abstract: Smoking remains the leading cause of preventable death in the United States, and early initiation is associated with greater difficulty quitting. Among adolescent smokers, those with attention-deficit hyperactivity disorder (ADHD), characterized by difficulties associated with impulsivity, hyperactivity, and inattention, smoke at nearly twice the rate of their peers. Although cigarette smoking is highly addictive, nicotine is a relatively weak primary reinforcer, spurring research on other potential targets that may maintain smoking, including the potential benefits of nicotine on attention, inhibition, and reinforcer efficacy. The present study employs the most prevalent rodent model of ADHD, the spontaneously hypertensive rat (SHR) and its control comparison Wistar Kyoto (WKY) to examine the effects of acute and chronic subcutaneous nicotine injections on performance in three operant response inhibition paradigms. Functional activation in select regions of the prefrontal cortex and striatum was also explored. Acute (0.1, 0.3, 0.6 mg/kg) and chronic (0.3 mg/kg) nicotine increased impulsive responding regardless of strain, dose, or operant schedule. Dose-dependent decreases in latency to initiate the task were also observed. SHR receiving daily nicotine injections showed less activation in the nucleus accumbens shell compared to saline controls. Despite close similarities, one of the three operant tasks did not detect response inhibition deficits in SHR relative to WKY. A closer examination of these tasks may highlight critical components involved in the amelioration of response inhibition deficits. / Dissertation/Thesis / Doctoral Dissertation Psychology 2014

abstract: Delay discounting is the decline in the present value of a reward with delay to its receipt. (Mazur,1987). The delay discounting task is used to measure delay discounting rate, which requires the participants to choose between two options: one involves immediate delivery of a reward, and other involves delivery after a delay, and the immediate rewards are adjusted in value until the subject feels there is no difference between the immediate and the delayed reward. Some previous studies (Robles and Vargas, 2007; 2008; Robles et al., 2009) found that the order of presentation of the immediate rewards (ascending or descending) significantly influenced the estimated delay discounting rate, which is known as the order effect. Uncertainty about the future and impulsivity could explain delay discounting behavior. The purpose of this study was to explore the order effect in delay discounting assessment. The current study found that the order effect in the delay discounting task can be explained by risk aversion, loss aversion and impulsivity. In the current study, the two kinds of fixed procedure (ascending and descending), and the titrating delay discounting task were used to estimate the degree of delay discounting. Also, two gambling tasks were applied to measure risk and loss aversion indices. The BIS-11 scale was used to assess the level of trait impulsivity. The results indicated that impulsivity biases individuals to choose the immediate small reward rather than the large delayed reward, resulting in lower area under the discounting curve (AUC) when estimated with the ascending-sequence delay discounting task. Also, impulsivity moderated the relationship between loss aversion and AUC estimated with the descending-sequence delay discounting task. / Dissertation/Thesis / Masters Thesis Psychology 2018

Consuming alcohol may lead to negative consequences, such as aggression, violence or drunkdriving. However, not all adolescents who consume alcohol engage in negative behaviors.The purpose of this study was to examine the role of gender and impulsivity as risk factors forengagement in negative conducts after alcohol intoxication. The sample of this studycomprised 1,002 Swedish adolescent students between 12 and 16 years of age (52% boys). Students filled in self-report questionnaire at two time points (T1 and T2), once a year. Aftercontrolling for previous levels of negative consequences of alcohol consumption, as well asfor drinking habits at T1, the result showed that impulsivity had an impact on adolescent’salcohol-related consequences after intoxication. Also, boys showed a higher tendency toreport negative consequences after alcohol intoxication compared to girls. All in all, thislongitudinal study shed new light on the personality aspects that make adolescents more likelyto engage in negative conducts after alcohol consumption.

