Individual Differences In Trait Impulsivity Research Articles

Trait Impulsivity Associated With Altered Resting-State Functional Connectivity Within the Somatomotor Network.

Knowledge of brain mechanisms underlying self-regulation can provide valuable insights into how people regulate their thoughts, behaviors, and emotional states, and what happens when such regulation fails. Self-regulation is supported by coordinated interactions of brain systems. Hence, behavioral dysregulation, and its expression as impulsivity, can be usefully characterized using functional connectivity methodologies applied to resting brain networks. The current study tested whether individual differences in trait impulsivity are reflected in the functional architecture within and between resting-state brain networks. Thirty healthy individuals completed a self-report measure of trait impulsivity and underwent resting-state functional magnetic resonance imaging. Using Probabilistic Independent Components Analysis in FSL MELODIC, we identified across participants 10 networks of regions (resting-state networks) with temporally correlated time courses. We then explored how individual expression of these spatial networks covaried with trait impulsivity. Across participants, we observed that greater self-reported impulsivity was associated with decreased connectivity of the right lateral occipital cortex (peak mm 46/-70/16, FWE 1-p = 0.981) with the somatomotor network. No supratheshold differences were observed in between-network connectivity. Our findings implicate the somatomotor network, and its interaction with sensory cortices, in the control of (self-reported) impulsivity. The observed “decoupling” may compromise effective integration of early perceptual information (from visual and somatosensory cortices) with behavioral control programs, potentially resulting in negative consequences.

Subthalamic Nucleus Activation Occurs Early during Stopping and Is Associated with Trait Impulsivity.

The subthalamic nucleus (STN) is thought to be a central regulator of behavioral inhibition, which is thought to be a major determinant of impulsivity. Thus, it would be reasonable to hypothesize that STN function is related to impulsivity. However, it has been difficult to test this hypothesis because of the challenges in noninvasively and accurately measuring this structure's signal in humans. We utilized a novel approach for STN signal localization that entails identifying this structure directly on fMRI images for each individual participant in native space. Using this approach, we measured STN responses during the stop signal task in a sample of healthy adult participants. We confirmed that the STN exhibited selective activation during "Stop" trials. Furthermore, the magnitude of STN activation during successful Stop trials inversely correlated with individual differences in trait impulsivity as measured by a personality inventory. Time course analysis revealed that early STN activation differentiated successful from unsuccessful Stop trials, and individual differences in the magnitude of STN activation inversely correlated with stop signal RT, an estimate of time required to stop. These results are consistent with the STN playing a central role in inhibition and related behavioral proclivities, with implications for both normal range function and clinical syndromes of inhibitory dyscontrol. Moreover, the methods utilized in this study for measuring STN fMRI signal in humans may be gainfully applied in future studies to further our understanding of the role of the STN in regulating behavior and neuropsychiatric conditions.

Catecholaminergic modulation of the avoidance of cognitive control.

The catecholamines have long been associated with cognitive control and value-based decision-making. More recently, we proposed that the catecholamines might modulate value-based decision-making about whether or not to engage in cognitive control. We test this hypothesis by assessing effects of a catecholamine challenge in a large sample of young, healthy adults (n = 100) on the avoidance of a cognitively demanding control process: task switching. Prolonging catecholamine transmission by blocking reuptake with methylphenidate altered the avoidance, but not the execution of cognitive control. Crucially, these effects could be isolated by taking into account individual differences in trait impulsivity, so that participants with higher trait impulsivity became more avoidant of cognitive control, despite faster task performance. One implication of these findings is that performance-enhancing effects of methylphenidate may be accompanied by an undermining effect on the willingness to exert cognitive control. Taken together, these findings integrate hitherto segregated literatures on catecholamines' roles in value-based learning/choice and cognitive control. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The moderating effect of impulsivity on negative affect and body checking

This study examined the moderating effects of different aspects of trait impulsivity on trajectories of negative affect prior to and following body checking in the natural environment in women with anorexia nervosa (AN). Body checking is a compulsive behavior that may maintain the cycle of eating disordered behavior through negative reinforcement. Previous studies regarding the relationship of negative affect to body checking have been inconsistent, making it unclear how negative affect functions as an antecedent to this behavior in the natural environment. We hypothesized that individual differences in trait impulsivity may influence body checking in response to negative affect. Negative urgency (NU) (the tendency to act rashly under distress) and (lack of) perseverance (the tendency to give up on goal directed behavior) may be unique facets of impulsivity that play a role in body checking. Women with AN (n = 82) completed a self-report measure of impulsivity and used ecological momentary assessment (EMA) to record negative affect and body checking for two weeks. Results indicated that women with low (lack of) perseverance experienced a greater increase in negative affect than those with high (lack of) perseverance prior to and following body checking. Overall, results indicate that individual differences in trait impulsivity moderated the relationship of negative affect to body checking in women with AN.

