Impulsiveness and executive control of working memory

Healthy dietary choices involve prefrontal mechanisms associated with long-term reward maximization but not working memory

Taste and health are critical factors to be considered when choosing foods. Prioritizing healthiness over tastiness requires self-control. It has also been suggested that self-control is guided by cognitive control. We then hypothesized that neural mechanisms underlying healthy food choice are associated with both self-control and cognitive control. Human participants performed a food choice task and a working memory task during functional MRI scanning. Their degree of self-control was assessed behaviorally by the value discount of delayed monetary rewards in intertemporal choice. Prioritizing healthiness in food choice was associated with greater activity in the superior, dorsolateral, and medial prefrontal cortices. Importantly, the prefrontal activity was greater in individuals with smaller delay discounting (i.e. high self-control) who preferred a delayed larger reward to an immediate smaller reward in intertemporal choice. On the other hand, working memory activity did not show a correlation with delay discounting or food choice activity, which was further supported by supplementary results that analyzed data from the Human Connectome Project. Our results suggest that the prefrontal cortex plays a critical role in healthy food choice, which requires self-control, but not working memory, for maximization of reward attainments in a remote future.

Neurocircuitry of Personality Traits and Intent in Decision-Making

Even though most personality features are moderately stable throughout life, changes can be observed, which influence one's behavioral patterns. A variety of subjective assessments can be performed to track these changes; however, the subjective characteristic of these assessments may lead to questions about intentions and values. The use of neuroimaging techniques may aid the investigation of personality traits through a more objective lens, overcoming the barriers imposed by confounders. Here, neurocircuits associated with changes in personality domains were investigated to address this issue. Cortical systems involved in traits such as extraversion and neuroticism were found to share multiple components, as did traits of agreeableness and conscientiousness, with these four features revolving around the activation and structural integrity of the medial prefrontal cortex (mPFC). The attribute of openness appears scattered throughout cortical and subcortical regions, being discussed here as a possible reflection of intent, at the same time modulating and being governed by other traits. Insights on how systems operate on personality may increase comprehension on factors acting on the evolution, development, and consolidation of personality traits through life, as in neurocognitive disorders.

Validity and Reliability of a Revised S-UPPS-P Impulsive Behavior Scale: The Interplay between Impulsivity and Working Memory

Impulsivity is a multidimensional construct. The UPPS-P model of impulsivity differentiates five distinct dimensions: negative urgency, positive urgency, lack of premeditation, lack of perseverance, and sensation seeking. The present study, reports the first translation and validation of the recently revised short form of the UPPS-P scale (S-UPPS-P) on a Persian-speaking sample, examining the relationship between impulsivity and working memory. who also completed the Positive and Negative Affect Scale (PANAS), the Buss and Perry Aggression Questionnaire, the Behavioral Inhibition and Activation Scales (BIS/BAS), and the Wechsler Digit Span Task (WDST). A series of confirmatory factor analyses, and Cronbach's alpha results supported the factor structure of the scale. The findings supported the S-UPPS-P model's hypothesized correlations with PANAS, aggressiveness, and the construct validity of the model. The results of hierarchical regression analysis showed that backward and forward digit span scores of the WDST predicted the S-UPPS-P impulsivity scores over the portion explained by BIS/BAS, PANAS, and aggression scores. To conclude, the revised S-UPPS-P Impulsive Behavior Scale was well supported even in a very different population than usually sampled, adding to growing evidence that it assesses distinct but interrelated aspects of the impulsivity construct. Our findings also suggest that attentional capacities and working memory play important roles in the prediction of impulsivity.

Impulsivity Relates to Multi-Trial Choice Strategy in Probabilistic Reversal Learning

Impulsivity is defined as a trait-like tendency to engage in rash actions that are poorly thought out or expressed in an untimely manner. Previous research has found that impulsivity relates to deficits in decision making, in particular when it necessitates executive control or reward outcomes. Reinforcement learning (RL) relies on the ability to integrate reward or punishment outcomes to make good decisions, and has recently been shown to often recruit executive function; as such, it is unsurprising that impulsivity has been studied in the context of RL. However, how impulsivity relates to the mechanisms of RL remains unclear. We aimed to investigate the relationship between impulsivity and learning in a reward-driven learning task with probabilistic feedback and reversal known to recruit executive function. Based on prior literature in clinical populations, we predicted that higher impulsivity would be associated with poorer performance on the task, driven by more frequent switching following unrewarded outcomes. Our results did not support this prediction, but more advanced, trial-history dependent analyses revealed specific effects of impulsivity on switching behavior following consecutive unrewarded trials. Computational modeling captured group-level behavior, but not impulsivity results. Our results support previous findings highlighting the importance of sensitivity to negative outcomes in understanding how impulsivity relates to learning, but indicate that this may stem from more complex strategies than usually considered in computational models of learning. This should be an important target for future research.

The Facilitative Effect of Impulsiveness on The Dark Triad and Social Network Sites Addiction

This research investigated the relationships of the Dark Triad, impulsiveness, and social network sites (SNS) addiction with adolescents. In particular, this research examined the indirect effects of the measured motor, attentional, and nonplanning impulsiveness on the relationship of the Dark Triad and SNS addiction. To examine the possible antecedents of SNS addiction, 169 adolescents aged 14-17 were recruited for this research. After obtaining informed consents from their legal guardians, these adolescents completed the Dirty Dozen, the modified Bergen Facebook Addiction Scale, and the Barratt Impulsiveness Scale – version 11. Results showed that the Dark Triad composite score was positively correlated with SNS addiction and the different aspects of impulsiveness, while SNS addiction was positively correlated with motor impulsiveness. The indirect effect of motor impulsiveness on the relationship of the Dark Triad and SNS addiction was significant. The present findings provide theoretical insights to the development of SNS addiction.

