Behavioral Inhibition Deficits Research Articles

EEG biomarkers of behavioral inhibition in patients with depression who committed violent offenses: a Go/NoGo ERP study.

Understanding the neurobiological correlates of behavioral inhibition in patients with depression who committed violent offenses could contribute to the prediction and prevention of violence. The present study recruited 29 depressed patients with violent offenses (VD group), 27 depressed patients without violent behavior (NVD group), and 28 healthy controls (HC group) to complete a visual Go/NoGo task, during which their responses and electroencephalography were simultaneously recorded using an event-related potentiometer. The results showed that the VD group made more commission errors and responded more slowly relative to the NVD and HC groups. The P3 amplitude of the VD group was reduced in the frontal and central brain regions compared to the HC group and increased in the parietal regions compared to the NVD group. In comparison to Go stimuli, NoGo stimuli induced longer P3 latencies in frontal regions in both the VD and NVD groups; however, this difference was not statistically significant in the HC group. These results provide electrophysical evidence of behavioral inhibition deficits in patients with depression, especially in those with violent behaviors. The reduced P3 amplitude in the frontal-central regions, increased P3 amplitude in the parietal regions, and increased NoGo P3 latency may be potential electrophysiological features that can predict violent behavior in patients with depression.

Neurocognitive features of military personnel with deviant behavior

Relevance. The low accuracy of deviant behavior (DB) detecting and predicting in military personnel using questionnaire methods underlines the need to search for new, more reliable approaches, in a number of which behavioral methods in the paradigm of Research Domain criteria are of particular interest, because they reveal biological prerequisites for deviant behavior, which is extremely important for improving occupational psychological selection.Intention – to study the features of neurocognitive functions in military personnel with deviant behavior in order to improve the methods of its diagnosis.Methodology. 3 groups of servicemen were examined: 1 st (n = 16) – with a predominance of internalizing behavior (suicidal forms of DB, F43.20 by ICD-10); 2nd (n = 21) – with externalizing patterns of behavior (addictive and asocial forms of DB, F34.0, F43.24, F61.0 by ICD-10); 3rd (n = 24) – mentally healthy servicemen. The following methods were used: “Stop signal”, Stroop test, “Affective priming”; 4) Iowa gambling task.Results and Discussion. The examination revealed the following: 1) according to the “Stop signal” test: in groups 1 and 2, there was a predominance of the priority of response speed over accuracy with a reduced response time in case of action and inaction reactions; 2) according to the Stroop test: in groups 1 and 2, increased number of errors in congruent responses and the average reaction time in congruent and incongruent types of responses, as well as the Stroop effect magnitudes were detected; 3) according to the “Affective priming” method: in groups 1 and 2, there was a reduced difference in the time of response during congruent and incongruent preconditioning to negative and positive stimuli; 4) according to the Iowa gambling task: the ability to learn based on emotional feedback in groups 1 and 2 was significantly lower than in group 3; sensitivity to punishment was also maximum in group 3, in group 1 it was significantly lower, while in group 2 it was of a paradoxical, inverted nature.Conclusion. The neurobiological basis for increased predisposition to deviant behavior is excessive impulsivity due to a deficit in cognitive and behavioral inhibition, as well as a lower sensitivity of the affective response system. The use of neurocognitive tests for measuring individual indicators of impulsivity and affective response will improve the accuracy and reliability of predicting deviant behavior in military personnel, and the impact on these biological targets will effectively correct these behavioral phenomena.

Cognitive and Behavioral Inhibition Deficits in Parkinson's Disease: The Hayling Test as a Reliable Marker.

ObjectiveThe present study seeks to provide an overview of executive (inhibition and flexibility) deficits in Parkinson’s disease (PD) by combining a cognitive and behavioral approach.MethodsFifteen PD patients and 15 healthy controls underwent a neuropsychological and behavioral assessment including the Hayling and Trails Tests, the Questionnaire for Impulsive–Compulsive Disorders in Parkinson’s Disease (QUIP-RS), the Behavior Rating Inventory of Executive Function (BRIEF-A), and the Short Form-36 Health Survey (SF-36). The level of awareness of executive functioning was also analyzed. We finally explored how these neuropsychological and clinical outcomes could relate to each other.ResultsPD patients performed significantly worse in both neuropsychological tasks designed to evaluate inhibition abilities. They also reported more inhibition difficulties in everyday life and poorer quality of life. Associations between neuropsychological measures and self-reports were found. Moreover, as indicated by the discrepancy score, PD patients were as accurate as their relatives in self-reporting their executive daily difficulties.ConclusionInhibition and cognitive flexibility impairments assessed by the neuropsychological tests (Hayling and Trails tests) seem to capture daily life executive problems in PD. Furthermore, our study provides a deeper understanding of PD patients’ and their relatives’ experience of these executive dysfunctions.

