100 days of Adolescence: Elucidating Externalizing Behaviors Through the Daily Assessment of Inhibitory Control.

Inhibitory control is a transdiagnostic risk factor for externalizing behaviors, particularly during adolescence. Despite advances in understanding links between inhibitory control and externalizing behaviors across youth on average, significant questions remain about how these links play out in the day-to-day lives of individual adolescents. The goals of the current study were to: (1) validate a novel 100-occasion measure of inhibitory control; (2) assess links between day-to-day fluctuations in inhibitory control and individual differences in externalizing behaviors; and (3) illustrate the potential of intensive longitudinal studies for person-specific analyses of adolescent externalizing behaviors. Participants were 106 youth (57.5% female, Mage = 13.34 years; SDage = 1.92) who completed a virtual baseline session followed by 100 daily surveys, including an adapted Stroop Color Word task designed to assess inhibitory control. Results suggested that the novel task was generally reliable and valid, and that inhibitory control fluctuated across days in ways that were meaningfully associated with individual differences in baseline impulsive behaviors. Results of illustrative personalized analyses suggested that inhibitory control had more influence in the daily networks of adolescents who used substances during the 100 days than in a matched set of adolescents who did not. This work marks a path forward in intensive longitudinal research by validating a novel inhibitory control measure, revealing that daily fluctuations in inhibitory control may be a unique construct broadly relevant to adolescent externalizing problems, and at the same time, highlighting that links between daily inhibitory control and impulsive behaviors are adolescent-specific.

fNIRS correlates of the development of inhibitory control in young obese subjects.

Executive functions are closely related to the prefrontal cortex, and inhibitory control is an important component of executive functioning. Previous studies have found that inhibitory control continues to develop after adolescence and that obesity is associated with executive functions. However, few studies have addressed whether obesity affects the development of inhibitory control. Hence, we focused on whether inhibitory control continues to develop after adolescence in obese individuals. We used a Stroop task to measure the inhibitory control of young obese subjects, and monitored accompanying brain activation by functional near-infrared spectroscopy technology. The findings suggest that brain activation due to Stroop interference does not increase with age in obese subjects and that early prevention of executive function deficit is recommended.

Computational Psychometrics Using Psychophysiological Measures for the Assessment of Acute Mental Stress.

The goal of this study was to provide reliable quantitative analyses of psycho-physiological measures during acute mental stress. Acute, time-limited stressors are used extensively as experimental stimuli in psychophysiological research. In particular, the Stroop Color Word Task and the Arithmetical Task have been widely used in several settings as effective mental stressors. We collected psychophysiological data on blood volume pulse, thoracic respiration, and skin conductance from 60 participants at rest and during stressful situations. Subsequently, we used statistical univariate tests and multivariate computational approaches to conduct comprehensive studies on the discriminative properties of each condition in relation to psychophysiological correlates. The results showed evidence of a greater discrimination capability of the Arithmetical Task compared to the Stroop test. The best predictors were the short time Heart Rate Variability (HRV) indices, in particular, the Respiratory Sinus Arrhythmia index, which in turn could be predicted by other HRV and respiratory indices in a hierarchical, multi-level regression analysis. Thus, computational psychometrics analyses proved to be an effective tool for studying such complex variables. They could represent the first step in developing complex platforms for the automatic detection of mental stress, which could improve the treatment.

Distinct patterns of blood oxygenation in the prefrontal cortex in clinical phenotypes of schizophrenia and bipolar disorder.

BACKGROUND: Schizophrenia (SZ) and bipolar disorder (BD) are characterized by different clinical symptoms, and have previously been considered as categorically separate. However, several lines of evidence controversially suggest that these two disorders may run on a continuum. While it is therefore important to evaluate the subtle differences between SZ and BD, few studies have investigated the difference of brain functioning between the two by focusing on the common symptoms of cognitive functioning and impulsivity, rather than positive/negative and mood symptoms. Recent developments in near-infrared spectroscopy (NIRS) technology have enabled noninvasive assessment of brain function in people with psychiatric disorders. METHODS: Near-infrared spectroscopy (NIRS) using 24-channels was conducted during the verbal fluency task (VFT) and Stroop color-word task (SCWT) in 38 patients diagnosed with SZ, 34 patients with BD, and 26 age- and sex-matched healthy controls. RESULTS: Oxyhemoglobin changes in the prefrontal cortex (PFC) were significantly lower particularly in the SZ compared to control group during the VFT. On the other hand, these were significantly lower particularly in the BD and SZ group to control group during the SCWT. Regression analysis showed that hemodynamic changes were significantly correlated with verbal memory and impulsivity in both disorders. CONCLUSION: These findings suggest that different hemodynamic responses in the prefrontal cortex might reflect cognitive functioning and impulsivity, providing a greater insight into SZ and BD pathophysiology.

