Browsing by Subject "Impulsivity"

Now showing 1 - 6 of 6
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    Delay and probability discounting: a longitudinal study of neural, cognitive, and emotional processes contributing to adolescent development.
    (2010-06) Olson, Elizabeth Ayer
    Adolescence is a time of rapid change in neurobehavioral characteristics, including emotional functioning, cognitive performance, and brain structure and function. The development of decision-making was examined in a group of adolescents (age 9-23) followed longitudinally over a two-year period. Delay and probability discounting tasks were used to assess decision-making. Change in discounting was examined in relation to baseline intelligence, working memory performance, personality factors, and internalizing and externalizing behaviors. In addition, contributions of brain structural features to the development of discounting behavior were analyzed. These included cortical thickness, white matter volume, subcortical volume, and diffusion tensor imaging (DTI) measures including fractional anisotropy and mean diffusivity. Delay discounting, but not probability discounting, showed significant maturation within individuals. Greater than expected maturation in delay discounting was seen in individuals with lower internalizing and externalizing psychopathology and higher positive emotionality. Brain structural factors predisposing toward greater than expected maturation included lower right frontal cortical thickness, larger cinguate and cuneate white matter volumes, larger hippocampal volumes, thicker parahippocampal gyrus cortical thickness, lower fractional anisotropy in the right temporal-parietal-occipital junction, and lower fractional anisotropy in the right amygdala/ pallidum/ hippocampus. Behavioral factors predisposing toward greater than expected change in probability discounting included female sex (for younger participants) and working memory performance (for males). Brain structural factors predisposing toward greater than expected change included cingulate white matter volume and higher mean diffusivity in the left parieto-occipital area. Findings are discussed in terms of implications for development of decision-making processes during adolescence.
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    Delay discounting as a measure of impulsivity.
    (2012-08) Gu, Lidan
    Delay discounting as a behavioral measure of impulsivity has been widely used in neuroeconomy, psychopathology, clinical neuroscience, and drug addiction studies. Previous psychological studies have suggested that: 1) a hyperbolic function best describes the decision behaviors of humans and other animals; 2) drug users tend to have higher delay discounting rates than controls; and 3) the associations between delay discounting rate and personality measures of delay discounting are inconsistent across studies. However, neuroimaging studies have often observed two neural systems involved in delay discounting, and a number of neural models have been proposed to describe delay discounting. The studies reported in this dissertation investigated delay discounting as a behavioral measure of impulsivity when considering the neural models. In Chapter 1, delay discounting and its designs, task procedures, analysis models, reliability, and validity are reviewed. Based on previous studies, the delay discounting rate is influenced by the design of delay discounting tasks such as reward magnitude; the delay discounting rate reliably differentiates drug users from controls; and its reliability is high within a normal population but is relatively lower in clinical populations. In Chapter 2, the current studies are introduced. In Chapter 3, three neural model fitting equations are compared with the standard exponential model and hyperbolic model. The studies suggest the saturating-hyperbolic model fits better than the standard models when the reward magnitude is low ($10). The superiority of the saturating-hyperbolic model is even more robust when clinical populations are involved. However, the saturating-hyperbolic model does not fit the empirical data better than the standard models when the reward magnitude is high ($1000). In Chapter 4, cocaine users are compared with matched controls and with individuals with binge eating disorder on their delay discounting rates; the parameters are analyzed by the saturating-hyperbolic function. The results show that cocaine users do not have significantly higher delay discounting rates; rather, they have significantly higher saturation indices, indicating the observed decision making bias in cocaine users is associated with the decision factor related to reward utility instead of the decision factor related to time utility. Furthermore, the findings suggest the observed decision making bias in cocaine users is not associated with binge eating disorder, indicating the decision preference is likely to be specific to drug users. In Chapter 5, a personality measure based on the construct of time preference (the Time Preference Scale) is introduced. Its psychometric properties and its association with delay discounting and with the Barrat Impulsiveness Scale are investigated. The Time Preference Scale appears to have high reliability and validity. The latent trait of time preference is significantly associated with delay discounting rate. In addition, time preference is better than the overall score on the Barrat Impulsiveness Scale, but not better than the score on the non-planning subscale of the Barrat Impulsiveness Scale, in predicting the delay discounting rate. In Chapter 6, overall conclusions are drawn based on results of the current studies, and practice implications and research recommendations are provided.