This thesis investigated the contribution of the nucleus accumbens core (AcbC) and the hippocampus (H) to choice and learning involving reinforcement that was delayed or unlikely. Animals must frequently act to influence the world even when the reinforcing outcomes of their actions are delayed. Learning with action-outcome delays is a complex problem, and little is known of the neural mechanisms that bridge such delays. Impulsive choice, one aspect of impulsivity, is characterized by an abnormally high preference for small, immediate rewards over larger delayed rewards, and is a feature of attention-deficit/hyperactivity disorder (ADHD), addiction, mania, and certain personality disorders. Furthermore, when animals choose between alternative courses of action, seeking to maximize the benefit obtained, they must also evaluate the likelihood of the available outcomes. Little is known of the neural basis of this process, or what might predispose individuals to be overly conservative or to take risks excessively (avoiding or preferring uncertainty, respectively), but risk taking is another aspect of the personality trait of impulsivity and is a feature of a number of psychiatric disorders, including pathological gambling and some personality disorders. The AcbC, part of the ventral striatum, is required for normal preference for a large, delayed reward over a small, immediate reward (self-controlled choice) in rats, but the reason for this is unclear. Chapter 3 investigated the role of the AcbC in learning a free-operant instrumental response using delayed reinforcement, performance of a previously learned response for delayed reinforcement, and assessment of the relative magnitudes of two different rewards. Groups of rats with excitotoxic or sham lesions of the AcbC acquired an instrumental response with different delays (0, 10, or 20 s) between the lever-press response and reinforcer delivery. A second (inactive) lever was also present, but responding on it was never reinforced. The delays retarded learning in normal rats. AcbC lesions did not hinder learning in the absence of delays, but AcbC-lesioned rats were impaired in learning when there was a delay, relative to sham-operated controls. Rats were subsequently trained to discriminate reinforcers of different magnitudes. AcbC-lesioned rats were more sensitive to differences in reinforcer magnitude than sham-operated controls, suggesting that the deficit in self-controlled choice previously observed in such rats was a consequence of reduced preference for delayed rewards relative to immediate rewards, not of reduced preference for large rewards relative to small rewards. AcbC lesions also impaired the performance of a previously learned instrumental response in a delay-dependent fashion. These results demonstrate that the AcbC contributes to instrumental learning and performance by bridging delays between subjects' actions and the ensuing outcomes that reinforce behaviour. When outcomes are delayed, they may be attributed to the action that caused them, or mistakenly attributed to other stimuli, such as the environmental context. Consequently, animals that are poor at forming context-outcome associations might learn action-outcome associations better with delayed reinforcement than normal animals. The hippocampus contributes to the representation of environmental context, being required for aspects of contextual conditioning. It was therefore hypothesized that animals with H lesions would be better than normal animals at learning to act on the basis of delayed reinforcement. Chapter 4 tested the ability of H-lesioned rats to learn a free-operant instrumental response using delayed reinforcement, and their ability to exhibit self-controlled choice. Rats with sham or excitotoxic H lesions acquired an instrumental response with different delays (0, 10, or 20 s) between the response and reinforcer delivery. H-lesioned rats responded slightly less than sham-operated controls in the absence of delays, but they became better at learning (relative to shams) as the delays increased; delays impaired learning less in H-lesioned rats than in shams. In contrast, lesioned rats exhibited impulsive choice, preferring an immediate, small reward to a delayed, larger reward, even though they preferred the large reward when it was not delayed. These results support the view that the H hinders action-outcome learning with delayed outcomes, perhaps because it promotes the formation of context-outcome associations instead. However, although lesioned rats were better at learning with delayed reinforcement, they were worse at choosing it, suggesting that self-controlled choice and learning with delayed reinforcement tax different psychological processes. Chapter 5 examined the effects of excitotoxic lesions of the AcbC on probabilistic choice in rats. Rats chose between a single food pellet delivered with certainty (probability p = 1) and four food pellets delivered with varying degrees of uncertainty (p = 1, 0.5, 0.25, 0.125, and 0.0625) in a discrete-trial task, with the large-reinforcer probability decreasing or increasing across the session. Subjects were trained on this task and then received excitotoxic or sham lesions of the AcbC before being retested. After a transient period during which AcbC-lesioned rats exhibited relative indifference between the two alternatives compared to controls, AcbC-lesioned rats came to exhibit risk-averse choice, choosing the large reinforcer less often than controls when it was uncertain, to the extent that they obtained less food as a result. Rats behaved as if indifferent between a single certain pellet and four pellets at p = 0.32 (sham-operated) or at p = 0.70 (AcbC-lesioned) by the end of testing. When the probabilities did not vary across the session, AcbC-lesioned rats and controls strongly preferred the large reinforcer when it was certain, and strongly preferred the small reinforcer when the large reinforcer was very unlikely (p = 0.0625), with no differences between AcbC-lesioned and sham-operated groups. These results suggest that the AcbC contributes to action selection by promoting the choice of uncertain, as well as delayed, reward.