Working Memory Depletion Affects Intertemporal Choice Among Internet Addicts and Healthy Controls

Addiction to the Internet has emerged as a new kind of addictive behavior. Although previous studies have revealed that impairments in working memory led to suboptimal decision making (e.g., a greater willingness to choose smaller, more immediate rewards), little is known about how working memory affects intertemporal choice in Internet addicts and normal users. Thus, this study’s aim was to investigate the effect of working memory task on intertemporal choice in 33 participants addicted to internet and 25 healthy controls. Participants were administered (a) a test for Internet Addiction, (b) a single delay discounting self-report questionnaire (c) a working memory task. Differences between the Internet addicts and the control group were observed in terms of delay discounting rates, reaction times, and in memory accuracy rates. We observed significantly higher delay discounting rates among individuals addicted to the Internet. Moreover, it was documented that reaction times follow the 4-level working memory condition were significantly longer than follow the 2-level condition, in both the Internet addicts and the control group. The current findings suggest that Internet addicts are more likely to make short-sighted decisions than normal Internet users. The higher the level of working memory, the more likely an individual is to choose the present smaller reward, thus making short-sighted decisions, and have longer response times.

Executive Function, Working Memory, and Verbal Fluency in Relation to Non-Verbal Intelligence in Greek-Speaking School-Age Children with Developmental Language Disorder

Developmental Language Disorder (DLD) is often associated with impairments in working memory (WM), executive functions (EF), and verbal fluency. Moreover, increasing evidence shows poorer performance of children with DLD on non-verbal intelligence tests relative to their typically developing (TD) peers. Yet, the degree and generality of relevant difficulties remain unclear. The present study aimed at investigating WM capacity, key EFs and verbal fluency in relation to non-verbal intelligence in Greek-speaking school-age children with DLD, compared to TD peers (8–9 years). To our knowledge, the present study is the first to attempt a systematic relevant assessment with Greek-speaking school-age children, complementing previous studies mostly involving English-speaking participants. The results showed that children with DLD scored lower than TD peers on the non-verbal intelligence measure. Groups did not differ in the inhibition measures obtained (tapping resistance to either distractor or proactive interference), but children with DLD were outperformed by TD peers in the WM capacity, updating, monitoring (mixing cost), and verbal fluency (phonological and semantic) measures. The effects showed limited (in the case of backward digit recall) or no dependence on non-verbal intelligence. Findings are discussed in terms of their theoretical and practical implications as well as in relation to future lines of research.

Relationship between impulsivity, comorbid anxiety and neurocognitive functions in bipolar disorder

OBJECTIVE

The aim of the study is to examine the relationship between anxiety and impulsivity and to reveal the correlation of these variables with clinical and sociodemographic features. It is also aimed to investigate the relationship between impulsivity and anxiety with neurocognitive functions in bipolar disorder.

METHODS

The sample of the study comprises of 71 patients with bipolar disorder type I without any comorbidity (BD), 37 patients with anxiety disorder comorbidity with bipolar disorder type I (BDAD), 52 patients with anxiety disorder (AD) and 50 healthy controls (HC). Participants completed Barratt Impulsivity Scale-11, State-Trait Anxiety Inventory 1-2, Panic Disorder Severity Scale (PDSS), brief version of Fear of Negative Evaluation Scale (FNES), Anxiety Sensitivity Index-3 (ASI-3), Trail-Making Test A-B, Digit Span Test, Stroop Test.

RESULTS

PDSS scores, trait anxiety level, hypomanic and mixed episode numbers explain 26% of attention impulsivity. Gender and ASI-3 social dimensions explain 16% of motor impulsivity. Trait anxiety explains non-planning and total impulsivity at 26 and 24%, respectively. When neurocognitive impairment's effect was controlled, it was found AD and BDAD groups had higher impulsivity levels than the BD and HC groups.

CONCLUSION

Anxiety disorder comorbidity increases impulsivity in bipolar disorder.KEYPOINTSIn the presence of anxiety disorder spectrum comorbidity, bipolar disorder patients will have increased impulsivity and the clinical course may be more severe.Trait anxiety levels and anxiety sensitivity may be predictive factors for impulsivity.In the presence of anxiety disorder spectrum comorbidity, it should be taken into consideration that these patients may be more impulsive and should be treated with more care in terms of evaluation of the disorder.

Conscientiousness mediates the link between brain structure and consideration of future consequence

The individual difference in valuing immediate and future outcomes is referred to as consideration of future consequences (CFC, including CFC-Future [CFC-F] and CFC-Immediate [CFC-I]), which significantly influences daily behaviour. Although CFC is believed to be affected by brain features and personalities, the relational model of brain correlates, personalities and CFC has yet to be determined. This study was designed to explore the brain structure related to CFC-F and CFC-I and the mediating role of conscientiousness. We adopted a voxel-based morphometry study and used grey matter density (GMD) as an indication of brain structure. The results showed that GMD in the ventromedial prefrontal cortex (VMPFC) was positively associated with CFC-F; however, we did not find relevant regions affecting CFC-I. Furthermore, conscientiousness was found to mediate the relationship between GMD in the VMPFC and CFC-F. This study provides initial evidence concerning the neural basis of CFC-F and argues that the features of brain structure could be associated with CFC-F through related high-order personality traits. Additionally, the distinction between CFC-F and CFC-I may be based on differences in brain structure.

Self-reported and neurocognitive impulsivity in obsessive-compulsive disorder

BACKGROUND

Although a behavioural addiction model of obsessive-compulsive disorder (OCD) has been proposed, it is still unclear if and how self-report and neurocognitive measures of impulsivity (such as risk-taking-, reflection- and motor-impulsivities) are impaired and/or inter-related in this particular clinical population.

METHODS

Seventeen OCD patients and 17 age-, gender-, education- and IQ-matched controls completed the Barratt Impulsivity Scale, the Obsessive-Compulsive Inventory-Revised, and the Beck Depression Inventory and were evaluated with the Yale-Brown Obsessive-Compulsive Scale and three computerized paradigms including reward (the Cambridge Gambling Task), reflection (the Information Sampling Task) and motor impulsivity (Stop Signal Task).

RESULTS

Despite not differing from healthy controls in any neurocognitive impulsivity domain, OCD patients demonstrated increased impulsivity in a self-report measure (particularly attentional impulsivity). Further, attentional impulsivity was predicted by severity of obsessive-compulsive symptoms.

CONCLUSIONS

Our findings suggest that OCD is characterized by a subjective (rather than objective) impulsivity; in addition, self-reported impulsivity was largely determined by severity of OCD symptoms.

