Inhibitory mechanisms involved in Stroop-matching and stop-signal tasks and the role of impulsivity

Association between ADHD symptoms and inhibition-related brain activity using functional near-infrared spectroscopy (fNIRS)

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.

The Association Between Impulsivity and Relapse in Patients With Alcohol Use Disorder: A Literature Review

AIM

Impulsivity has been identified as a key relapse risk factor in patients with alcohol use disorder (AUD); however, the inherent characteristics of this relationship have been largely understudied. The heterogeneity of AUD and variation in impulsivity constructs require careful consideration to inform future work examining the relationship. This study sought to review empirical findings examining facets of impulsivity and AUD relapse.

METHODS

A systematic search strategy was employed to capture studies on impulsivity measures related to AUD relapse. Impulsivity measures were qualitatively organized in terms of 'trait impulsivity'-typically measured by self-report questionnaires-and 'behavioural impulsivity', i.e. 'motor impulsivity', 'impulsive choice' and 'reflection impulsivity, assessed with cognitive-behavioural tasks.

RESULTS

Seventeen peer-reviewed papers were identified. Relapse outcomes varied substantially in relation to impulsivity measures. Twelve papers included aspects of 'trait impulsivity', and nine studies included 'behavioural impulsivity' measures, from which five studies dealt with the 'impulsive choice' subcategory. The Barratt Impulsivity Scale was the self-report questionnaire that was most frequently used.

CONCLUSIONS

All three included facets of impulsivity ('trait-, motor- and impulsive choice impulsivity') were associated with AUD relapse, but none seemed to be superior to another. This study confirmed that research on the relation between impulsivity and AUD relapse is relatively scarce. Future research and treatment options are proposed.

Cognitive effectiveness of high-intensity interval training for individuals with methamphetamine dependence: a study protocol for randomised controlled trial

INTRODUCTION

Cognitive deficit is a common syndrome of methamphetamine (MA) dependence. It is related to decision-making, control ability, and social functioning. High-intensity interval training (HIIT) is a training technique that requires people to work out at full intensity during a short period. Many studies have already shown the potential effects of HIIT on cognitive functions. The purpose of this trial is to evaluate the cognitive effects of HIIT on individuals with MA dependence.

METHODS AND ANALYSIS

A total of 240 individuals with MA dependence will be randomly assigned to the HIIT group, moderate-intensity continuous training (MICT) group and control (CON) group. HIIT will consist of a 24-min HIIT exercise on a treadmill. MICT will consist of a 1-h body-mind exercise. CON will be their traditional intervention. The experimental period will be 12 months with 3 interventions weekly for the first 6 months and follow-up for the next 6 months. All subjects will be given cognitive tests at baseline, after intervention and at follow-up. Cognitive performances will be compared by a mixed-model analysis for repeated measures.

DISCUSSION

HIIT training may reduce illicit drug cravings amongst individuals with MA dependence; hence, HIIT may have a good effect on the cognitive functions, such as memory and executive function, of individuals with MA dependence.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2000032492 . Registered on April 30, 2020 ( http://www.chictr.org.cn/edit.aspx?pid=52127&htm=4 ).

Short intracortical facilitation associates with motor-inhibitory control

The ability of motor-inhibitory control is important in daily life. Inhibitory control deficits are commonly observed in psychiatric conditions with enhanced impulsivity. The physiological mechanisms underlying the inhibitory control deficits are not well elucidated. We systematically investigated the relationship between resting-state intracortical inhibition or facilitation and inhibitory control (indicated by stop signal reaction time, SSRT) to determine whether reduced intracortical inhibition or increased intracortical facilitation was related to the poorer inhibitory control. Thirty-three healthy subjects (age: 21.46 ± 1.40 years) participated in this study. We used paired-pulse transcranial magnetic stimulation to induce short intracortical inhibition, intracortical facilitation, long intracortical inhibition, and short intracortical facilitation at rest. SSRT was derived from stop signal task. We performed all measurements in two repeat sessions conducted two weeks apart. A negative correlation between short intracortical inhibition and SSRT was only observed in session 1; however, the correlation did not persist after controlling for short intracortical facilitation. Positive correlation between short intracortical facilitation and SSRT was observed in both sessions, indicating that individuals with greater resting-state short intracortical facilitation tend to have less efficient stopping performance. Our results help explain the inconsistency with respect to the relationship between short intracortical inhibition and SSRT in the existing literature. Short intracortical facilitation may be used as a potential physiological biomarker for motor-inhibitory control, which may have clinical implications for disorders associated with inhibitory control deficits.