Frontotemporal dementia subtypes based on behavioral inhibition deficits.

IntroductionWe aimed to investigate phenotypic heterogeneity in the behavioral variant of frontotemporal dementia (bvFTD) through assessment of inhibition deficits.MethodsWe assessed occurrences of 16 behavioral inhibition deficits from video recordings of 15 bvFTD patients (early stage) and 15 healthy controls (HC) in an ecological setting. We extracted dimensions of inhibition deficit and analyzed their correlations with cognitive and clinical measures. Using these dimensions, we isolated patient clusters whose atrophy patterns were explored.ResultsAfter identifying two patterns of inhibition deficit (compulsive automatic behaviors and socially unconventional behaviors), we isolated three behavioral clusters with distinct atrophy patterns. BvFTD‐G0 (N = 3), an outlier group, showed severe behavioral disturbances and more severe ventromedial prefrontal cortex/orbitofrontal cortex atrophy. Compared to bvFTD‐G1 (N = 6), bvFTD‐G2 (N = 6) presented higher anxiety and depression along with less diffuse atrophy especially in midline regions.DiscussionIdentifying clinico‐anatomical profiles through behavior observation could help to stratify bvFTD patients for adapted treatments.

Reduced Proactive Control Processes Associated With Behavioral Response Inhibition Deficits in Autism Spectrum Disorder.

Impairments in inhibitory control are common in individuals with autism spectrum disorder (ASD) and associated with multiple clinical issues. Proactive (i.e., delaying response onset) and reactive control mechanisms (i.e., stopping quickly) contribute to successful inhibitory control in typically developing individuals and may be compromised in ASD. We assessed inhibitory control in 58 individuals with ASD and 63 typically developing controls aged 5-29 years using an oculomotor stop-signal task during which participants made rapid eye movements (i.e., saccades) toward peripheral targets (i.e., GO trials) or inhibited saccades (i.e., STOP trials). Individuals with ASD exhibited reduced ability to inhibit saccades, reduced reaction time slowing (GO RT slowing), and faster stop-signal reaction times (SSRT) compared to controls. Across participants, stopping accuracy was positively related to GO RT slowing, and increased age was associated with higher stopping accuracy and GO RT slowing. Our results indicate that failures to proactively delay prepotent responses in ASD underpin deficits of inhibitory control and may contribute to difficulties modifying their behavior according to changes in contextual demands. These findings implicate frontostriatal brain networks in inhibitory control and core symptoms of ASD. LAY SUMMARY: Difficulties stopping actions are common in individuals with autism spectrum disorder (ASD) and are related to repetitive behaviors. This study compared the ability to stop eye movements in individuals with ASD and healthy peers. We found that individuals with ASD were less able to stop eye movements and that this difficulty was related to a reduced ability to delay their eye movements before seeing the cue to stop, not their ability to react quickly to this cue.

Hemodynamic and behavioral peculiarities in response to emotional stimuli in children with attention deficit hyperactivity disorder: An fNIRS study

BackgroundChildren with attention deficit hyperactivity disorder (ADHD) exhibit behavioral inhibition deficits, which often lead to emotional dysregulation (ED) affecting individual ability to control emotions and behavioral responses. In ADHD, ED is associated with poor outcomes and comorbidities, with both externalizing and internalizing disorders. This work aims to evaluate sensitivity to emotional stimuli in children with ADHD using functional Near Infrared Spectroscopy (fNIRS). MethodsDuring frontal fNIRS recording, 20 children with ADHD and 25 typically developing (TD) peers performed a visual continuous performance task with stimuli of different emotional content (i.e., positive, negative, neutral, and control stimuli without emotional content). This is a cognitive task designed to evaluate the ability to recognize emotional stimuli and to deal with emotional interference. ResultsThe ADHD sample showed more variability in response time to stimuli and more false alarms compared to TD group. fNIRS data showed between-group differences in right prefrontal and frontal cortices, with wider hemoglobin concentration changes in the TD group, during positive, negative, and neutral conditions. LimitationsOwing to the limited possibility of near infrared light to penetrate tissue, fNIRS can only measure cortical activations, while it would be of interest to identify the subcortical areas linked to emotional processing, too. ConclusionsFindings suggest the presence of emotional processing deficits in children with ADHD, as suggested by poor performances on the e-CPT task, and of peculiar sensitivity to emotional stimuli, linked to atypical hemodynamics of right prefrontal and frontal areas.