Which features of psychopathy and impulsivity matter most for prison violence? New evidence among female prisoners

Prison violence is a complex and multifaceted phenomenon. While a great deal of research has been conducted in male samples, very few studies are dedicated to understanding violence committed by female offenders. Two constructs that have emerged as important predictors of violence are psychopathy and impulsivity. These constructs may be an important line of inquiry due to the close association between psychopathy, impulsivity, and violence. In a sample of 166 female offenders, we used the 3-facet model of psychopathy and 3-factor model of trait impulsivity with the goal to statistically explain two types of prison violence: official reports of violent misconducts over a 12-month period, and self-report of deliberately instigating a violent altercation. We conducted three separate regression models to test the independent contribution of psychopathy and impulsivity, as well as accounting for the overlap between psychopathy and impulsivity. When impulsivity and psychopathy were not competing within the same model, affective and behavioral psychopathic traits, and nonplanning impulsiveness predicted violent misconducts. However, when accounting for impulsivity and psychopathy within the same model, only affective psychopathic traits remained significant. When predicting if an offender deliberately started a violent altercation, separate statistical models showed affective and interpersonal psychopathic traits, and nonplanning impulsiveness were significant. When competing for variance within the same statistical model, only affective and interpersonal psychopathic traits remained as significant predictors. This suggests an overlap between psychopathic traits and nonplanning impulsivity when understanding violent misconducts in female offenders, while affective psychopathic explains female prison violence, regardless of impulsivity.

Mediational Pathways Among Trait Impulsivity, Heroin-use Consequences, and Current Mood State

BACKGROUND

This study examined whether lifetime heroin-use consequences mediate the relationship between trait impulsivity and three current mood outcomes: depression symptoms, stress levels, and perception of life events.

METHOD

Regular heroin users (N = 163) were assessed using the Barratt Impulsiveness Scale (BIS-11) to measure trait impulsivity; a standardized Drug History and Use Questionnaire to measure lifetime adverse consequences of heroin use; Beck Depression Inventory II to measure current depression symptoms; Stress subscale of the Depression Anxiety Stress scale; and Hassles and Uplifts scale to measure perception of life events.

RESULTS

BIS-11 Attentional and Motor impulsivity were positively related to number of adverse heroin-use consequences, depression symptoms, and stress level, and negatively associated with positive perception of events. A greater number of heroin-use consequences was related to more depression symptoms, higher stress, more negative perception of events, injection heroin use, and earlier ages of first and regular heroin use. In six mediation models, lifetime heroin-use consequences partially mediated relationships between two trait impulsivity domains (Attentional, Motor) and current mood measures (depression symptoms, stress, perception of events).

CONCLUSIONS

The present findings suggest that current negative mood can be a response to the accumulated burden of heroin-use consequences, particularly in the presence of high trait impulsivity.

Validation of the Portuguese Version of Impulsive-Premeditated Aggression Scale in an Inmate Population

Aggression is one of the core symptoms of antisocial personality disorder (ASPD) with therapeutic and prognostic relevance. ASPD is highly prevalent among inmates, being responsible for adverse events and elevated direct and indirect economic costs for the criminal justice system. The Impulsive/Premeditated Aggression Scale (IPAS) is a self-report instrument that characterizes aggression as either predominately impulsive or premeditated. This study aims to determine the validity and reliability of the IPAS in a sample of Portuguese inmates. A total of 240 inmates were included in the study. A principal component factor analysis was performed so as to obtain the construct validity of the IPAS impulsive aggression (IA) and premeditated aggression (PM) subscales; internal consistency was determined by Cronbach's alpha coefficient; convergent and divergent validity of the subscales were determined analyzing correlations with the Barratt Impulsiveness scale, 11th version (BIS-11), and the Psychopathic Checklist Revised (PCL-R). The rotated matrix with two factors accounted for 49.9% of total variance. IA subscale had 11 items and PM subscale had 10 items. The IA and PM subscales had a good Cronbach's alpha values of 0.89 and 0.88, respectively. The IA subscale is correlated with BIS-11 attentional, motor, and non-planning impulsiveness dimensions (p < 0.05). The PM subscale is correlated with BIS-11 attentional, motor impulsiveness dimensions (p < 0.05). The PM subscale is correlated with PCL-R interpersonal, lifestyle, and antisocial dimensions (p < 0.05). The IA subscale is not correlated with PCL-R. The Portuguese translated version of IPAS has adequate psychometric properties, allowing the measurement of impulsive and premeditated dimensions of aggression.

Individual Differences in Frequency of Inner Speech: Differential Relations with Cognitive and Non-cognitive Factors

Inner speech plays a crucial role in behavioral regulation and the use of inner speech is very common among adults. However, less is known about individual differences in the frequency of inner speech use and about the underlying processes that may explain why people exhibit individual differences in the frequency of inner speech use. This study was conducted to investigate how individual differences in the frequency of inner speech use are related to cognitive and non-cognitive factors. Four functions of inner speech including self-criticism, self-reinforcement, self-management, and social assessment measured by an adapted version of Brinthaupt's Self-Talk Scale were examined. The cognitive factors that were considered included executive functioning and complex reasoning and the non-cognitive factors consisted of trait anxiety and impulsivity. Data were collected from a large Chinese sample. Results revealed that anxiety and impulsivity were mainly related to the frequency of the affective function of inner speech (self-criticism and self-reinforcement) and executive functions and complex reasoning were mainly related to the frequency of the cognitive, self-regulatory function of inner speech (self-management).