Abnormal negative feedback processing in individuals with autistic traits in the Iowa gambling task: Evidence from behavior and event-related potentials

Value-based decision making plays an important role in social interaction. Previous studies have reported that individuals with autism spectrum disorder (ASD) exhibit deficits in terms of decision making. However, it is still unknown clearly whether individuals with high autistic traits within nonclinical populations employ abnormal neural substrates in value-based decision-making. To explore this issue, we investigated value-based decision making and its neural substrates in individuals with high and low autistic traits within a typically developing population who completed the revised Iowa gambling task (IGT) based on measurements of event-related potentials (ERPs). The IGT net scores were significantly lower in the group with high autistic traits than the group with low autistic traits in the fifth and sixth blocks. The ERP results showed that the feedback-related negativity (FRN) amplitude in individuals with high autistic traits allowed slight discrimination between positive and negative feedback in the low-risk option. The event-related spectral perturbations (ERSPs) and inter-trial coherence (ITC) of the theta-band frequency were also lower in the group with high autistic traits than the group with low autistic traits in the loss low-risk option. The results obtained in this study indicate that individuals with high autistic traits exhibit an unusual negative feedback process and relevant neural substrate. The FRN amplitude and theta-band oscillation may comprise a neural index of abnormal decision-making processes in individuals with high autistic traits. This study of a small sample may be considered an important step toward a more comprehensive understanding of the autism "spectrum" within a nonclinical population based on cognitive neuroscience.

Changes in Subjective Motivation and Effort During Sleep Restriction Moderate Interindividual Differences in Attentional Performance in Healthy Young Men

PURPOSE

The effects of sleep restriction on subjective alertness, motivation, and effort vary among individuals and may explain interindividual differences in attention during sleep restriction. We investigated whether individuals with a greater decrease in subjective alertness or motivation, or a greater increase in subjective effort (versus other participants), demonstrated poorer attention when sleep restricted.

PARTICIPANTS AND METHODS

Fifteen healthy men (M±SD, 22.3±2.8 years) completed a study with three nights of 10-hour time in bed (baseline), five nights of 5-hour time in bed (sleep restriction), and two nights of 10-hour time in bed (recovery). Participants completed a 10-minute psychomotor vigilance task (PVT) of sustained attention and rated alertness, motivation, and effort every two hours during wake (range: 3-9 administrations on a given day). Analyses examined performance across the study (first two days excluded) moderated by per-participant change in subjective alertness, motivation, or effort from baseline to sleep restriction. For significant interactions, we investigated the effect of study day² (day*day) on the outcome at low (mean-1 SD) and high (mean+1 SD) levels of the moderator (N = 15, all analyses).

RESULTS

False starts increased across sleep restriction in participants who reported lower (mean-1 SD) but not preserved (mean+1 SD) motivation during sleep restriction. Lapses increased across sleep restriction regardless of change in subjective motivation, with a more pronounced increase in participants who reported lower versus preserved motivation. Lapses increased across sleep restriction in participants who reported higher (mean+1 SD) but not preserved (mean-1 SD) effort during sleep restriction. Change in subjective alertness did not moderate the effects of sleep restriction on attention.

CONCLUSION

Vigilance declines during sleep restriction regardless of change in subjective alertness or motivation, but individuals with reduced motivation exhibit poorer inhibition. Individuals with preserved subjective alertness still perform poorly during sleep restriction, while those reporting additional effort demonstrate impaired vigilance.