SST complied with the main assumption of the race model: a movement is successfully cancelled when a stop process wins the race being faster than a go process. Accordingly, here we observed the eST were the trials approaching the race with significantly faster RT than cST. These results provide evidence that our version of SST is a valid tool for studying inhibition of complex movements and the associated kinematic variables.

An Investigation Into Response Inhibition in Distinct Clinical Groups Within Obsessive-Compulsive Disorder

Response inhibition has been frequently studied in obsessive-compulsive disorder (OCD) with mixed results. The inconsistent findings may stem in part from failure to consider the heterogeneity of the disorder. The authors examined behavioral and event-related potential (ERP) components (N2 and P3) during a simple response inhibition go/nogo task in a sample of patients with OCD (N=48) and control subjects (N=53). Comparisons in behavioral and electrophysiological measures were made between groups (OCD compared with control) and within the OCD group in terms of symptom clusters (symmetry, forbidden thoughts, and cleaning) and comorbidity status (OCD only and OCD with depression). In the OCD group, the N2 component appeared more frontally localized compared with the control group. Participants with OCD demonstrated longer N2 latency and a larger difference in N2 between the nogo and go conditions, suggesting slower but greater conflict monitoring. P3 had a larger amplitude in the OCD group compared with the control group, indicative of greater response inhibition, but was also reduced in the nogo compared with go condition, suggesting suppressed response inhibition. No significant differences were found between symptom clusters, but patients with OCD only made more omission errors compared with patients with OCD and comorbid depression. The latter cohort also had faster P3 latencies, which, combined with the behavioral data, indicates slightly improved response inhibition when comorbid depression is found. On the basis of these results, it would seem unlikely that symptom clusters have contributed to previous inconsistencies in the literature. Comorbid depression, which may have affected previous results, should be considered in future research.

Measuring and Predicting Individual Differences in Executive Functions at 14Months: A Longitudinal Study.

This study of 195 (108 boys) children seen twice during infancy (Time 1: 4.12 months; Time 2: 14.42 months) aimed to investigate the associations between and infant predictors of executive function (EF) at 14 months. Infants showed high levels of compliance with the EF tasks at 14 months. There was little evidence of cohesion among EF tasks but simple response inhibition was related to performance on two other EF tasks. Infant attention (but not parent‐rated temperament) at 4 months predicted performance on two of the four EF tasks at 14 months. Results suggest that EF skills build on simpler component skills such as attention and response inhibition.

Developmental Transactions Between Self-Regulation and Academic Achievement Among Low-Income African American and Latino Children.

This study examined the development of emerging self-regulation (SR) skills across the preschool years and relations to academic achievement in kindergarten and first grade. SR skills of 403 low-income African American and Latino children were measured at 2&1/2, 3&1/2, and 5years (kindergarten). Reading and math skills were measured at 5 and 6years (first grade) using the Woodcock-Johnson. Transactional relations between SR skills and achievement outcomes were estimated with latent difference score models. Increases in set shifting predicted prospective increases in reading, but not math scores. Increases in simple response inhibition predicted prospective increases in math, but not reading scores. Application of these findings to early intervention programming and needed supports for school readiness and achievement are discussed.

Selective attention relates to the development of executive functions in 2,5- to 3-year-olds: A longitudinal study

To study the central role of selective attention in the early development of executive functions (EFs), longitudinal relationships between selective attention, working memory, and simple response inhibition were explored. Selective attention, working memory, and simple response inhibition were assessed twice in our preschool sample (N=273), which included a relatively large number of children from low SES families. The tasks were administered between age 2.5 (time 1) and 3 years (time 2). An analytical path model was tested to analyse the relationships simultaneously. The results indicate that selective attention at age 2.5 years predicts working memory and response inhibition at age 3 years. Controlling for gender, SES, home language, verbal ability, and age did not affect the strengths of these relationships.