Relationships between Dimensions of Impulsivity and Prospective Memory

Prospective memory refers to the ability to plan and execute future intentions. A burgeoning body of research indicates that a significant proportion of the variability in prospective memory performance can be accounted for by personality traits, with two recent studies revealing that the various dimensions of impulsivity measured by the Barratt Impulsivity Scale–11 (BIS–11) are related to prospective memory failures. The present study was conducted to examine which dimensions of impulsivity indexed by the BIS–11 and UPPS–P relate to prospective memory failures and which dimensions of impulsivity contribute unique variance in the prediction of prospective memory failures. A large sample ( N = 662) of students completed the BIS–11, UPPS–P, Prospective Memory Questionnaire and a habitual prospective memory test. Consistent correlations between six of the seven measures of impulsivity and prospective memory failures were found. Regression analyses further revealed that lack of perseverance, emotional urgency and attentional impulsivity were reliable and unique predictors of prospective memory failures. Thus, difficulty remaining focused on tasks (especially long, boring or difficult tasks); lack of forethought, planning and distaste for challenging tasks; and tendencies to behave impulsively under conditions of strong affect relate most strongly to prospective memory failures. Copyright © 2015 European Association of Personality Psychology

Quick to Act, Quick to Forget: The Link between Impulsiveness and Prospective Memory

Several traits of impulsiveness (e.g. lack of planning and perseverance, difficulty focusing attention) seem intimately connected to the skills required for successful prospective memory performance. This is the first study to examine whether the various inter–correlated dimensions of impulsiveness are related to problems with prospective memory. Undergraduate students (N = 184) completed the Barratt Impulsiveness Scale 11, the Prospective Memory Questionnaire, the Prospective and Retrospective Memory Questionnaire, and two objective prospective memory tests. Results revealed consistent correlations between the various dimensions of impulsiveness (attentional, motor, non–planning) and self–reported problems with prospective memory. Subsequent regression analyses indicated that attentional impulsiveness is a unique predictor of self–reported problems with internally cued prospective memory, and non–planning impulsiveness is a unique predictor of self–reported problems with episodic and overall prospective memory. Similarly, findings from the objective prospective tests showed that non–planning impulsiveness was related to worse performance on the two prospective memory tests. Whereas non–planning impulsiveness was also related to using fewer prospective memory–aiding strategies, mediation analyses showed that use of these strategies does not account for any of the detected relationships. Because the findings suggest that a failure to plan does not underlie the detected effects, other potential explanations for the relationships are discussed. Copyright © 2013 European Association of Personality Psychology

Sleep problems across development: a pathway to adolescent risk taking through working memory

Problematic sleep can be detrimental to the development of important cognitive functions, such as working memory, and may have the potential for negative behavioral consequences, such as risk-taking. In this way, sleep problems may be particularly harmful for youth-whose cognitive abilities are still developing and who are more susceptible to risky behavior. Using data from a large, national, longitudinal study, continuity and change in sleep problems were examined from 2 to 15 years of age and associated with deficits in working memory at age 15 and risk taking behaviors at age 18. Participants (N = 1,364 children; 48.3% female) were assessed for sleep problems (parent-report), working memory (behavioral task), and risk taking behavior (youth self-report). The sample was predominantly White (80.4%); additional races represented in the sample included Black/African American (12.9%), Asian/Pacific Islander (1.6%), American Indian/Eskimo/Aleut (.4%), and Other (4.7%). The findings suggest that sleep problems are likely to cascade across development, with sleep problems demonstrating continuity from infancy to early childhood, early childhood to middle childhood, and middle childhood to adolescence. Although sleep problems in infancy, early childhood, and middle childhood were not directly related to adolescent working memory, sleep problems during adolescence were associated with poorer adolescent working memory. In turn, these deficits in working memory were related to greater risk taking in late adolescence. In summary, the present results suggest that sleep problems in earlier periods are indicative of risk for sleep problems later in development, but that sleep problems in adolescence contribute uniquely to deficits in working memory that, in turn, lead to risky behavior during late adolescence.

Dopamine D(2/3) receptor availability and human cognitive impulsivity: a high-resolution positron emission tomography imaging study with [¹¹C]raclopride

OBJECTIVE

Human impulsivity is a complex multidimensional construct encompassing cognitive, emotional, and behavioural aspects. Previous animal studies have suggested that striatal dopamine receptors play a critical role in impulsivity. In this study, we investigated the relationship between self-reported impulsiveness and dopamine D(2/3) receptor availability in striatal subdivisions in healthy subjects using high-resolution positron emission tomography (PET) with [11C]raclopride.

METHODS

Twenty-one participants completed 3-T magnetic resonance imaging and high-resolution PET scans with [11C]raclopride. The trait of impulsiveness was measured using the Barratt Impulsiveness Scale (BIS-11). Partial correlation analysis was performed between BIS-11 scores and D(2/3) receptor availability in striatal subregions, controlling for the confounding effects of temperament characteristics that are conceptually or empirically related to dopamine, which were measured by the Temperament and Character Inventory.

RESULTS

The analysis revealed that the non-planning (p = 0.004) and attentional (p = 0.007) impulsiveness subscale scores on the BIS-11 had significant positive correlations with D(2/3) receptor availability in the pre-commissural dorsal caudate. There was a tendency towards positive correlation between non-planning impulsiveness score and D(2/3) receptor availability in the post-commissural caudate.

CONCLUSION

These results suggest that cognitive subtrait of impulsivity is associated with D(2/3) receptor availability in the associative striatum that plays a critical role in cognitive processes involving attention to detail, judgement of alternative outcomes, and inhibitory control.

Executive functions in borderline personality disorder

Different domains of executive function such as working memory and response inhibition were investigated together with elementary cognitive processes in borderline personality disorder (BPD). Patients with BPD (N=28) were compared to nonpatient controls (NP, N=28) on eight tasks (e.g. n-back, Go/NoGo, CPT-AX). In order to separate impairments in different cognitive domains and to assess the influence of more elementary cognitive processes on executive functioning, tasks were embedded in a reaction-time-decomposition approach. BPD patients solved tasks with accuracies comparable to those of nonpatients. The only exception was the n-back task, for which working memory is required: here, error rates were higher and increased more prominently in BPD patients depending on working memory load. In most tasks, movement times were shorter for BPD patients than for nonpatients, while the quality of task-solving was comparable. The faster processing in the BPD group was observable starting with the simplest task, i.e. a simple reaction-time task. These findings suggest that domains of executive functioning are differentially affected in BPD. In contrast to load-dependent deficits in working memory, response inhibition processes were unimpaired. Faster action-related processes could be observed in BPD patients in a variety of tasks; however, these did not influence executive functioning.