Cognitive impairments and changes in the structure and function of related brain regions, namely the prefrontal cortex and striatum, have long been implicated in drug addiction. However, it is unknown whether these abnormalities predate substance abuse, potentially serving as risk factors for dependence, or if they are the consequence of protracted use. To address this question, endophenotype research using stimulant-dependent individuals’ biological siblings has been used to investigate traits implicated in the pathology of addiction. Impairments present in both groups suggest an underlying risk-state for dependence, while additional abnormalities present only in stimulant-dependent individuals reflect potential effects of the drugs themselves. Contrastingly, there are also individuals who use stimulant drugs in a controlled manner without developing dependence. These ‘recreational users’ may lack the underlying traits that comprise a greater risk for dependence, or they might maintain additional protective factors against the development of addiction. Experiments in the first half of this dissertation used functional magnetic resonance imaging to investigate neurocognitive similarities and differences between dependent stimulant users, their non-dependent siblings, recreational users of cocaine, and unrelated healthy control volunteers. In Chapter 2, performance on a colour-word Stroop task was impaired in both stimulant-dependent individuals and their siblings, suggesting an endophenotype of cognitive inefficiency. However, neural activity significantly differed between the groups, indicating additional changes specific to the use of stimulant drugs. In Chapter 3, dependent users showed significant attentional bias to salient stimuli on a cocaine-word Stroop task, with a concurrent increase in prefrontal activation. Conversely, recreational users showed resilience in the face of cocaine cues and a decrease in arousal. Finally, Chapter 4 explored differences in reward sensitivity to both generic and drug-specific reinforcers, comparing the effects of personal and family history of stimulant exposure on a monetary incentive delay task. It is also under debate whether the neurocognitive differences seen in stimulant-dependent individuals are unique to substance abuse, or if parallel changes in behaviour and neurobiology are present in similar addiction-spectrum disorders, such as binge eating leading to obesity. In Chapter 5, stimulant-dependent and obese individuals with binge-eating behaviours showed differences in their substance-specific and general reward responsivity on a novel reward-valuation task. However, in Chapter 6 a similar decline in orbitofrontal cortex grey matter volume in relation to both years of stimulant use and body mass index was identified, implicating an overlap in this area between both conditions. These findings are integrated in Chapter 7, discussing the neurocognitive risk and protective factors that underlie an individual’s vulnerability for addiction, not only to stimulant drugs, but also potentially for other addictive behaviours.

The current thesis examined the relationships between personality and attitudes and behaviours related to insurance claims, insurance fraud, and credit use. The thesis incorporates a systematic literature review of Impulsivity-related personality traits. This review led to the identification and development of a six factor framework of Impulsivity-related traits (Impetuousness, Self-Regulation, Deferred-Gratification, Consideration of Future Consequences or CFC, Attention, and Sensation Seeking). The framework was subsequently used to classify existing “Impulsivity” measures so that coherent review of research linking “Impulsivity” to financial behaviour could be undertaken. The framework guided review revealed that four Impulsivity-related traits (Impetuousness, Self-Regulation, Deferred-Gratification, CFC) appeared to be influential across a number of financial behaviours and as a result could be considered somewhat ‘central’ to financial behaviour. Accordingly, these four traits were assessed in each of the three empirical studies. In addition, each study also included a number of outcome specific traits. These were traits likely to be of importance to the specific outcome variables in each study but were unlikely to be related to economic behaviour across multiple domains. In Study 1 (n = 377), the central Impulsivity-related traits and the outcome specific traits of Compulsivity, Oppositionality, Risk-Taking, and Sensation Seeking were assessed in relation to Attitudes Towards Insurance Claims and the number of previously submitted motor and home insurance claims. The results revealed that Deferred-Gratification, CFC and Self-Regulation accounted for 36% of the variance in Attitudes Towards Insurance Claims, whilst a combined demographic, attitude and personality model was able to correctly classify participants as previous claimants or non-claimants in 84% of cases for motor claims and 66% of cases for home claims. In Study 2 (n = 475), the central Impulsivity-related traits and the outcome specific traits of Callousness, Conduct Problems, Dishonest-Opportunism, Integrity, Machiavellianism, and Pessimism were assessed in relation to Attitudes Towards Insurance Fraud and previously submitted motor and home insurance claims. The results revealed that Dishonest-Opportunism, Consideration of Future Consequences, Pessimism, Age and Educational Attainment accounted for 58% of the variance in Attitudes Towards Insurance Claims, whilst a combined demographic, attitude and personality model was able to correctly classify participants as previous claimants or non-claimants in 78% of cases for motor claims but did not predict home claims. In Study 3 (n = 611), the central Impulsivity-related traits and the outcome specific traits of Anxiety, Compulsivity, Insecure Attachment and Narcissism, were shown to be differentially predictive of five self-report financial behaviour factors (Irresponsible Spending, Financial Planning, Emotional Spending, Impulsive Credit Use and Poor Credit Management; 30-50% variance explained), the number of credit cards and loans owned (≈22% variance explained), and debt (11-15% variance explained). Finally, the personality traits were seated within a meditational model of: Personality → Credit Acquisition and Financial Behaviour → Debt. This model was strongly supported and accounted for 26% of the variance in loan debt and 31% of the variance in credit card debt.

