Low Impulsive Subjects Research Articles

To Regulate or Not to Regulate: Emotion Regulation in Participants With Low and High Impulsivity.

Successful emotion regulation plays a key role in psychological health and well-being. This study examines (1) whether cognitive control and corresponding neural connectivity are associated with emotion regulation and (2) to what extent external instructions can improve emotion regulation in individuals with low vs. high cognitive control capacity. For this, emotion regulation capabilities and the impact of emotion regulation on a subsequent emotional Stroop task was tested in participants with low (N = 25) vs. high impulsivity (N = 32). The classification according to impulsivity is based upon the stable correlation between high impulsivity and reduced cognitive control capacity. A negative emotion inducing movie scene was presented with the instruction to either suppress or allow all emotions that arose. This was followed by an emotional Stroop task. Electromyography (EMG) over the corrugator supercilii was used to assess the effects of emotion regulation. Neurophysiological mechanisms were measured using functional near-infrared spectroscopy over frontal brain areas. While EMG activation was low in the low-impulsive group independent of instruction, high-impulsive participants showed increased EMG activity when they were not explicitly instructed to suppress arising emotions. Given the same extent of functional connectivity within frontal lobe networks, the low-impulsive participants controlled their emotions better (less EMG activation) than the high-impulsive participants. In the Stroop task, the low-impulsive subjects performed significantly better. The emotion regulation condition had no significant effect on the results. We conclude that the cognitive control network is closely associated with emotion regulation capabilities. Individuals with high cognitive control show implicit capabilities for emotion regulation. Individuals with low cognitive control require external instructions (= explicit emotion regulation) to achieve similarly low expressions of emotionality. Implications for clinical applications aiming to improve emotion regulation are discussed.

Fast or safe? The role of impulsiveness in laparoscopic simulator performance

BackgroundLittle is known about the relation between impulsiveness and surgical performance even though research in similar high-risk/high-skills shows evidence of more hazardous behavior by impulsive professionals. We investigated the impact of impulsiveness on laparoscopic simulator performance. MethodsEighty-three subjects participated in a four-session laparoscopic training course. Based on the Eysenck Personality test, we created equal sized high- and low impulsiveness groups and compared task duration and errors on tasks for two laparoscopic simulators. ResultsThe low impulsiveness group outperformed the high impulsiveness group on damage on the LapSim virtual reality trainer (U = 459, p < .049), and showed a trend towards better error performance on the FLS videotrainer. We found no differences on task duration. ConclusionsIn surgical simulation training, high impulsiveness is associated with creating more damage, but not with faster performance. Time needed to correct errors may have obscured faster performance in the high impulsiveness group. Summary for the table of contentsSubjects were divided into high- and low impulsiveness groups based on the Eysenck Impulsiveness Inventory test. Performance (time and errors) were compared between groups for tasks on the LapSim virtual reality trainer and FLS videotrainer. Low impulsive subjects outperformed high impulsive subjects on errors.

Validating a behavioral economic approach to assess food demand: Effects of body mass index, dietary restraint, and impulsivity

Behavioral economic theory is a useful framework for analyzing factors influencing choice, but the majority of human behavioral economic research has focused on drug choice. The behavioral economic choice paradigm may also be valuable for understanding food-maintained behavior. Our primary objective was two-fold: (1) Validate a human laboratory model of food-appetitive behavior, and (2) Assess the contribution of individual level factors that may differentially impact food choice behavior. Two studies were conducted. In Study 1, female subjects (N=17) participated in two consecutive food choice experimental sessions, whereas in Study 2, female subjects (N=21) participated in one concurrent food choice experimental session. During consecutive choice sessions (Study 1), demand for the more palatable food (i.e., high-sugar/high-fat) was more inelastic than the less palatable (i.e., low-sugar/low-fat) option. During concurrent choice sessions, demand for the more palatable food (i.e., high-sugar/high-fat) was more inelastic for restrained vs. unrestrained eaters, and for those who were overweight vs. normal weight. Demand for both palatable and less palatable choices was more elastic for high-impulsive vs. low-impulsive subjects. These findings suggest that the behavioral economic framework can be used successfully to develop a human laboratory model of food-appetitive behavior.