Cortical thickness of superior frontal cortex predicts impulsiveness and perceptual reasoning in adolescence

Impulsiveness is a pivotal personality trait representing a core domain in all major personality inventories. Recently, impulsiveness has been identified as an important modulator of cognitive processing, particularly in tasks that require the processing of large amounts of information. Although brain imaging studies have implicated the prefrontal cortex to be a common underlying representation of impulsiveness and related cognitive functioning, to date a fine-grain and detailed morphometric analysis has not been carried out. On the basis of ahigh-resolution magnetic resonance scans acquired in 1620 healthy adolescents (IMAGEN), the individual cortical thickness (CT) was estimated. Correlations between Cloninger's impulsiveness and CT were studied in an entire cortex analysis. The cluster identified was tested for associations with performance in perceptual reasoning tasks of the Wechsler Intelligence Scale for Children (WISC IV). We observed a significant inverse correlation between trait impulsiveness and CT of the left superior frontal cortex (SFC; Monte Carlo Simulation P<0.01). CT within this cluster correlated with perceptual reasoning scores (Bonferroni corrected) of the WISC IV. On the basis of a large sample of adolescents, we identified an extended area in the SFC as a correlate of impulsiveness, which appears to be in line with the trait character of this prominent personality facet. The association of SFC thickness with perceptual reasoning argues for a common neurobiological basis of personality and specific cognitive domains comprising attention, spatial reasoning and response selection. The results may facilitate the understanding of the role of impulsiveness in several psychiatric disorders associated with prefrontal dysfunctions and cognitive deficits.

Working memory ability predicts trajectories of early alcohol use in adolescents: the mediational role of impulsivity

AIMS

(i) To evaluate the role of pre-existing weakness in working memory ability (WM) as a risk factor for early alcohol use as mediated by different forms of impulsivity and (ii) to assess the adverse effects of progressive alcohol use on variations in WM over time.

DESIGN, SETTING AND PARTICIPANTS

A community sample of 358 adolescents [48% males, mean(age) (baseline) = 11.4 ± 0.87 years] from a longitudinal cohort design, assessed annually over 4 consecutive years with less than 6% attrition.

MEASUREMENTS

Repeated assessments were conducted for the following key variables: WM (based on performance on four separate tasks), frequency of alcohol use (AU) and three forms of impulsivity, namely sensation seeking (SS), acting without thinking (AWT) and delay discounting (DD). Latent growth curve modeling procedures were used to identify individual trajectories of change for all key variables.

FINDINGS

Weakness in WM (at baseline) predicted significantly both concurrent alcohol use and increased frequency of use over the four waves (P < 0.05). This effect was entirely mediated by two forms of impulsivity, AWT and DD, both of which were characterized by underlying weakness in WM. No individual variation was observed in the slopes of WM, which suggests that individual variations in alcohol use were not associated with changes in WM in our early adolescent sample.

CONCLUSIONS

Early adolescent alcohol use may be a consequence of (pre-existing) weaknesses in working memory (WM) rather than a cause of it. Efforts to reduce early alcohol use should consider the distinct roles of different impulsivity dimensions, in addition to WM, as potential targets of intervention.

Association of the COMT Met¹⁵⁸ allele with trait impulsivity in healthy young adults

Dopamine (DA) is considered to be an important neurotransmitter in the control of impulsive behavior, however, its underlying mechanisms have not been fully elucidated. Catechol-O-methyltransferase (COMT) is a key enzyme in the catabolism of DA within the prefrontal cortex (PFC) and has been suggested to play a role in the mediation of impulsive behavior. The COMT single nucleotide polymorphism (SNP) rs4680 (Val158Met) Met allele has been shown to decrease COMT enzyme activity and is associated with improved PFC cognitive function (intelligence and executive functions). Studies have associated the rs4680 genotype with impulsivity as a symptom in attention deficit hyperactivity disorder and substance abuse. However, only a few studies have assessed the effects of rs4680 on impulsiveness in healthy subjects, the results of which remain controversial. The Barratt Impulsiveness Scale (BIS-11) was applied to 82 healthy volunteers (including 42 females) who were genotyped for COMT rs4680. Subjects carrying the Met/Met genotype scored higher for the BIS-11 second-order factor Non-planning than carriers of the Val/Val genotype. No interaction between gender genotype was detected. Age, gender and education had no effect on the results. The COMT rs4680 Met/Met genotype was associated with higher impulsivity on the BIS-11 second-order factor Non-planning. These results suggest that COMT enzyme activity may be important in the regulation of impulsiveness among young adults. Further studies involving larger samples should be conducted to confirm the results of the present study.

Who multi-tasks and why? Multi-tasking ability, perceived multi-tasking ability, impulsivity, and sensation seeking

The present study examined the relationship between personality and individual differences in multi-tasking ability. Participants enrolled at the University of Utah completed measures of multi-tasking activity, perceived multi-tasking ability, impulsivity, and sensation seeking. In addition, they performed the Operation Span in order to assess their executive control and actual multi-tasking ability. The findings indicate that the persons who are most capable of multi-tasking effectively are not the persons who are most likely to engage in multiple tasks simultaneously. To the contrary, multi-tasking activity as measured by the Media Multitasking Inventory and self-reported cell phone usage while driving were negatively correlated with actual multi-tasking ability. Multi-tasking was positively correlated with participants’ perceived ability to multi-task ability which was found to be significantly inflated. Participants with a strong approach orientation and a weak avoidance orientation – high levels of impulsivity and sensation seeking – reported greater multi-tasking behavior. Finally, the findings suggest that people often engage in multi-tasking because they are less able to block out distractions and focus on a singular task. Participants with less executive control - low scorers on the Operation Span task and persons high in impulsivity - tended to report higher levels of multi-tasking activity.

Deconstructing and reconstructing cognitive performance in sleep deprivation

Mitigation of cognitive impairment due to sleep deprivation in operational settings is critical for safety and productivity. Achievements in this area are hampered by limited knowledge about the effects of sleep loss on actual job tasks. Sleep deprivation has different effects on different cognitive performance tasks, but the mechanisms behind this task-specificity are poorly understood. In this context it is important to recognize that cognitive performance is not a unitary process, but involves a number of component processes. There is emerging evidence that these component processes are differentially affected by sleep loss. Experiments have been conducted to decompose sleep-deprived performance into underlying cognitive processes using cognitive-behavioral, neuroimaging and cognitive modeling techniques. Furthermore, computational modeling in cognitive architectures has been employed to simulate sleep-deprived cognitive performance on the basis of the constituent cognitive processes. These efforts are beginning to enable quantitative prediction of the effects of sleep deprivation across different task contexts. This paper reviews a rapidly evolving area of research, and outlines a theoretical framework in which the effects of sleep loss on cognition may be understood from the deficits in the underlying neurobiology to the applied consequences in real-world job tasks.