Attention-deficit/hyperactivity disorder (ADHD) is characterized by hyperactivity, impulsive behavior, and excessive in attention. The diagnosis is divided into different types of ADHD depending on the symptoms. A single cause for the diagnosis has not been found; therefore, various models exist. When choosing between an immediate smaller reward and a later larger reward, ADHD-diagnosed individuals often choose the immediate smaller reward, termed choice impulsivity (CI). Several models have tried to explain this phenomenon. One theory argues that the subjective value of the reward diminishes when the reward is moved furtheraway in time. Others claim that it is a deficit in inhibitory-based executive dysfunction and that ADHD individuals cannot suppress the drive and resist the temptation of the earlier reward. The delay aversion model argues that it is a motivational problem with an abnormality in the reward mechanism making the patients hypersensitive to delayed rewards. The negative affective state that evokes from the delayed rewards makes them want to escape or avoid it and therefore choose the small, immediate reward. The insula and the amygdala mediate both negative and positive emotional processes in the brain and are candidates for this phenomenon. In this systematic review, four scientific studies were selected and included to investigate if the insula and amygdala are the primary CI candidates in ADHD-diagnosed individuals. The systematic review results support the idea that the amygdala correlates with CI in ADHD-diagnosed individuals, therefore supporting the delay aversion model theory of ADHD. A correlation between insula and CI in ADHD-diagnosed individuals could not be established in this systematic review. Understanding the role that emotional structures have in ADHD can help to develop interventions or therapy to cope with the disadvantaged features of ADHD.

Magister Educationis - MEd / Pupils experience various problems when trying to solve problems in Biology, particularly on Higher Grade. This problem was profound in the area of Homeostasis, an aspect of Human Physiology. During this investigation a number of pupils, the PIONEER GROUP, were screened for cognitive deficiencies. Major common deficiencies were identified as IMPULSIVITY, THE USE TWO OR MORE SOURCES OF INFORMATION SIMULTANEOUSLY, SPATIAL AND TEMPORAL ORIENTATION. A second phase, the essence of this investigation, sought ways in which to teach pupils the cognitive skills to facilitate their concept formation in the area of Homeostasis. Since the subjects displaying these cognitive deficiencies were already in their final year of High School a method was sought which would benefit them in the short term. Simultaneously a way had to be found to teach these skills so that it could be of use to pupils on a long term basis. This study revealed that for short term benefit the cognitive skills have to be subtly introduced and integrated with the subject content. Teaching cognitive skills in concentrated form over such a short period had a detrimental effect on the group subjected to this treatment. However, the PIONEER GROUP, had been taught these skills in a very short period in concentrated form. Feedback from them reveals that they were not able to apply the skills in their Senior Certificate Examination but all of them are now adept at using these skills to their benefit. This leads to the conclusion that if these skills are to be taught separately it should be started as early as possible in the school career. In the last year of High School it is more of a burden to the pupil than a benefit. In such a case it should be done integrated with subject content.

<p>Previous research has identified impulsive personality traits as significant risk factors for a wide range of risk-taking behavior, substance use, and clinical problems. Most work has been conducted in primarily White samples, leaving it unclear whether these patterns generalize to racial and ethnic minorities, who have higher rates of negative consequences of substance use behavior. The most widely used assessment of impulsive traits is the UPPS-P Impulsive Behavior scale, which has strong psychometric properties across demographic subgroups, such as gender and age; however, data supporting its use in racial and ethnic minorities is less well-developed. The aims of this study are to 1) examine the measurement invariance of the UPPS-P Impulsive Behavior Scale-Short Form (Cyders et al., 2014) across racial minority groups and 2) determine if impulsive personality traits differentially relate to substance use outcomes across racial groups. Participants were 1301young adults (ages 18-35, fluent in English), recruited through an online survey for both college students at a large public university and Mechanical Turk, a crowdsourcing online platform. Measurement invariance was assessed using multigroup confirmatory factor analysis. Differential validity was assessed using a structural equation modeling framework. I established model fit for each racial group (White group: RMSEA= .067, CFI= .94; Black group: RMSEA= .071, 90% CFI= .952; Asian American group: RMSEA= .073, CFI= .94; Hispanic group: RMSEA=.081, CFI=.934). Based on change in CFI/RMSEA indices, I concluded strong measurement invariance of the Short UPPS-P as a valid scale of impulsive behavior across racial groups. In the White group, findings indicated significant relationships between multiple SUPPS-P traits and alcohol and substance use. In the Asian American group, positive relationships were found between sensation and alcohol use (<i>p</i>=.015) and negative urgency and drug use (<i>p</i>=.020). I found that there were no differences in the relationships between the Short UPPS-P traits and substance use outcomes across White and the racial and ethnic groups studied (<i>p</i>’s>.06). </p>

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