Guanfacine treatment improves ADHD phenotypes of impulsivity and hyperactivity in a neurofibromatosis type 1 mouse model

BackgroundNeurofibromatosis type 1 (NF1) is an autosomal dominant disorder with a mutation in one copy of the neurofibromin gene (NF1+/−). Even though approximately 40–60% of children with NF1 meet the criteria for attention deficit hyperactivity disorder (ADHD), very few preclinical studies, if any, have investigated alterations in impulsivity and risk-taking behavior. Mice with deletion of a single NF1 gene (Nf1+/−) recapitulate many of the phenotypes of NF1 patients.MethodsWe compared wild-type (WT) and Nf1+/− mouse strains to investigate differences in impulsivity and hyperactivity using the delay discounting task (DDT), cliff avoidance reaction (CAR) test, and open field. We also investigated whether treatment with the clinically effective alpha-2A adrenergic receptor agonist, guanfacine (0.3 mg/kg, i.p.), would reverse deficits observed in behavioral inhibition.ResultsNf1+/− mice chose a higher percentage of smaller rewards when both 10- and 20-s delays were administered compared to WT mice, suggesting Nf1+/− mice are more impulsive. When treated with guanfacine (0.3 mg/kg, i.p.), Nf1+/− mice exhibited decreased impulsive choice by waiting for the larger, delayed reward. Nf1+/− mice also exhibited deficits in behavioral inhibition compared to WT mice in the CAR test by repetitively entering the outer edge of the platform where they risk falling. Treatment with guanfacine ameliorated these deficits. In addition, Nf1+/− mice exhibited hyperactivity as increased distance was traveled compared to WT controls in the open field. This hyperactivity in Nf1+/− mice was reduced with guanfacine pre-treatment.ConclusionsOverall, our study confirms that Nf1+/− mice exhibit deficits in behavioral inhibition in multiple contexts, a key feature of ADHD, and can be used as a model system to identify alterations in neural circuitry associated with symptoms of ADHD in children with NF1.

Familiality of behavioral flexibility and response inhibition deficits in autism spectrum disorder (ASD)

BackgroundDiminished cognitive control, including reduced behavioral flexibility and behavioral response inhibition, has been repeatedly documented in autism spectrum disorder (ASD). We evaluated behavioral flexibility and response inhibition in probands and their parents using a family trio design to determine the extent to which these cognitive control impairments represent familial traits associated with ASD.MethodsWe examined 66 individuals with ASD (probands), 135 unaffected biological parents, and 76 typically developing controls. Participants completed a probabilistic reversal learning task (PRL) and a stop-signal task (SST) to assess behavioral flexibility and response inhibition respectively. Rates of PRL and SST errors were examined across groups, within families, and in relation to clinical and subclinical traits of ASD. Based on prior findings that subclinical broader autism phenotypic (BAP) traits may co-segregate within families and reflect heritable risk factors, we also examined whether cognitive control deficits were more prominent in families in which parents showed BAP features (BAP+).ResultsProbands and parents each showed increased rates of PRL and SST errors relative to controls. Error rates across tasks were not related. SST error rates inter-correlated among probands and their parents. PRL errors were more severe in BAP+ parents and their children relative to BAP− parents and their children. For probands of BAP+ parents, PRL and SST error rates were associated with more severe social-communication abnormalities and repetitive behaviors, respectively.ConclusionReduced behavioral flexibility and response inhibition are present among probands and their unaffected parents, but represent unique familial deficits associated with ASD that track with separate clinical issues. Specifically, behavioral response inhibition impairments are familial in ASD and manifest independently from parental subclinical features. In contrast, behavioral flexibility deficits are selectively present in families with BAP characteristics, suggesting they co-segregate in families with parental subclinical social, communication, and rigid personality traits. Together, these findings provide evidence that behavioral flexibility and response inhibition impairments track differentially with ASD risk mechanisms and related behavioral traits.