The synergy of working memory and inhibitory control: behavioral, pharmacological and neural functional evidences

Concomitant deficits in working memory and behavioral inhibition in several psychiatric disorders like attention-deficit/hyperactivity disorder, addiction or mania, suggest that common brain mechanisms may underlie their etiologies. Based on the theoretical assumption that a continuum exists between health and mental disorders, we explored the relationship between working memory and inhibition in healthy individuals, through spontaneous inter individual differences in behavior, and tested the hypothesis of a functional link through the fronto-striatal dopaminergic system. Rats were classified into three groups, showing good, intermediate and poor working memory and were compared for their inhibitory abilities. These two functions were simultaneously modulated by a dose-effect of d-amphetamine and in situ hybridization was used to quantify dopaminergic receptor (RD1) mRNAs in prefrontal cortex and striatal areas. A functional relationship between working memory and inhibition abilities was revealed. Both functions were similarly modulated by d-amphetamine according to an inverted-U shaped relationship and depending on initial individual performances. D-amphetamine selectively improved working memory and inhibition of poor and intermediate performers at low doses whereas it impaired both processes in good performers at a higher dose. D1 receptors were less expressed in prelimbic, infralimbic and anterior cingulate cortices of good compared to intermediate and poor performers, whereas no difference was observed between groups in striatal areas. The synergy of working memory and inhibitory abilities, observed in both healthy and psychiatric populations, may originate from endogenous variability in dopaminergic prefrontal cortex activity. Such findings confirm the validity of a dimensional approach, based on the concept of continuity between health and mental disorders for identifying endophenotypes of mental disorders.

Common structural correlates of trait impulsiveness and perceptual reasoning in adolescence

BACKGROUND

Trait impulsiveness is a potential factor that predicts both substance use and certain psychiatric disorders. This study investigates whether there are common structural cerebral correlates of trait impulsiveness and cognitive functioning in a large sample of healthy adolescents from the IMAGEN project.

METHODS

Clusters of gray matter (GM) volume associated with trait impulsiveness, Cloningers' revised temperament, and character inventory impulsiveness (TCI-R-I) were identified in a whole brain analysis using optimized voxel-based morphometry in 115 healthy 14-year-olds. The clusters were tested for correlations with performance on the nonverbal tests (Block Design, BD; Matrix Reasoning, MT) of the Wechsler Scale of Intelligence for Children IV reflecting perceptual reasoning.

RESULTS

Cloningers' impulsiveness (TCI-R-I) score was significantly inversely associated with GM volume in left orbitofrontal cortex (OFC). Frontal clusters found were positively correlated with performance in perceptual reasoning tasks (Bonferroni corrected). No significant correlations between TCI-R-I and perceptual reasoning were observed.

CONCLUSIONS

The neural correlate of trait impulsiveness in the OFC matches an area where brain function has previously been related to inhibitory control. Additionally, orbitofrontal GM volume was associated with scores for perceptual reasoning. The data show for the first time structural correlates of both cognitive functioning and impulsiveness in healthy adolescent subjects.

Impaired goal-directed behavioural control in human impulsivity

Two dissociable learning processes underlie instrumental behaviour. Whereas goal-directed behaviour is controlled by knowledge of the consequences, habitual behaviour is elicited directly by antecedent Pavlovian stimuli without knowledge of the consequences. Predominance of habitual control is thought to underlie psychopathological conditions associated with corticostriatal abnormalities, such as impulsivity and drug dependence. To explore this claim, smokers were assessed for nicotine dependence, impulsivity, and capacity for goal-directed control over instrumental performance in an outcome devaluation procedure. Reduced goal-directed control was selectively associated with the Motor Impulsivity factor of Barrett's Impulsivity Scale (BIS), which reflects propensity for action without thought. These data support the claim that human impulsivity is marked by impaired use of causal knowledge to make adaptive decisions. The predominance of habit learning may play a role in psychopathological conditions that are associated with trait impulsivity.

The prefrontal model revisited: double dissociations between young sleep deprived and elderly subjects on cognitive components of performance

STUDY OBJECTIVES

The prefrontal model suggests that total sleep deprivation (TSD) and healthy aging produce parallel cognitive deficits. Here we decompose global performance on two common tasks into component measures of specific cognitive processes to pinpoint the source of impairments in elderly and young TSD participants relative to young controls and to each other.

SETTING

The delayed letter recognition task (DLR) was performed in 3 studies. The psychomotor vigilance task (PVT) was performed in 1 of the DLR studies and 2 additional studies.

SUBJECTS

For DLR, young TSD (n=20, age=24.60 ± 0.62 years) and young control (n=17, age=24.00 ± 2.42); elderly (n=26, age=69.92 ± 1.06). For the PVT, young TSD (n=18, age=26.65 ± 4.57) and young control (n=16, age=25.19 ± 2.90); elderly (n=21, age=71.1 ± 4.92).

MEASUREMENTS AND RESULTS

Both elderly and young TSD subjects displayed impaired reaction time (RT), our measure of global performance, on both tasks relative to young controls. After decomposing global performance on the DLR, however, a double dissociation was observed as working memory scanning speed was impaired only in elderly subjects while other components of performance were impaired only by TSD. Similarly, for the PVT a second double dissociation was observed as vigilance impairments were present only in TSD while short-term response preparation effects were altered only in the elderly.

CONCLUSIONS

The similarity between TSD and the elderly in impaired performance was evident only when examining global RT. In contrast, when specific cognitive components were examined double dissociations were observed between TSD and elderly subjects. This demonstrates the heterogeneity in those cognitive processes impaired in TSD versus the elderly.