Dimensions of Impulsivity Are Associated with Poor Spatial Working Memory Performance in Monkeys

Impulsive behavior and novelty seeking are dimensions of temperament that are behavioral determinants of risk for attention deficit/hyperactivity disorder and its neurocognitive endophenotypes, and variation in the dopamine D4 receptor gene (DRD4) explains at least a portion of the variance in the traits. To further characterize the dimensional phenotype associated with impulsiveness, adolescent male monkeys were evaluated using ecologically valid tests of impulsive approach and aggression in response to social or nonsocial stimuli; subsequently, a delayed response task was implemented to assess spatial working memory performance. Subjects were selected into this study based on their response to the social challenge task or by DRD4 genotype, resulting in three groups: low-impulsivity/common DRD4 allele, high-impulsivity/common DRD4 allele, or rare DRD4 allele. All animals acquired the delayed response task and could perform at near ceiling levels when a approximately 0 s delay version was imposed, but as delays were lengthened, high-impulsive animals, regardless of DRD4 genotype, made fewer correct responses than did low-impulsive subjects; an inverse relationship existed for working memory and impulsivity. Notably, impulsive behavior evoked by social and nonsocial stimuli explained overlapping and independent portions of the variance in working memory performance. CSF levels of monoamine metabolites did not significantly differentiate the high- and low-impulsive animals, although monkeys carrying the DRD4 rare allele tended to exhibit higher monoamine turnover. These data indicate that dimensions of impulsivity may impact on working memory performance in qualitatively similar ways but through different mechanisms.

Attention switching after dietary brain 5-HT challenge in high impulsive subjects

High levels of impulsivity have adverse effects on performance in cognitive tasks, particularLy in those tasks that require high attention investment. Furthermore, both animal and human research has indicated that reduced brain serotonin (5-HT) function is associated with increases in impulsive behaviour or decreased inhibition ability, but the effects of 5-HT challenge have not yet been investigated in subjects vulnerable to impulsivity. The present study aimed to investigate whether subjects with high trait impulsivity perform worse than low impulsive subjects in a task switching paradigm in which they have to rapidly shift their attention between two response rules, and to investigate the influence of a 5-HT enhancing diet. Healthy subjects with high ( n = 19) and low (n = 18) trait impulsivity scores participated in a double-blind placebo-controlled study. All subjects performed the attention switch task in the morning following breakfast containing either tryptophan-rich alpha-lactalbumin (4.8 g/100 g TRP) or placebo protein (1.4 g/100 g TRP). Whereas there were no baseline differences between high and low impulsive subjects in task switching abilities, high impulsive subjects made significantly more switch errors and responded slower after dietary 5-HT stimulation, whereas no dietary effects were found on task switching performance in low-impulsive subjects. The deterioration in task switching performance induced by the 5-HT enhancing diet in high impulsive subjects was suggested to be established by general arousal/attention-reducing effects of 5-HT, which might have a larger impact in high impulsive subjects due to either different brain circuitry involved in task switching in this group or lower baseline arousal levels.

Impulsive Personality Predicts Dopamine-Dependent Changes in Frontostriatal Activity during Component Processes of Working Memory

Dopaminergic drugs affect a variety of cognitive processes, but the direction and extent of effects vary across individuals and tasks. Paradoxical effects are observed, by which the same drug causes cognitive enhancing as well as adverse effects. Here, we demonstrate that individual differences in impulsive personality account for the contrasting effects of dopaminergic drugs on working memory and associated frontostriatal activity. We observed that the dopamine D2 receptor agonist bromocriptine improved the flexible updating (switching) of relevant information in working memory in high-impulsive subjects, but not in low-impulsive subjects. These behavioral effects in high-impulsive subjects accompanied dissociable effects on frontostriatal activity. Bromocriptine modulated the striatum during switching but not during distraction from relevant information in working memory. Conversely, the lateral frontal cortex was modulated by bromocriptine during distraction but not during switching. The present results provide a key link between dopamine D2 receptor function, impulsivity, and frontostriatal activity during component processes of working memory.

Alcohol expectancies, conduct disorder and early‐onset alcoholism: negative alcohol expectancies are associated with less drinking in non‐impulsive versus impulsive subjects

Research suggests that positive alcohol expectancies promote excessive alcohol use while negative alcohol expectancies discourage excessive alcohol use. Evidence suggests that disinhibitory characteristics, such as conduct disorder and impulsivity, are associated with a general neglect of long-term negative outcomes. This study assessed whether negative expectancies would be associated more strongly with lower levels of alcohol use for low- compared with high-impulsive individuals. Positive and negative alcohol expectancies, alcohol use and impulsivity were assessed in a sample of 99 young adults with alcohol dependence (AD) and conduct disorder (CD), 77 with AD and no CD and 124 controls. AD/CD subjects had higher proximal (same day) and distal (next day) negative alcohol expectancies, even though they drank more alcohol, compared with AD-alone and control subjects. Distal negative expectancies were associated more strongly with lower levels of drinking for low-impulsive compared with high-impulsive subjects. Proximal negative expectancies were associated more strongly with higher alcohol consumption for high- versus low-impulsive subjects. Impulsivity and conduct disorder may be important factors in determining how much distal negative alcohol expectancies may discourage excessive alcohol consumption.