Electrophysiological Activity Prior to Self-initiated Movements is Related to Impulsive Personality Traits

Electrophysiological and neuroimaging studies suggest that our actions are initiated by unconscious mental processes long before awareness of intention to act. The time window between the awareness of the intention to move and the movement onset, which normally permits to exert a conscious “veto” on the impending action, is modulated by individual differences in trait impulsivity. In particular, trait impulsive people show a delayed awareness of the intention to act, probably exceeding the “point of no return”, after which the action can no longer be inhibited. In order to investigate if individual differences in the “veto” interval might be explained by differences in the readiness potential (RP) dynamics, nineteen healthy participants underwent an impulsivity trait assessment using the Barratt Impulsiveness Scale (BIS-11) and performed a task based on Libet’s clock paradigm, during EEG recordings of pre-movement neural activity. We observed a positive relationship between impulsive personality trait and motor system excitability during the preparation of self-initiated movements. In particular, the RP showed an earlier negative rising phase and a greater amplitude, with the increasing of BIS-11 scores. Based on present results, we conclude hypothesizing that trait impulsivity might be characterized by less effective preparatory inhibition mechanisms, which have a fundamental role in the control of behavior.

The relationship between dimensions of impulsivity and alcohol consumption in heavy drinkers

Introduction Impulsivity has been studied as underlying mechanism among addictive disorders such as alcohol use disorder. Several authors have suggested that impulsivity is not a unitary construct and consist of several subconstructs such as response inhibition, risk taking. Objectives This study conceptualized impulsivity as a multidimensional construct and those subconstucts of impulsivity can predict alcohol use differentially. Aims Our aim was to identify the specific component of impulsivity that explained the greatest variance in heavy and problem drinking among a sample of alcohol use disorder. Methods Participants with alcohol use disorder ( n =170) completed a behavioral test battery comprising response inhibition tasks (Stop signal task), the Balloon Analogue Risk Task (BART) as measures of subconstruct of impulsivity. Participants also completed the UPPSP as a measure of general impulsivity. Results In a multiple regression model, impulsivity measured by UPPSP and risk-taking was identified as the measures that predicted alcohol use and problems. Conclusions Results suggest that among patients with alcohol use disorder, a behavioral measure of risk-taking predicts alcohol consumption and alcohol problems, even when individual differences in trait impulsivity are statistically controlled. However, behavioral measures of response inhibition do not predict unique variance in alcohol use in patients with alcohol use disorders.

Future Directions in Emotion Dysregulation and Youth Psychopathology

This article reviews central nervous system substrates and autonomic correlates of emotion dysregulation and offers several suggestions for future research. Studies conducted in the last two decades indicate that effective emotion regulation requires efficient top-down, cortically mediated regulation of bottom-up, subcortically mediated individual differences in trait impulsivity and trait anxiety. Without making critical distinctions between highly heritable individual differences in trait impulsivity and trait anxiety, versus less heritable and more socialized deficiencies in emotion regulation, progress in understanding the development of psychopathology among children and adolescents will be hampered. Future research can also be improved by measuring emotion dysregulation across multiple level of analysis, specifying physiological mechanisms through which operant reinforcement shapes emotional lability, improving the internal and external validity of psychophysiological measures, integrating emotion dysregulation into factor analytic and behavioral genetic models of psychopathology, identifying molecular genetic risk for emotion dysregulation, and expanding neuroimaging research on emotion dysregulation among children and adolescents.

Acute alcohol effects on impulsivity: associations with drinking and driving behavior

Although drink drivers exhibit higher levels of trait impulsivity, no studies have tested the hypothesis that drink drivers experience increased impulsivity while intoxicated. We tested this hypothesis for two impulsivity constructs: delay discounting and behavioral inhibition. A within-subjects study comparing performance of drink drivers and non-drink drivers on behavioral measures of impulsivity in alcohol and no-beverage sessions. A laboratory setting at the University of Missouri. Twenty-nine young adults who were at least moderate drinkers were recruited from the local community and the University of Missouri. Impulsivity was assessed using the Two Choice Impulsivity Paradigm (TCIP) and the Stop-Signal Task. Participants also completed self-report measures of binge drinking and trait impulsivity. In the no-beverage session, TCIP impulsive choices did not differ between drinking and driving groups (P = 0.93). In the alcohol session, drink drivers made more TCIP impulsive choices on both the ascending (P < 0.01) and descending limb (P < 0.01) of the blood alcohol concentration curve than their peers who did not drink and drive. Drinking and driving groups did not differ on the Stop-Signal Task. Supplementary analyses indicated that effects for the TCIP were not explained by individual differences in trait impulsivity. Individuals who report having three or more drinks before driving show greater impulsivity when under the influence of alcohol than those who do not report heavy drinking before driving.