EEG oscillatory activity associated to monetary gain and loss signals in a learning task: effects of attentional impulsivity and learning ability

This study investigated the influence of individual differences in attentional impulsivity (Att-Imp), learning ability, and learning practice on oscillatory activity and phase synchrony responses to monetary gain and loss signals during an instrumental-learning task in healthy women. We used a trial-by-trial wavelet-based time-frequency analysis of the electroencephalographic (EEG) signal to provide amplitude and inter-site phase synchrony measures from 30 electrodes in theta (4-8 Hz, 350-500 ms), alpha (8-12 Hz, 100-200 ms), beta (13-25 Hz, 100-200 ms), and gamma (30-40 Hz, 350-450 ms) time-frequency ranges. Oscillatory amplitude and inter-site phase synchrony were both greater following loss signals as compared to gain signals in theta, beta, and gamma frequency bands. Low Att-Imp subjects had higher theta activity within a 350-500 ms time window over frontocentral, and centroparietal sites than high Att-Imp subjects. Monetary gain signals elicited higher theta and gamma activities in high Att-Imp individuals and loss signals elicited higher activities to loss signals in low Att-Imp individuals. Good learners showed enhanced intrahemispheric theta synchrony between frontoparietal, and fronto-occipital sites to monetary loss compared to gain signals. In good learners, monetary loss produced an increase of gamma synchrony that enhanced in the second stage of learning. In low Att-Imp individuals, there was a reduction of theta synchrony during the second stage, as compared with the first stage of learning, between temporal, parietal and fronto-parietal brain regions. These findings may offer valuable clues to understand outcome processing, attentional impulsivity, and learning ability. We propose that the punishment-related theta and gamma waves play a leading role in learning process.

The link between preschoolers' executive function and theory of mind and the role of epistemic states

The aim of this study was to assess the specific relation between 3- to 6-year-olds' performance on a task measuring executive function (EF), the Dimensional Change Card Sort task (DCCS), and different developmental attainments in their theory of mind (ToM) by employing a battery of scaled ToM tasks that were comparable in task format and task demands. In addition, individual differences on the temperamental dimensions emotionality, activity, sociability, and shyness were assessed by parental rating. The main findings show that children's (N=195) performance on the DCCS related to their overall performance on the ToM scale but that this relation was specific to those ToM tasks that tap children's understanding of epistemic states such as knowledge access, diverse beliefs, and false beliefs regarding content and location. The relation between children's EF and overall ToM performance remained significant after controlling for age, sentence comprehension, child temperament, and parental education. Individual differences in child activity showed consistent negative relation to EF and ToM abilities. The findings point to a differential involvement of the various EF components in reasoning about different mental concepts.

Taxing executive processes does not necessarily increase impulsive decision making

A link has been established between impulsivity in real-world situations and impulsive decision making in laboratory tasks in brain-damaged patients and individuals with substance abuse. Whether or not this link exists for all individuals is less clear. We conducted an experiment to determine whether taxing central executive processes with a demanding cognitive load task results in impulsive decision making in a normal sample. Participants (n = 53) completed a delay discounting task under the presence (load condition) and absence (control condition) of a demanding generation task. Results indicated that taxing working memory is neither necessary nor sufficient to produce impulsive decision making; instead, the demanding generation task resulted in an increase in the number of inconsistent choices.

Temperament and Character Correlates of Neuropsychological Performance

We investigate the association between temperament and character dimensions, on the one hand, and computerised neuropsychological test performance, on the other hand. Temperament and character dimensions were operationalised as scores on the subscales of the Temperament and Character Inventory (TCI), a 240-item measure that is based on the psychobiological theory of personality. Neuropsychological outcomes were measured on six computerised tests of executive functioning and abstract reasoning from the University of Pennsylvania Computerised Neuropsychological Test Battery (PennCNP). The executive and abstract reasoning tasks included a test of Motor Praxis (MPRAXIS), the Penn Abstraction, Inhibition and Working Memory Task (AIM), the Letter-N-Back (LNB2), the Penn Conditional Exclusion Task (PCET), the Penn Short Logical Reasoning Task (SPVRT) and the Short Raven's Progressive Matrices (SRAVEN). Results from this exploratory study yielded significant associations between neuropsychological performance and temperament and character traits. The temperament traits of Harm Avoidance and Reward Dependence were positively correlated with reaction time on the AIM and the SPVRT. The character dimension of Self-Transcendence was significantly associated with performance accuracy on the AIM and the temperament dimension of Novelty Seeking was inversely related to performance accuracy on the LNB2. These results confirm the importance of addressing the temperament and character correlates of neuropsychological performance in both clinical and non-clinical studies.

Self-reported differences on measures of executive function and hypersexual behavior in a patient and community sample of men

Patients seeking help for hypersexual behavior often exhibit features of impulsivity, cognitive rigidity, poor judgment, deficits in emotion regulation, and excessive preoccupation with sex. Some of these characteristics are also common among patients presenting with neurological pathology associated with executive dysfunction. These observations led to the current investigation of differences between a group of hypersexual patients (n = 87) and a non-hypersexual community sample (n = 92) of men using the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A) and the Hypersexual Behavior Inventory (HBI). Significant differences between the groups emerged on eight subscales and all of the general indices of executive functioning with the most dramatic differences on BRIEF-A's Shift, Emotional Control, Initiate, and Plan/Organize subscales. Hypersexual behavior was positively correlated (r = .37, p < .01) with global indices of executive dysfunction and several subscales of the BRIEF-A. These findings provide preliminary evidence supporting the hypothesis that executive dysfunction may be implicated in hypersexual behavior.

Effects of sleep deprivation on dissociated components of executive functioning

STUDY OBJECTIVES

We studied the effects of sleep deprivation on executive functions using a task battery which included a modified Sternberg task, a probed recall task, and a phonemic verbal fluency task. These tasks were selected because they allow dissociation of some important executive processes from non-executive components of cognition.

DESIGN

Subjects were randomized to a total sleep deprivation condition or a control condition. Performance on the executive functions task battery was assessed at baseline, after 51 h of total sleep deprivation (or no sleep deprivation in the control group), and following 2 nights of recovery sleep, at fixed time of day (11:00). Performance was also measured repeatedly throughout the experiment on a control task battery, for which the effects of total sleep deprivation had been documented in previously published studies.

SETTING

Six consecutive days and nights in a controlled laboratory environment with continuous behavioral monitoring.

PARTICIPANTS

Twenty-three healthy adults (age range 22-38 y; 11 women). Twelve subjects were randomized to the sleep deprivation condition; the others were controls.