Behavioural and psychometric measures of impulsivity in a personality disordered population

The relationship between psychometric and behavioural measures of impulsivity has not been extensively examined in violent personality disordered samples. We examined the relationship between psychometric and behavioural measures of impulsivity in 40 male, medication free, personality-disordered offenders with a history of violent offences. Subjects were categorized into high and low impulsivity groups based on psychometric measures and on the nature of their institutional violence. Group differences in performance on behavioural impulsivity measures were examined. High (trait)-impulsive subjects had significantly higher scores on all psychometric measures of impulsivity, poorer behavioural inhibition and an inability to delay gratification than low impulsive subjects. Within the institution, subjects who were categorized as predominately instrumentally violent had lower trait impulsivity, fewer incidents, and a greater ability to inhibit responses on behavioural tasks than those who were reactively violent. In the overall sample behavioural measures did not correlate well with psychometric measures of impulsivity and these measures appear to assess different constructs.

Reward sensitivity in impulsivity.

Impulsive individuals choose immediate small over delayed larger rewards, suggesting reward hypersensitivity. Single-unit studies have shown increased ventral tegmental activity to rewards and reward predictors and decreased activity when predicted rewards are withheld. The orbitofrontal ventral tegmental cortical target also responds to reward and expectation in single-unit and neuroimaging studies. The anterior P2a event-related potential component is a proposed index of reward-related orbitofrontal activity. In this reward prediction study in high and low impulsive subjects, the P2a localized to orbitofrontal cortex and was largest to non-predicted rewards and smallest in the absence of predicted rewards in subjects higher on self-reported impulsiveness, consistent with a P2a index of orbitofrontal reward processing and with reward hypersensitivity in impulsivity.

Impulsiveness and risk-taking behavior: comparison of high-school and college students using the Barratt Impulsiveness Scale

The present study was undertaken in an attempt to determine the relationship of impulsiveness to risk-taking behaviors such as aggression, drug use, drunk driving and not wearing seatbelts among highschool and college students. The results of the study clearly demonstrate that high impulsives are involved in risk-taking behavior at a higher rate than low impulsive subjects. These findings suggest that high impulsive adolescents and young adults are at considerable risk of personal injury and present a potential source of injury to others. It is suggested that self-report questionnaires of impulsiveness might prove useful in the early identification of these high risk individuals. Once identified these individuals could be targeted for intensive educational interventions specifically designed to deal with their inability to delay gratification and general lack of impulse control.

Personality, reaction time, and event-related potentials.

Reaction time (RT), movement time (MT), and the amplitude and latency of the P300 event-related potential were recorded from 30 Ss during the performance of 6 simple cognitive tasks. Extraversion was negatively associated with MT, a result that endorses the view that extraversion is determined, in part, by individual differences in motor mechanisms. Higher neuroticism scores were associated with faster P300 latency, a measure that is regarded as an index of stimulus evaluation time that is independent of response production. Paradoxically, higher neuroticism scores were associated with slower RT, a measure that is also regarded as an index of speed of information processing. Higher psychoticism scores were associated with smaller P300 amplitude, an effect that may be indicative of less attentional effort invested in the tasks. The analyses of individual differences in the response to sensory stimulation and in the expression of motor responses are important sources of evidence for several proposals that have been put forward in the explanation of personality differences, notably extraversion, impulsiveness, and anxiety (Barratt, 1972; Brebner & Cooper, 1974; H. J. Eysenck, 1957; Newman, 1987; Stelmack, 1985). The present article aims to articulate differences in the processing of stimuli and production of responses that are relevant to the biological bases of those personality dimensions by exploiting relatively recent refinements in eventrelated potential (ERP) and reaction time (RT) measures that are recorded during the performance of simple cognitive tasks. This article addresses several questions that have emerged in the study of individual differences in extraversion and impulsiveness. At this time, there is a good deal of evidence from research using both behavioral and psychophysiological measures that demonstrates the greater sensory reaction to simple physical stimulation for introverts than extraverts (Stelmack, 1990). However, it is unclear whether these effects reflect differences at early stages of stimulus input, central stimulus analysis, or both. There is also a literature spanning 30 years that affirms differences between extraverts and introverts and between high- and low-impulsive subjects in their performance on various tasks that assess speed of responding and motor control (Barratt & Patton, 1983; Stelmack, 1985). Again, it is not clear whether these effects involve differences in central processing, motor response, or both. This issue is complicated because impulsiveness can be described as a complex construct composed of facets of extraversion, neuroticism, and psychoticism (H. J.