Abnormal Neural Activity in Children With Diffuse Intrinsic Pontine Glioma Had Manifested Deficit in Behavioral Inhibition: A Resting-State Functional MRI Study.

The purpose of this study was to investigate whether alterations of regional neural function in children with diffuse intrinsic pontine glioma (DIPG) had manifested deficit in behavioral inhibition using resting-state functional MRI (rs-fMRI). There were 17 participants with DIPG who took part in the study. Eight children were with deficit in behavioral inhibition, whereas the other 9 children did not obtain deficit in behavioral inhibition. Five healthy children with age, sex, and education matched to the study group also participated as the control group. These 3 groups underwent rs-fMRI, and the results were then converted to amplitude of low-frequency fluctuation (ALFF) data. Amplitude of low-frequency fluctuation data were further analyzed by single-factor analysis of variance comparing among 3 groups based on the whole brain levels. Amplitude of low-frequency fluctuation results were subjected to t test of voxel-wised comparison to derive the rs-fMRI brain function differences between the 2 DIPG groups. The Pearson correlation between ALFF values of abnormal regions found in 3 groups and the scores obtained according to the Child Behavior Checklist were analyzed. The 3 groups had shown significant differences in terms of the ALFF results, with the ALFF increased in several brain regions (P < 0.05, corrected with AlphaSim, clusters >59 voxels), which include left supramarginal gyrus, left dorsolateral superior frontal gyrus, right precentral gyrus, and right middle frontal gyrus. Participants with deficit in behavioral inhibition had shown significant differences (ALFF decreased) in several brain regions, including left dorsolateral superior frontal gyrus and right fusiform gyrus (P < 0.05, corrected with AlphaSim, clusters >123 voxels), whereas other brain regions had shown ALFF increased, including left supramarginal gyrus, left middle frontal gyrus, and right medial superior frontal gyrus (P < 0.05, corrected with AlphaSim, clusters >123 voxels). There was no significant correlation between ALFF values and Child Behavior Checklist scores (P > 0.05). These findings of focal spontaneous hyperfunction and hypofunction, which correlate with deficit in behavioral inhibition processing, and the abnormal brain regions are considered to be inefficient (in regions of the brain that may relate to compensatory brain and behavioral functioning, and it may be that the brain region needs to exert extra energy to perform a task to the same degree as the control group) or inability (inability in a certain region, or underpowered), pointing to a pathophysiologic process in executive dysfunction.

Anticonvulsant medications attenuate amphetamine-induced deficits in behavioral inhibition but not decision making under risk on a rat gambling task

Impulsivity is a major component of mania in bipolar disorder (BD), and patients also show impairments in decision-making involving risk on the Iowa Gambling Task (IGT). Similar deficits are observed in some patients with temporal lobe epilepsy (TLE), and incidence of problem gambling is higher in both these populations. Anticonvulsant drugs are widely used in the treatment of epilepsy, but also as mood stabilizers and prophylaxis for the management of BD. Unfortunately, little is still known about the precise mechanisms of action underlying their efficacy, and the specific behavioral aspect targeted by these drugs. This project explored the effect of the three anticonvulsant drugs currently also used as mood stabilizers- carbamazepine, valproate and lamotrigine on aspects of decision-making using a rat analogue of the IGT, the rat Gambling Task (rGT). In this task, rats choose between four distinct, probabilistic reinforcement schedules. Sugar pellet profits are maximized by adopting a conservative strategy, avoiding tempting high-risk, high-reward options. Effects of the anticonvulsant agents were assessed on baseline performance and also in conjunction with amphetamine administration, in order to approximate a “mania-like” state. Carbamazepine appeared to slow processing speed, decreasing premature responses and increasing choice latency, whereas valproate and lamotrigine had no effect. When administered prior to amphetamine, lamotrigine was the only drug that failed to attenuate the pro-impulsive effect of the psychostimulant. Further studies looking at chronic administration of anticonvulsants may help us understand the impact of this medication class on decision-making and impulsivity in healthy rats and disease models.