Dopamine-Dependent Architecture of Cortico-Subcortical Network Connectivity

Maladaptive dopaminergic mediation of reward processing in humans is thought to underlie multiple neuropsychiatric disorders, including addiction, Parkinson's disease, and schizophrenia. Mechanisms responsible for the development of such disorders may depend on individual differences in neural signaling within large-scale cortico-subcortical circuitry. Using a combination of functional neuroimaging and pharmacological challenges in healthy volunteers, we identified opposing dopamine agonistic and antagonistic neuromodulatory effects on distributed functional interactions between specific subcortical regions and corresponding neocortical "resting-state" networks, known to be involved in distinct aspects of cognition and reward processing. We found that, relative to a placebo, levodopa and haloperidol challenges, respectively, increased or decreased the functional connectivity between (1) the midbrain and a "default mode" network, (2) the right caudate and a right-lateralized frontoparietal network, and (3) the ventral striatum and a fronto-insular network. Further, we found drug-specific associations between brain circuitry reactivity to dopamine modulation and individual differences in trait impulsivity, revealing dissociable drug-personality interaction effects across distinct dopamine-dependent cortico-subcortical networks. Our findings identify possible systems underlying pathogenesis and treatment efficacy in disorders of dopamine deficiency.

Mesolimbic recruitment by nondrug rewards in detoxified alcoholics: Effort anticipation, reward anticipation, and reward delivery

Aberrant sensitivity of incentive neurocircuitry to nondrug rewards has been suggested as either a risk factor for or consequence of drug addiction. Using functional magnetic resonance imaging, we tested whether alcohol-dependent patients (ADP: n = 29) showed altered recruitment of ventral striatal (VS) incentive neurocircuitry compared to controls (n = 23) by: (1) cues to respond for monetary rewards, (2) post-response anticipation of rewards, or (3) delivery of rewards. Using an instrumental task with two-stage presentation of reward-predictive information, subjects saw cues signaling opportunities to win $0, $1, or $10 for responding to a target. Following this response, subjects were notified whether their success would be indicated by a lexical notification (“Hit?”) or by delivery of a monetary reward (“Win?”). After a variable interval, subjects then viewed the trial outcome. We found no significant group differences in voxelwise activation by task contrasts, or in signal change extracted from VS. Both ADP and controls showed significant VS and other limbic recruitment by pre-response reward anticipation. In addition, controls also showed VS recruitment by post-response reward-anticipation, and ADP had appreciable subthreshold VS activation. Both groups also showed similar mesolimbic responses to reward deliveries. Across all subjects, a questionnaire measure of “hot” impulsivity correlated with VS recruitment by post-response anticipation of low rewards and with VS recruitment by delivery of low rewards. These findings indicate that incentive-motivational processing of nondrug rewards is substantially maintained in recovering alcoholics, and that reward-elicited VS recruitment correlates more with individual differences in trait impulsivity irrespective of addiction.

The neural correlates of intertemporal decision‐making: Contributions of subjective value, stimulus type, and trait impulsivity

Making choices between payoffs available at different points in time reliably engages a decision-making brain circuit that includes medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC), and ventral striatum (VS). Previous neuroimaging studies produced differing accounts of the functions of these regions, including that these regions: (1) are sensitive to the value of rewards discounted by a function of delay ('subjective value'); (2) are differentially sensitive to the availability of an immediate reward; and (3) are implicated in impulsive decision-making. In this event-related fMRI study of 20 volunteers, these hypotheses were investigated simultaneously using a delay discounting task in which magnitude of rewards and stimulus type, i.e., the presence or absence of an immediate option, were independently varied, and in which participants' trait impulsivity was assessed with the Barratt Impulsiveness Scale. Results showed that mPFC, PCC, and VS are sensitive to the subjective value of rewards, whereas mPFC and PCC, but not VS, are sensitive to the presence of an immediate reward in the choice option. Moderation by individual differences in trait impulsivity was specific to the mPFC. Conjunction analysis showed significant overlap in mPFC and PCC for the main effects of subjective value and stimulus type, indicating these regions may serve multiple distinct roles during intertemporal decision-making. These findings significantly advance our understanding of the specificity and overlap of functions subserved by different regions involved in intertemporal decision-making, and help to reconcile conflicting accounts in the literature.