Impulsivity and the multi-impulsive personality disorder

The purpose of this study was to test the hypothesis that impulsiveness is positively related to the total number of categories of distinct impulse control incidents. That is, high impulsive individuals are more likely to be involved in more separate types of impulsive acts than low impulsive subjects. This is an extension and replication of research done by Kennedy and Grubin [(1990) British Journal of Addiction, 85, 639–643] on the multi-impulsive personality disorder [Lacey & Evans (1986) British Journal of Addiction, 81, 641–649]. The current study extends past research by: (1) studying inmates from a general prison population; (2) controlling for IQ and educational achievement; (3) the inclusion of impulsive fire-setting as a disorder; and (4) using impulsiveness subtraits as well as a global measure of general impulsiveness. Our results indicate that an impulsiveness subtrait, motor impulsiveness, was significantly related to the number of different types of impulse control incidents an individual displays. Global impulsiveness was not related to these incidents. The number of impulse control disorders an inmate displayed was not related to age, duration of present sentence (years), educational achievement or intellect. Categories of impulsive incidents used in this study were independent except for other drug abuse and sedative dependence. These results are consistent with Kennedy and Grubin's (1990) results and support Lacey and Evans' (1986) proposed multi-impulsive personality disorder.

Caffeine differentially affects kinesthetic aftereffect in high and low impulsives

The effects of caffeine on kinesthetic aftereffect (KAE) were examined. Following a between-subjects design, high and low impulsive male postgraduate students were administered placebo and four doses of caffeine (1, 2, 3 and 4 mg/kg body weight) in a laboratory situation. A double blind procedure was adopted for drug administration. The study supports the following conclusions: (1) caffeine reduces KAE in high impulsive subjects; (2) the larger dose of caffeine (4 mg/kg) enhances KAE in low impulsive subjects; (3) caffeine produces profound effects on the performance of high impulsives; (4) caffeine leads to different dose-response trends in the two groups.

Relationships between impulsivity and eating behaviour under varying conditions of stress and food deprivation

Observations from research on Bulimia nervosa characterized by binge eating with a preference for carbohydrates, high impulsivity and lack of self-control have led to the present investigation. Since both carbohydrate craving and impulsivity are linked to changes in serotonin brain levels, we tested the following hypotheses: (a) whether bulimic subjects would consume more food, in particular more carbohydrate-rich, sweet food than the other subjects, especially when they are subjected to a frustrating stressful task or preceding food deprivation and (b) whether subjects with high levels of impulsivity would consume more food, above all more sweet food, than low scoring subjects, especially under stress or after fasting. Three factor analyses (level of impulsivity, starvation, stress) revealed the following results: high impulsive fasting Bulimics exhibited a greater intake of food in general, and sweet food in particular, than the other three groups of Bulimics. Furthermore, this interaction was reversed in controls: non-fasting, high impulsive as well as fasting, low impulsive subjects consumed a greater percentage of sweets than the other two groups.

The biological basis of impulsiveness: the significance of timing and rhythm disorders

High-impulsive subjects often do say things on the spur of the moment and/or make up their minds quickly. The description of impulsivity as a personality trait involves a number of basic research questions including: 1. 1. From a psychometric viewpoint, how inclusive or broad is impulsivity as a personality trait? 2. 2. How does impulsivity relate to other personality traits? 3. 3. Is there a pattern of biological correlates of impulsivity that is distinct from other personality traits? 4. 4. What is the relationship between cognitive and behavioral impulsivity? This paper addresses those four questions. Psychometric analysis of issues in impulsivity indicates the need for a distinction between broad and narrow impulsivity traits and further redefinition of the latter in terms of cognitive and motor components. This research has also shown that impulsiveness has an orthogonal relationship with measures of anxiety. In perceptual-motor tasks, high-impulsive subjects perform less efficiently and with greater variability on a wide range of these tasks, and in particular when the task involves responding to two or more sequential stimuli. High-impulsive subjects underproduce time intervals in time-judgment tasks; this and other findings suggest that high-impulsive subjects have a faster cognitive tempo than low-impulsive subjects. The interaction of impulsivity and anxiety in the performance of perceptual-motor tasks is also reflected in psychophysiological measures; differences in impulsivity are more evident with electrocortical measures and differences in anxiety are reflected in ANS measures while performing the tasks.