Reduced prefrontal hemodynamic response in adult attention-deficit hyperactivity disorder as measured by near-infrared spectroscopy.

AIM: Recent developments in near-infrared spectroscopy (NIRS) have enabled non-invasive clarification of brain functions in psychiatric disorders. In pediatric attention-deficit hyperactivity disorder (ADHD), reduced prefrontal hemodynamic responses have been observed with NIRS repeatedly. However, there are few studies of adult ADHD by multi-channel NIRS. Therefore, in this study, we used multi-channel NIRS to examine the characteristics of prefrontal hemodynamic responses during the Stroop Color-Word Task (SCWT) in adult ADHD patients and in age- and sex-matched control subjects. METHODS: Twelve treatment-naïve adults with ADHD and 12 age- and sex-matched healthy control subjects participated in the present study after giving consent. We used 24-channel NIRS to measure the oxygenated hemoglobin (oxy-Hb) changes at the frontal lobes of participants during the SCWT. We compared the oxy-Hb changes between adults with ADHD and control subjects by t-tests with Bonferroni correction. RESULTS: During the SCWT, the oxy-Hb changes observed in the ADHD group were significantly smaller than those in the control group in channels 11, 16, 18, 21, 22, 23, and 24, corresponding to the prefrontal cortex. At channels 16, 21, 23, and 24 of the ADHD group, there were negative correlations between the symptomatic severity and the oxy-Hb changes. CONCLUSION: The present study suggests that adults with ADHD have reduced prefrontal hemodynamic response as measured by NIRS.

Attentional bias towards sleep-related stimuli in insomnia disorder: a behavioural and ERP study.

Many studies have used behavioural experiments to show an attentional bias towards sleep-related stimuli in people with insomnia disorder. A measurement of event-related potential is needed to investigate the cognitive processing mechanism of the attentional process. The present study used the emotional Stroop paradigm and event-related potentials to measure attentional bias towards sleep-negative, sleep-positive and sleep-unrelated neutral words. The study comprised 16 participants with insomnia disorder and 15 participants who were good sleepers. Behavioural data indicated that there was a significant interference effect of sleep-positive words between the insomnia group and the good sleepers, and a marginally significant interference effect from sleep-negative words between groups. In the insomnia group, event-related potential data showed that sleep-negative words elicited higher amplitudes of P1 and N1 components than did sleep-positive and sleep-unrelated words. Our results provide evidence for the early cognitive processing of sleep-negative stimuli, which suggests that the psychological treatment of insomnia could benefit from addressing early hypervigilance towards these stimuli.

Persistence of impulsivity in pediatric and adolescent patients with obsessive-compulsive disorder.

AIM: Increasing clinical evidence points to impulsivity as a symptom of obsessive-compulsive disorder (OCD). However, little is known about its persistence over time. METHODS: In this study, we evaluated the performance of 12 pediatric patients with OCD on the Stroop color-word task, which assesses impulsivity, and compared this with age- and sex-matched controls. In parallel, we measured changes in hemodynamic responses during the task, using near-infrared spectroscopy. As patients in the OCD group were naïve to treatment, we compared results before and after 3-year medication with serotonin reuptake inhibitors. RESULTS: We report that, compared with controls, the OCD group had significantly poorer performance and less activation in the prefrontal cortex during the Stroop color-word task. Surprisingly, while serotonin-reuptake-inhibitors treatment reduced OCD symptomology, it did not improve the diminished hemodynamic responses or task performance of these patients. CONCLUSION: Our findings suggest that a persistent deficit exists in the inhibitory control of pediatric patients with OCD; they also provide insight into the pathophysiology of OCD.