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    Impulsivity and Risky Decision-Making
    (2016-05) Young, Nathaniel A
    The relationships between emotion, trait impulsivity, sensitivity to reward and punishment and risky decision-making were explored. Twenty-Seven undergraduate psychology students (14 males and 13 females) completed the (negative) Urgency, (lack of) Premeditation, (lack of) Perseverance, Sensation Seeking, and Positive Urgency scale (UPPS+P); the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ), and the Positive Affect and Negative Affect Schedule (PANAS). Afterward the participants performed the Iowa gambling task (IGT). Results showed that dimensions related to negative emotion and rash impulsivity significant factors within the model to predict risky decision-making during the IGT
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    Premorbid predictors of adolescent normative and problematic screen use: A longitudinal analysis of the Adolescent Brain Cognitive Development (ABCD) sample
    (2024-06) Hammel, Beatrice
    Aims: This study aims to assess whether premorbid individual differences in personality (impulsivity, reward sensitivity, and punishment sensitivity), psychopathology tendencies (internalizing and externalizing), and/or neurocognitive abilities (cognitive ability, executive function, and learning/memory) predict overall screen time (ST) versus problematic screen use (PSU) in mid-adolescence. The three research aims are to test whether late childhood individual differences longitudinally predict mid adolescent ST; to test predictiveness of mid adolescent PSU; and to test variation by screen activity. Method: Longitudinal data from 4,754 participants with released data at the baseline and year 4 waves of the Adolescent Brain Cognitive Development (ABCDTM) sample (Release 5.1) were used. Linear regression models tested whether impulsivity (UPPS-P), reward sensitivity (BAS Reward responsiveness + drive), punishment sensitivity (BIS), internalizing, externalizing (CBCL), and/or neurocognitive task performance at ages 9-10 predicted youth-reported ST or PSU of video games, social media, or smartphones at ages 12-15. Post-hoc analyses tested relative contributions of impulsivity sub- facets and replicability of PSU relationships when PSU was operationalized binarily. Results: Higher impulsivity and lower cognitive ability predicted longer video game ST in mid adolescence, and higher impulsivity and reward sensitivity predicted longer social media ST. Higher impulsivity predicted later PSU across screen activities. Higher punishment sensitivity and internalizing only predicted higher PSU of video games, and higher reward sensitivity only predicted higher PSU of phones. Conclusions: While impulsivity may underpin several forms of PSU, different risk factors among PSU of video games, social media, and smartphones suggest the use of different intervention strategies in the treatment of each behavior.
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    The Role of Transcranial Direct Current Stimulation and Cognitive Training to Decrease Food-Related Impulsivity Behavior in Individuals With Obesity: a Review and Pilot Study
    (2021-05) Salisbury, Madeleine
    Impulsivity has been implicated in refractory obesity. The dorsolateral prefrontal cortex (DLPFC) may counterbalance overactive brain reward by enhancing executive function (EF), including impulse control, mitigating loss-of-control eating. Galioto found that EF predicted weight-loss in structured medical weight-loss programs (Galioto 2016). Cognitive training (CT) monotherapy for EF improvement has not shown sufficient therapeutic promise nor has DLPFC-directed transcranial direct current stimulation (tDCS), but coupled, they may enhance EF. The aim of this study was to determine if tDCS coupled with computerized CT decreased impulsivity in individuals with obesity.
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    Towards a Translational Model of Decision-Making: Findings from the Web-Surf Task
    (2017-08) Abram, Samantha
    Interventions targeting cognitive disorders often hinge on assumptions that humans and nonhuman animals recruit equivalent cognitive mechanisms during decision- making. Identifying parallel decision systems across species could help bridge gaps between clinical and non-clinical research, and in turn, improve intervention efficacy. The goal of this dissertation is to assess for similar behavioral and neural markers of decision-making across humans and rodents using a sequential foraging paradigm (“The Web-Surf Task”) that was adapted from a rodent spatial neuroeconomic task (“Restaurant Row”). The included studies highlight a functional translational approach that aims to access similar functional constructs via parallel tasks and methodological approaches. The results provide evidence of cross-species behavioral equivalents, such as the ability to detect revealed preferences. Findings from a neuroimaging study suggest that different neural systems track past and forward representations, indicative of human prospection during deliberation (i.e., episodic future thinking). Moreover, neural activation related to difficult decisions is similar to many of the structures that underlie rodent deliberation. Lastly, a risk-variant of the task suggests that regret-instances provide a bridge between our liking and pursuit of rewards. This final study also finds that impulsive individuals may fail to learn from regret. Collectively, this dissertation demonstrates the utility of this novel task for elucidating human deliberative mechanisms and identifying cross-species decision system compatibilities.