EP 80. Sexual processing of pedophilic patients and healthy controls and the role of its metabolic markers – A fMRI and MRS study

Introduction We aimed to investigate differential activation patterns in brain areas subserving attentional control of behavior and perception of salient stimuli in pedophilia using ultra-high magnetic resonance imaging (fMRI). Moreover, we wanted to measure whether behavioral inhibition deficits can be observed in those brain regions on the level of inhibitory neurotransmitter using magnetic resonance spectroscopy (MRS). Previous neuroimaging studies underlined the crucial role of the dorsalanterior cingulate cortex (dACC) in sexual anticipation processes, impulse control, reward based decision making as well as in attention modulation We designed a paradigm to expose whether pedophilic patients show any different effects when expecting pictures of naked children in comparison to healthy controls. We hypothesized stronger dACC responses in pedophilic patients during expectancy of naked children pictures, compared to healthy controls. During expectancy of naked adult pictures we hypothesized inverse activation patterns in both groups. Furthermore, we assumed that child sexual offending may be linked to decreased GABA levels in dACC. Methods 13 pedophilic patients and 13 age-, gender- and handedness matched healthy controls underwent a 7 Tesla MRI. Seven patients were under antiandrogen therapy causing a lower testosteron level. All patients had committed sexual offenses against children. The number of victims sexually assaulted by the offenders ranged from 1 to 13 (mean: 5, 62 ± 3,61). Subjects percieved pictures of naked adults and naked children in a randomized order. Half of the pictures were preceded by an expectancy cue. Participants were instructed to actively expect a picture depending on the cue (↑ = adult, ↓ = child). MRS data was acquired during rest before the expectancy task. MRS data was obtained using STEAM sequence and analyzed using LCModel. fMRI data was preprocessed and analyzed (two-sample t -test) in SPM8 and SPSS20.0. Results 1) Patients showed stronger dACC activation than healthy controls when expecting child pictures as compared to expecting adult pictures (two sample t -Test, covariate of no interest: age, p 2) Pedophiles show reduced GABA in dACC compared to healthy control subjects: One-way ANOVA controlling for age and gray matter content revealed significant effect for group on dACC GABA levels ( p t -test revealed that patients had significantly lower GABA/Cr in dACC ( p Conclusion Pedophiles with a history of child sexual offending show abnormal BOLD signal changes during anticipation processes in brain areas associated with cognitive control and attention in. In our study the activity in dACC is a predictor for the sexual salience of the following pictures. Functional abnormalities in dACC overlap with abnormal GABAergic metabolism in pedophilic patients. MRS results reveal significantly lower GABA levels in dACC which may be seen as a neuronal correlate of disinhibition. We assume lower GABA levels being associated with a decreased ability to control motor responses and sexual drives.

Mifepristone Treatment during Early Adolescence Fails to Restore Maternal Deprivation-Induced Deficits in Behavioral Inhibition of Adult Male Rats.

Early life adversity has a profound impact on brain development and later life health. Animal models have provided insight how early life stress programs stress responsiveness and might contribute to the development of psychiatric disorders. In the present study, the long-term effects of maternal deprivation (MD) on behavioral inhibition and attention were examined in adult male Wistar rats. To this end animals were tested in the 5-choice serial reaction time task (5-choice SRTT). We also explored the potential of a 3-day treatment with the glucocorticoid receptor (GR) antagonist mifepristone during early adolescence to normalize putative behavioral effects of early life stress. Deprivation of the mother for 24 h on postnatal day (PND) 3 led to a modest but significant increase in premature responses in the 5-choice SRTT, but did not affect measures of attention. Body weight was lower in deprived animals from weaning until the start of testing. Early adolescent mifepristone treatment (PND 26–28) did not influence performance on the 5-choice SRTT and did not mitigate the deprivation-related impairment in behavioral inhibition. Our results indicate that MD leads to impaired behavioral inhibition, and that mifepristone treatment during early adolescence does not normalize the behavioral changes caused by early life stress.

Working memory and behavioral inhibition in boys with ADHD: An experimental examination of competing models

ABSTRACTWorking memory (WM) and behavioral inhibition impairments have garnered significant attention as candidate core features, endophenotypes, and/or associated neurocognitive deficits of attention-deficit/hyperactivity disorder (ADHD). The relationship between ADHD-related WM and inhibition deficits remains relatively unclear, however, with inferences about the constructs’ directional relationship stemming predominantly from correlational research. The current study utilized a dual-task paradigm to experimentally examine the relationship between ADHD-related WM and behavioral inhibition deficits. A total of 31 boys (15 ADHD and 16 typically developing [TD]) aged 8–12 years completed WM (1-back and 2-back), behavioral inhibition (stop-signal task [SST]), and dual-condition (1-back/SST and 2-back/SST) experimental tasks. Children with ADHD exhibited significant, large-magnitude WM deficits for the 1-back condition but were not significantly different from children in the TD group for the 2-back, 1-back/SST, and 2-back/SST conditions. Children with ADHD also exhibited significant inhibition deficits for the SST, 1-back/SST, and 2-back/SST conditions, but the within-group effect was not significant. The findings suggest that ADHD-related stop-signal demands are upstream, or compete for, resources involved in controlled-focused attention and/or other central executive (CE), WM processes.