Risk-taking but not response inhibition or delay discounting predict alcohol consumption in social drinkers

Impulsivity and risk-taking are multi-dimensional constructs that have been implicated in heavy drinking and alcohol problems. Our aim was to identify the specific component of impulsivity or risk-taking that explained the greatest variance in heavy and problem drinking among a sample of young adults recruited from a university population. Participants ( N = 75) completed a test battery comprising two commonly used response inhibition tasks (a Go/No-Go task and a Stop signal task), a delay discounting procedure, and the Balloon Analogue Risk Task (BART) as a measure of risk-taking. Participants also completed the Barratt Impulsivity Scales (BIS) as a measure of trait impulsivity. In a hierarchical multiple regression model, risk-taking was identified as the only behavioural measure that predicted alcohol use and problems. In a secondary analysis, we demonstrated that risk-taking predicted unique variance in alcohol use and problems over and above that explained by trait impulsivity. Results suggest that among young adults, a behavioural measure of risk-taking predicts variance in alcohol consumption and alcohol problems, even when individual differences in trait impulsivity are statistically controlled. However, behavioural measures of response inhibition and delay discounting do not predict unique variance in alcohol use in young adult social drinkers.

Specificity of P3 event-related potential reactivity to alcohol cues in individuals low in alcohol sensitivity.

Recent research using event-related potentials (ERPs) has shown that individuals low in alcohol sensitivity show increased P3 reactivity to alcohol cues (Bartholow, Henry, & Lust, 2007). The current research sought to test the specificity of this effect by including other arousing cues in addition to alcohol, and by controlling for individual differences in trait impulsivity. Forty-seven participants varying in self-reported alcohol sensitivity completed a visual oddball task including neutral, arousing (erotic and adventure-related), and beverage-related images while ERPs were recorded. Low-sensitivity participants showed increased P3 reactivity to alcohol cues relative to their high-sensitivity peers. However, P3 amplitude elicited by all other targets did not differ as a function of alcohol sensitivity levels. Differences in impulsivity and recent alcohol consumption did not account for sensitivity group differences in alcohol cue reactivity. These results point to the specific motivational salience of alcohol cues to individuals at risk for alcohol problems because of low alcohol sensitivity and suggest that P3 reactivity to alcohol cues could be a new endophenotype for alcohol use disorder risk.

Dopamine Release in Dissociable Striatal Subregions Predicts the Different Effects of Oral Methylphenidate on Reversal Learning and Spatial Working Memory

Previous data suggest that methylphenidate can have variable effects on different cognitive tasks both within and between individuals. This is thought to be underpinned by inverted U-shaped relationships between cognitive performance and dopaminergic activity in relatively separate fronto-striatal circuits and reflected by individual differences in trait impulsivity. Direct evidence for this is currently lacking. In this study, we demonstrate for the first time that therapeutic doses of oral methylphenidate administered to young healthy subjects result in different sized changes in D(2)/D(3) receptor availability in different regions of the human striatum and that the change in receptor availability within an individual subregion predicts cognitive performance on a particular task. Methylphenidate produced significantly different effects on reversal learning and spatial working memory tasks within individuals. Performance on the reversal learning task was predicted by the drug-induced change in D(2)/D(3) receptor availability in postcommissural caudate, measured using [(11)C]-raclopride radioligand PET imaging, whereas performance on the spatial working memory task was predicted by changes in receptor availability in the ventral striatum. Reversal learning performance was also predicted by subjects' trait impulsivity, such that the most impulsive individuals benefited more from methylphenidate, consistent with this drug's beneficial effects on cognition in attention deficit hyperactivity disorder.

Distinguishing Between Learning and Motivation in Behavioral Tests of the Reinforcement Sensitivity Theory of Personality

According to Gray's (1973) Reinforcement Sensitivity Theory (RST), a Behavioral Inhibition System (BIS) and a Behavioral Activation System (BAS) mediate effects of goal conflict and reward on behavior. BIS functioning has been linked with individual differences in trait anxiety and BAS functioning with individual differences in trait impulsivity. In this article, it is argued that behavioral outputs of the BIS and BAS can be distinguished in terms of learning and motivation processes and that these can be operationalized using the Signal Detection Theory measures of response-sensitivity and response-bias. In Experiment 1, two measures of BIS-reactivity predicted increased response-sensitivity under goal conflict, whereas one measure of BAS-reactivity predicted increased response-sensitivity under reward. In Experiment 2, two measures of BIS-reactivity predicted response-bias under goal conflict, whereas a measure of BAS-reactivity predicted motivation response-bias under reward. In both experiments, impulsivity measures did not predict criteria for BAS-reactivity as traditionally predicted by RST.