Prenatal tobacco exposure and response inhibition in school-aged children: An event-related potential study

Prenatal cigarette smoke exposure (PCSE) has been linked to problems in behavioral inhibition and attention deficit hyperactivity disorder in children in several epidemiological studies. We used event-related potentials (ERPs) to examine the effects of PCSE on neural correlates of inhibitory control of behavior. In a prospective longitudinal study on child development in the Canadian Arctic, we assessed 186 Inuit children (mean age=11.3years) on a visual Go/No-go response inhibition paradigm. PCSE was assessed through maternal recall. Potential confounders were documented from a maternal interview, and exposure to neurotoxic environmental contaminants was assessed from umbilical cord and child blood samples. PCSE was not related to behavioral performance on this simple response inhibition task. Nevertheless, this exposure was associated with smaller amplitudes of the N2 and P3 components elicited by No-go stimuli, suggesting an impairment in the neural processes underlying response inhibition. Amplitude of the No-go P3 component was also inversely associated with behavioral measures of externalizing problems and hyperactivity/impulsivity in the classroom. This study is the first to report neurophysiological evidence of impaired response inhibition in school-aged children exposed to tobacco smoke in utero. Effects were found on ERP components associated with conflict processing and inhibition of a prepotent response, indicating neurophysiological deficits that may play a critical role in the attention and behavior problems observed in children with PCSE.

Psychosis-Proneness and Neural Correlates of Self-Inhibition in Theory of Mind

Impaired Theory of Mind (ToM) has been repeatedly reported as a feature of psychotic disorders. ToM is crucial in social interactions and for the development of social behavior. It has been suggested that reasoning about the belief of others, requires inhibition of the self-perspective. We investigated the neural correlates of self-inhibition in nineteen low psychosis prone (PP) and eighteen high PP subjects presenting with subclinical features. High PP subjects have a more than tenfold increased risk of developing a schizophrenia-spectrum disorder. Brain activation was measured with functional Magnetic Resonance Imaging during a ToM task differentiating between self-perspective inhibition and belief reasoning. Furthermore, to test underlying inhibitory mechanisms, we included a stop-signal task. We predicted worse behavioral performance for high compared to low PP subjects on both tasks. Moreover, based on previous neuroimaging results, different activation patterns were expected in the inferior frontal gyrus (IFG) in high versus low PP subjects in self-perspective inhibition and simple response inhibition. Results showed increased activation in left IFG during self-perspective inhibition, but not during simple response inhibition, for high PP subjects as compared to low PP subjects. High and low PP subjects showed equal behavioral performance. The results suggest that at a neural level, high PP subjects need more resources for inhibiting the self-perspective, but not for simple motor response inhibition, to equal the performance of low PP subjects. This may reflect a compensatory mechanism, which may no longer be available for patients with schizophrenia-spectrum disorders resulting in ToM impairments.

Unique contributions of fathering to emerging self-regulation in low-income ethnic minority preschoolers

Self-regulation ability is an important component of school readiness and predictor of academic success, but few studies of self-regulation examine contributions of fathering to the emergence of self-regulation in low-income ethnic minority preschoolers. Associations were examined between parental child-oriented parenting support and preschoolers' emerging self-regulation abilities in 224 low-income African American (n = 86) and Latino (n = 138) children observed at age 30 months in father–child and mother–child interactions to determine unique predictions from fathering qualities. Child-oriented mothering but not fathering predicted greater simple response inhibition for both African American and Latino children. Fathering but not mothering quality uniquely predicted greater complex response inhibition, but only for the African American children. The culture-specific fathering effects could not be explained by differences in father involvement.

Shift in the Intrinsic Excitability of Medial Prefrontal Cortex Neurons following Training in Impulse Control and Cued-Responding Tasks

Impulse control is an executive process that allows animals to inhibit their actions until an appropriate time. Previously, we reported that learning a simple response inhibition task increases AMPA currents at excitatory synapses in the prelimbic region of the medial prefrontal cortex (mPFC). Here, we examined whether modifications to intrinsic excitability occurred alongside the synaptic changes. To that end, we trained rats to obtain a food reward in a response inhibition task by withhold responding on a lever until they were signaled to respond. We then measured excitability, using whole-cell patch clamp recordings in brain slices, by quantifying action potentials generated by the injection of depolarizing current steps. Training in this task depressed the excitability of layer V pyramidal neurons of the prelimbic, but not infralimbic, region of the mPFC relative to behavioral controls. This decrease in maximum spiking frequency was significantly correlated with performance on the final session of the task. This change in intrinsic excitability may represent a homeostatic mechanism counterbalancing increased excitatory synaptic inputs onto those neurons in trained rats. Interestingly, subjects trained with a cue that predicted imminent reward availability had increased excitability in infralimbic, but not the prelimbic, pyramidal neurons. This dissociation suggests that both prelimbic and infralimbic neurons are involved in directing action, but specialized for different types of information, inhibitory or anticipatory, respectively.

