Response inhibition is essential for navigating everyday life. Its derailment is considered integral to numerous neurological and psychiatric disorders, and more generally, to a wide range of behavioral and health problems. Response-inhibition efficiency furthermore correlates with treatment outcome in these conditions. The stop-signal task is an essential tool to determine how quickly response inhibition is implemented. Despite its apparent simplicity, there are many features (ranging from task design to data analysis) that vary across studies in ways that can easily compromise the validity of the obtained results. Our present goal is to facilitate a more accurate use of the stop-signal task. To this end, we provide twelve easy-to-implement consensus recommendations and point out the problems that can arise when these are not followed. This article is furthermore accompanied by user-friendly open-source resources intended to inform statistical-power considerations, facilitate the correct implementation of the task, and assist in proper data analysis.

BackgroundImpairments in facial mimicry are considered a proxy for deficits in affective empathy and have been demonstrated in 10 year old children and in adolescents with disruptive behavior disorder (DBD). However, it is not known whether these impairments are already present at an earlier age. Emotional deficits have also been shown in children with attention-deficit/hyperactivity disorder (ADHD).AimsTo examine facial mimicry in younger, 6–7 year old children with DBD and with ADHD.MethodsElectromyographic (EMG) activity in response to emotional facial expressions was recorded in 47 children with DBD, 18 children with ADHD and 35 healthy developing children.ResultsAll groups displayed significant facial mimicry to the emotional expressions of other children. No group differences between children with DBD, children with ADHD and healthy developing children were found. In addition, no differences in facial mimicry were found between the clinical group (i.e., all children with a diagnosis) and the typically developing group in an analysis with ADHD symptoms as a covariate, and no differences were found between the clinical children and the typically developing children with DBD symptoms as a covariate.ConclusionFacial mimicry in children with DBD and ADHD throughout the first primary school years was unimpaired, in line with studies on empathy using other paradigms.

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: Introduction: Smoking is associated with significant negative health consequences. It has been suggested that deficient inhibitory control may be implicated in (nicotine) addiction, but its exact role has not yet been elucidated. In the current study, our aim was to investigate the role of inhibitory control in relation to nicotine addiction in contexts that differ in terms of reward. Methods: Participants filled out questionnaires and performed a go/no-go task with three conditions. In one condition, the stimuli were neutral color squares, and in the reward conditions, these were smoking-related pictures and money-related pictures, respectively. In total, 43 non-abstinent individuals that smoke and 35 individuals that do not smoke were included in the sample. Results: The main results showed that individuals that smoke, relative to individuals that do not smoke, had reduced inhibitory control in both reward contexts, relative to a neutral context. The reductions in inhibitory control were mirrored by speeded responses. Conclusions: Individuals that smoke seem to present with reduced inhibitory control, which is most pronounced in contexts of reward. Consistent with incentive sensitization theory, the reduced inhibitory control may be (at least partly) due to the heightened approach bias to reward-related stimuli as indicated by the speeded responses.

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Prevalence rates of Attention-Deficit/Hyperactivity Disorder (ADHD) differ with geographical areas varying in sunlight intensity. We here studied 1) annual variation in inattention at treatment initiation; 2) annual variation in response to ADHD treatment [Methylphenidate (MPH)] by day of treatment initiation; and 3) dose-dependency. We predicted least baseline inattention during a period of high sunlight intensity implying more room for improvement (i.e., a better treatment response) when sunlight intensity is low. These hypotheses were not confirmed. High dose treated patients however had significantly better attention than low dosed treated patients, only when treated in the period from winter to summer solstice. Change in solar irradiance (SI) during treatment period was negatively related to attentional improvement. The above described findings were primarily found in inattention ratings and replicated in omission errors on a Continuous Performance Task. Daylight and inattention have been proposed to be related via mediation of the circadian system. One mechanism of MPH may be to enhance sensitivity to the diurnal entrainment to sunlight and the question can be raised whether appropriate lighting could potentiate the effects of stimulants.

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