RESULTS

Performance on the control task battery was considerably degraded during sleep deprivation. Overall performance on the modified Sternberg task also showed impairment during sleep deprivation, as compared to baseline and recovery and compared to controls. However, two dissociated components of executive functioning on this task--working memory scanning efficiency and resistance to proactive interference--were maintained at levels equivalent to baseline. On the probed recall task, resistance to proactive interference was also preserved. Executive aspects of performance on the phonemic verbal fluency task showed improvement during sleep deprivation, as did overall performance on this task.

CONCLUSION

Sleep deprivation affected distinct components of cognitive processing differentially. Dissociated non-executive components of cognition in executive functions tasks were degraded by sleep deprivation, as was control task performance. However, the executive functions of working memory scanning efficiency and resistance to proactive interference were not significantly affected by sleep deprivation, nor were dissociated executive processes of phonemic verbal fluency performance. These results challenge the prevailing view that executive functions are especially vulnerable to sleep loss. Our findings also question the idea that impairment due to sleep deprivation is generic to cognitive processes subserved by attention.

Individual differences in delay discounting: relation to intelligence, working memory, and anterior prefrontal cortex

Lower delay discounting (better self-control) is linked to higher intelligence, but the basis of this relation is uncertain. To investigate the potential role of working memory (WM) processes, we assessed delay discounting, intelligence (g), WM (span tasks, 3-back task), and WM-related neural activity (using functional magnetic resonance imaging) in 103 healthy adults. Delay discounting was negatively correlated with g and WM. WM explained no variance in delay discounting beyond that explained by g, which suggests that processes through which WM relates to delay discounting are shared by g. WM-related neural activity in left anterior prefrontal cortex (Brodmann's area 10) covaried with g, r= .26, and delay discounting, r=-.40, and partially mediated the relation between g and delay discounting. Overall, the results suggest that delay discounting is associated with intelligence in part because of processes instantiated in anterior prefrontal cortex, a region known to support the integration of diverse information.

Structure and Correlates of the German Version of the Brief UPPS Impulsive Behavior Scales

The article proposes a shortened German version of the UPPS impulsive behavior scales. In Study 1, 149 high-school students completed the UPPS questionnaire, a Big-Five questionnaire, additional established self-report scales to measure conscientiousness and impulsivity, as well as tests of working memory capacity, reasoning, and clerical speed. Measurement models were applied to the full translated UPPS scales using confirmatory factor analysis. A satisfactory measurement model could be established only by removing many of the initial items. The remaining items correlated as expected with other self-report and ability measures: Substantial correlations with impulsivity and conscientiousness contrasted with zero correlations with working memory and reasoning ability. The association between impulsivity factors and perceptual speed was primarily a result of the number of solved items rather than the number of mistakes in the speed tasks. In Study 2 the reduced item set from Study 1 was administered to 246 participants to replicate the model. The fit of this model supports the construct validity of the final item set. The generally low correlations of the UPPS with cognitive variables questions interpretations of self-reported impulsivity that are overly focused on cognition. More appropriate cognitive criteria for impulsivity constructs should be established.

Cognitive-behaviour therapy and skilled motor performance in adults with chronic tic disorder

The first aim of the present study was to compare performance of people with tic disorders (TD) and controls on executive function and a range of skilled motor tests requiring complex performance, guided movements, hand co-ordination, and fine control of steadiness. The second aim was to investigate the effect of cognitive behaviour therapy (CBT) on motor performance. A total of 55 patients with TD were recruited at baseline from participants in a behavioural management programme. A comparison group of 55 patients suffering from a variety of habit disorders (HD) involving complex manual movements, were matched on age and level of education to 34 non-psychiatric controls. Participants were evaluated pre- and post-treatment and post-waitlist with a neuropsychological evaluation focusing on executive function (Wisconsin Card Sorting Test, WCST) and skilled motor performance (Purdue Pegboard, Hole Steadiness Test, and the Groove Test). Results revealed WCST scores in the normal range, while motor performance differed significantly on the Purdue Pegboard Tests in both TD and HD as compared to the control group. Cognitive-behavioural treatment selectively improved motor performance in both clinical groups compared to waitlist control, and this improvement related to clinical outcome measures.

Relationship between impulsivity, hyperactivity and working memory: a differential analysis in the rat

BACKGROUND

Impulsivity is a behavioural trait that comprises several distinct processes. It is a key feature of many psychopathologies such as mania, addictive disorders or attention deficit-hyperactivity disorders. To date, the aspects of impulsiveness involved in these pathologies have not yet been explicitly defined. In these disorders, sensation or drug seeking and cognitive deficits are closely related, but the nature of these relationships remains largely unknown. A new animal model of impulsiveness based on spontaneous inter-individual differences is proposed here to help clarify the relationship between characteristic aspects of impulsive-related pathologies.

METHODS

Rats were divided into sub-groups according to their scores in three operant tasks with varying degrees of behavioural inhibition, timing and motor vs. cognitive impulsivity demands. These tasks included a fixed consecutive number schedule (ability to complete an action to receive a reinforcer), a multiple fixed-interval/extinction schedule of reinforcement (high level of responding), and a delayed reward task (delay discounting). In addition, measurements of locomotor responses to novelty and to amphetamine in a circular corridor, and working memory in an 8-arm radial maze were obtained.

RESULTS

Substantial behavioural inter-individual differences were observed in each task, whereas few inter-task relationships were found. Impulsive rats, as defined in a task requiring inhibition of premature responses, presented a higher increase in amphetamine-induced locomotion. Reduced working memory performance was only observed in hyperactive rats in an extinction schedule.

CONCLUSION

This novel approach shows that distinct aspects of impulsiveness and hyperactivity can be expressed based on large inter-individual differences that vary from poorly to highly adapted behaviours ones in a normal population of rats. Inhibitory deficit was related to a higher response to psychostimulants a characteristic of rats predisposed to amphetamine self-administration and related to higher limbic dopaminergic activity, whereas working memory capacity was only related to hyperactivity. This approach allows for the identification of particular individuals presenting distinct behavioural characteristics of impulsive-related psychopathologies. These individuals may be of great interest in the modelling of these disorders and the exploration of their neurobiological bases.