Target-Specific Encoding of Response Inhibition: Increased Contribution of AMPA to NMDA Receptors at Excitatory Synapses in the Prefrontal Cortex

Impulse control suppresses actions that are inappropriate in one context, but may be beneficial in others. The medial prefrontal cortex (mPFC) mediates this process by providing a top-down signal to inhibit competing responses, although the mechanism by which the mPFC acquires this ability is unknown. To that end, we examined synaptic changes in the mPFC associated with learning to inhibit an incorrect response. Rats were trained in a simple response inhibition task to withhold responding until a signal was presented. We then measured synaptic plasticity of excitatory synapses in the mPFC, using whole-cell patch-clamp recordings, in brain slices prepared from trained rats. Response inhibition training significantly increased the relative contribution of AMPA receptors to the overall EPSC in prelimbic, but not infralimbic, neurons of the mPFC. This potentiation of synaptic transmission closely paralleled the acquisition and extinction of response inhibition. Using a retrograde fluorescent tracer, we observed that these plastic changes were selective for efferents projecting to the ventral striatum, but not the dorsal striatum or amygdala. Therefore, we suggest that response inhibition is encoded by a selective strengthening of a subset of corticostriatal projections, uncovering a synaptic mechanism of impulse control. This information could be exploited in therapeutic interventions for disorders of impulse control, such as addiction, attention deficit-hyperactivity disorder, and schizophrenia.

Inhibitory Control in High-Functioning Autism: Decreased Activation and Underconnectivity in Inhibition Networks

Inhibiting prepotent responses is critical to optimal cognitive and behavioral function across many domains. Several behavioral studies have investigated response inhibition in autism, and the findings varied according to the components involved in inhibition. There has been only one published functional magnetic resonance imaging (fMRI) study so far on inhibition in autism, which found greater activation in participants with autism than control participants. This study investigated the neural basis of response inhibition in 12 high-functioning adults with autism and 12 age- and intelligence quotient (IQ)-matched control participants during a simple response inhibition task and an inhibition task involving working memory. In both inhibition tasks, the participants with autism showed less brain activation than control participants in areas often found to be active in response inhibition tasks, namely the anterior cingulate cortex. In the more demanding inhibition condition, involving working memory, the participants with autism showed more activation than control participants in the premotor areas. In addition to the activation differences, the participants with autism showed lower levels of synchronization between the inhibition network (anterior cingulate gyrus, middle cingulate gyrus, and insula) and the right middle and inferior frontal and right inferior parietal regions. The results indicate that the inhibition circuitry in the autism group is activated atypically and is less synchronized, leaving inhibition to be accomplished by strategic control rather than automatically. At the behavioral level, there was no difference between the groups.

Altered functional neuroanatomy of response inhibition in adolescent males who were born very preterm

Event-related functional magnetic resonance imaging (fMRI) was used to investigate the hypothesis that males who were born very preterm may show differences in relative strength of blood oxygen level dependent (BOLD) signals in selective brain areas during performance of a simple response inhibition task compared with term-born controls. Participants were eight males (mean gestational age at birth 28wks, [SD 2]; mean age at testing 16y, [SD 1] and 14 controls matched for sex, age (mean age 17y, [SD 1]), and IQ. A 'go-no-go' task was used to assess response selection and motor response inhibition in response to a visual stimulus. When the 'no-go' condition was contrasted with an attentional control condition, preterm participants showed reduced BOLD signal response bilaterally in the cerebellum, right caudate nucleus, and thalamus, and prefrontal areas including left inferior prefrontal and left anterior cingulate gyri. They also showed increased response mainly in temporal regions. These results suggest that despite good task performance, individuals who were born very preterm exhibit different BOLD signal responses in selective brain areas compared with controls which may underline the use of alternative strategies when challenged with motor response inhibition processing.