Examining cognitive emotion regulation infrontal lobe patients: The mediating role ofresponse inhibition.

Previous investigations have demonstrated the relationship between inhibitory deficits and maladaptive emotion regulation. Although several neuropsychological studies show that frontal lobe damage can lead to extreme inhibition impairments, there have been no investigations regarding the influence of frontal lobe damage and related inhibition impairments on the use of maladaptive strategies. The goal of the current study was to examine the impact of executive functions impairments due to frontal lobe damage on cognitive emotion regulation. Fifteen patients with frontal lobe damage were compared to twenty-two healthy controls on their reported use of maladaptive strategies. The effect of behavioral inhibition deficits among the frontal lobe damage group was examined. Patients reflected a heightened use of maladaptive strategies compared to healthy controls, significantly mediated by Go/NoGo task errors, which are an indicator for response inhibition deficits. Results suggest that a heightened use of maladaptive strategies by patients relies to a strong extent on their impaired impulse control, highlighting the complex interplay between executive functions and emotional regulation.

Gambling addiction: insights from neuroscience and neuroimaging

Although most people consider gambling as a recreational activity, some individuals lose control over their behavior and enter a spiral of compulsive gambling leading to dramatic consequences. In its most severe form, pathological gambling is considered a behavioral addiction sharing many similarities with substance addiction. A number of neurobiological hypotheses have been investigated in the past ten years, relying mostly on neuroimaging techniques. Similarly to substance addiction, a number of observations indicate a central role for dopamine in pathological gambling. However, the underlying mechanism seems partly different and is still poorly understood. Neuropsychological studies have shown decision-making and behavioral inhibition deficits in pathological gamblers, likely reflecting frontal lobe dysfunction. Finally, functional MRI studies have revealed abnormal reactivity within the brain reward system, including the striatum and ventro-medial prefrontal cortex. These regions are over-activated by gambling cues, and under-activated by monetary gains. However, the scarcity and heterogeneity of brain imaging studies currently hinder the development of a coherent neurobiological model of pathological gambling. Further replications of results and diversification of approaches will be needed in the coming years in order to strengthen our current model.

Distinguishing Adolescents With ADHD From Their Unaffected Siblings and Healthy Comparison Subjects by Neural Activation Patterns During Response Inhibition.

Dysfunctional response inhibition is a key executive function impairment in attention deficit hyperactivity disorder (ADHD). Still, behavioral response inhibition measures do not consistently differentiate affected from unaffected individuals. The authors therefore investigated neural correlates of response inhibition and the familial nature of these neural correlates. Functional MRI measurements of neural activation during the stop-signal task and behavioral measures of response inhibition were obtained in adolescents and young adults with ADHD (N=185), their unaffected siblings (N=111), and healthy comparison subjects (N=124). Stop-signal task reaction times were longer and error rates were higher in participants with ADHD, but not in their unaffected siblings, while reaction time variability was higher in both groups than in comparison subjects. Relative to comparison subjects, participants with ADHD and unaffected siblings had neural hypoactivation in frontal-striatal and frontal-parietal networks, whereby activation in inferior frontal and temporal/parietal nodes in unaffected siblings was intermediate between levels of participants with ADHD and comparison subjects. Furthermore, neural activation in inferior frontal nodes correlated with stop-signal reaction times, and activation in both inferior frontal and temporal/parietal nodes correlated with ADHD severity. Neural activation alterations in ADHD are more robust than behavioral response inhibition deficits and explain variance in response inhibition and ADHD severity. Although only affected participants with ADHD have deficient response inhibition, hypoactivation in inferior frontal and temporal-parietal nodes in unaffected siblings supports the familial nature of the underlying neural process. Activation deficits in these nodes may be useful as endophenotypes that extend beyond the affected individuals in the family.

Overexpression of the type 1 adenylyl cyclase in the forebrain leads to deficits of behavioral inhibition.

The type 1 adenylyl cyclase (AC1) is an activity-dependent, calcium-stimulated adenylyl cyclase expressed in the nervous system that is implicated in memory formation. We examined the locomotor activity, and impulsive and social behaviors of AC1+ mice, a transgenic mouse strain overexpressing AC1 in the forebrain. Here we report that AC1+ mice exhibit hyperactive behaviors and demonstrate increased impulsivity and reduced sociability. In contrast, AC1 and AC8 double knock-out mice are hypoactive, and exhibit increased sociability and reduced impulsivity. Interestingly, the hyperactivity of AC1+ mice can be corrected by valproate, a mood-stabilizing drug. These data indicate that increased expression of AC1 in the forebrain leads to deficits in behavioral inhibition.

CONTRIBUTION TO THE DEVELOPMENT OF INTERIOR SPACES IN HYPERACTIVITY AND DISTRACTED ATTENTION: AN ANALYTICAL CASE STUDY

Attention deficit hyperactivity disorder (ADHD) comprises a deficit in behavioral inhibition, a condition affecting increasing numbers of people annually. The study of proper spaces, their design methodology, and adequate learning environments, especially in schools, for a particular class of people is required in developing a design methodology of spaces for children who suffer from hyperactivity and distracted attention by allocating proper design spaces that satisfy general and special considerations. However, this methodology depends on contributing to the development of different interior spaces for children with ADHD to achieve the same goals, that is, a rich opportunity to create sufficient spaces for such children. The aim of this study is to develop a design methodology that reflects the foundations and considerations of interior design in the context of the Saudi Code to design special places for people with special needs according to principles of sustainable material use.

General and food‐specific inhibitory deficits in binge eating disorder

To investigate behavioral inhibition in individuals with binge eating disorder (BED) compared with overweight and obese individuals without BED (No-BED). Participants with BED (n = 31) and the weight-matched No-BED group (n = 29) completed an inhibitory control task (stop-signal task, SST) with food and neutral stimuli. The BED group needed more time to stop an ongoing response, as indicated by increased stop signal reaction time (SSRT) relative to the No-BED group. Additionally, compared with the No-BED group, the BED group displayed more difficulty inhibiting responses elicited by food stimuli. The deficits in behavioral response inhibition were also found to be related to the severity of reported symptoms. There is a general deficit in late stage behavioral inhibition in BED, and this may be particularly pronounced in the context of food stimuli.

Response inhibition is impaired by developmental methylmercury exposure: Acquisition of low-rate lever-pressing

Developmental methylmercury (MeHg) exposure produces response perseveration on discrimination reversal procedures, disrupts sensitivity to reinforcement, and enhances sensitivity to dopamine agonists – a profile suggesting a deficit in behavioral inhibition. To examine inhibition, we examined MeHg's effects on the acquisition and persistence of low-rate lever-pressing following a history of high-rate responding. Additionally, we examined whether chronic exposure to selenium protects against MeHg's developmental neurotoxicity. Female rats were exposed in utero via maternal exposure to drinking water containing 0ppm, 0.5ppm or 5ppm of Hg as MeHg, producing approximately 0μg/kg/day, 40μg/kg/day, or 400μg/kg/day of Hg. The mothers (during gestation) and the offspring (throughout life) consumed a purified diet containing 0.06ppm or 0.6ppm of Se (as sodium selenite), forming a 2 (lifespan diet)×3 (developmental MeHg) factorial design. Adult offspring lever-pressed under two schedules of reinforcement. A differential reinforcement of high-rate (DRH) schedule imposed rigid response requirements that remained constant through the study. A high-rate percentile schedule (PCNT-H) incorporated a flexible criterion that reinforced short interresponse times using an adjusting criterion that was sensitive to recent performance. After high-rate responding stabilized, the PCNT-H schedule was abruptly inverted by reinforcing long interresponse times. Acquisition of low-rate responding was impaired in the MeHg-exposed rats because of intrusions of high-rate response bursts. DRH response rates did not change. Dietary selenium did not influence MeHg's effects. High-rate operant behavior perseverated, suggesting that gestational MeHg exposure impairs response inhibition – an effect that extends results previously reported using choice procedures or spatial and visual discrimination reversals.