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Typescript (photocopy). / Digitized by Kansas Correctional Industries

Motivation has been defined as a set of processes which enables organisms to overcome obstacles by energizing behavior in the pursuit of a goal. There are several important observations about motivated behavior which provide insight into the neural mechanisms underlying goal-directed motivation. First, motivation serves two important functions, as it both energizes behavior and also directs it toward or away from specific stimuli. Many of the behavioral tasks used to assay motivation in laboratory rodents do not specifically aim to measure these two distinct aspects of motivation. A second feature of goal-directed motivation is that it is sensitive to both costs and benefits of a given situation, enabling animals to make cost-benefit decisions. Again, many of the behavioral tasks which study cost-benefit decision making do not specifically aim to independently measure the impact of cost manipulations and benefit manipulations in an isolated manner. Here, I first develop behavioral measures which aim to specifically dissociate activational and directional effects of motivation. By characterizing a novel behavioral measure known as a Progressive Hold Down (Ph.D.) task, and using this task in parallel with a more traditionally used Progressive Ratio (PR) task, I show that methamphetamine robustly enhances activational effects of motivation, leading to increased response rates in both the Ph.D. and PR task, but mice are not more goal-directed in the Ph.D. task. I next develop and characterize two novel behavioral assays which are specifically used to examine effort and value contributions to cost-benefit decision making. The Concurrent Effort Choice (CEC) task measures how changes in effort levels impact decision making whereas the Concurrent Value Choice (CVC) task measure how changes in reward value impact decision making. Using these novel assays to examine specific processes important for goal-directed motivation, I carefully examine the role of manipulation of the Dopamine D2 receptor (D2R) in a mouse model which over-expresses the D2R within the striatum (D2R-OE), and the role of pharmacological manipulation of the Serotonin 2C receptor (5-HT2CR) with the functionally selective ligand SB242084. Whereas D2R-OE specifically impacts sensitivity to changes in effort levels which decrease overall levels of goal-directed motivation, selective modulation of the 5-HT2CR via treatment with SB242084 increases response vigor through enhanced dopamine release in the dorsomedial striatum, but this increase in response vigor does not alter sensitivity to effort or value changes when working for rewards. Together, these studies demonstrate the benefits of developing a more nuanced understanding of how specific manipulations impact motivated behavior by examining the specific underlying processes being altered.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 73-80).

Thesis (M.A.)--East Carolina University, 2009. / Presented to the faculty of the Department of Psychology. Advisor: Mark C. Bowler. Title from PDF t.p. (viewed June 11, 2010). Includes bibliographical references.

Dissertation (Ph.D.)--Auburn University, 2009. / Abstract. Includes bibliographic records (p.44-49).

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One fourth of students who enroll in 4-year universities never finish. Precipitating causes of early departure include poor academic progress and a lack of clear goals and motivation. A major cause of trouble adjusting to university is students’ failure to cognitively assimilate new experiences. Recent studies have demonstrated that goal setting leads to heightened well-being. Neuroscience research has also closely linked working memory (WM) and goal setting, because WM is related to the use of attention to activate information, for example, goal states or action plans. The present study investigated whether an intensive goal-setting program for struggling students who have experienced a substantial drop in performance would have positive effects not only on academic achievement, but also on well-being, personality (specifically conscientiousness and emotional stability), and cognitive functioning (specifically WM). Students (N = 101) experiencing subjectively perceived academic difficulty and a cumulative GPA ofless than 3.0 were recruited from McGill University. Participants completed baseline measures of mood, personality, and cognition, and were randomly assigned to one of two intervention groups: Half completed an intensive goal-setting program and half a control task with intervention-quality face validity. Every month for 4 months, students were retested on mood measures. After 4 months, students were retested on all measures. Official transcripts were gathered at the end of the semester subsequent to the intervention, in order to compare grades pre- and post-intervention as well as retention rates. [...] / Le quart des étudiants inscrit dans un programme universitaire ne termineront pas leurs études. Les causes qui précipitent cet abandon incluent une faible progression académique, un manque de motivation, ainsi qu’une absence de buts clairement établis. Une des raisons principales pouvant expliquer ce manque d’ajustement à la vie universitaire peut également s’expliquer par l’incapacité des étudiants à assimiler de nouvelles expériences sur le plan cognitif. Des études récentes ont démontré que se donner des objectifs aide à développer un sentiment accru de bien-être. La recherche neuroscientifique a aussi établi un lien étroit entre la mémoire de travail (MT) et la capacité de se fixer des objectifs. C’est à dire, la MT est reliée au déploiement des ressources attentionnelles, qui en retour sont importantes dans la planification et l’élaboration de stratégies pour faciliter l’atteinte d’un but ainsi que le retour sur l’état de ces buts. Cette étude vise à découvrir si l’utilisation d’un programme avec des objectifs claire peut avoir des bienfaits sur le plan académique, le bien-être, la personnalité (stabilité émotive et l’état de conscience) et le fonctionnement cognitif (MT) d’étudiants à faible rendement académique. Des étudiants (N = 101) en difficultés scolaires et ayant une note pondérée de moins de 3.0/4.0 ont été recrutés à l’Université McGill. Ceux-ci ont complété des tests mesurant leur bien-être, personnalité, fonctionnement cognitif et ont ensuite été assignés par hasard soit au groupe expérimental (assignation intensive d’objectifs) ou au groupe contrôle (intervention neutre apparaissant efficace). Chaque mois, pendant quatre mois, les étudiants ont rempli des questionnaires sur leur état émotionnel. [...]

In the theory of the Behavioral Inhibition System (BIS), Gray and McNaughton (2000) classified events that produce or inhibit goal-directed behaviour into two affective categories: approach versus avoidance. We experience goal-conflict when approximately equal but incompatible approach and avoidance tendencies are concurrently activated. Gray and McNaughton (2000) proposed goal-conflict as a class of mechanisms separable from "simple" mechanisms: Goal-conflict effects are maximal when incompatible approach and avoidance tendencies are balanced, simple effects are maximal when either approach or avoidance tendencies predominate. Gray and McNaughton (2000) saw the hippocampus as a key nexus for resolving goal conflict by recursive amplification of the subjective value of punishment, thereby increasing avoidance tendencies. Rodent hippocampal theta (4-12 Hz) is necessary (but not sufficient) for correct and efficient transmission of hipppocampal outputs. The BIS theory is fundamentally an animal model. It is not clear if a human BIS exists in the same form. Record human hippocampal (4-12 Hz) activity from the scalp is unlikely. However, during goal-conflict resolution, cortically generated theta recorded from the scalp could be modulated by human hippocampal theta. Therefore, superficially recorded 4-12 Hz theta spectra power was used to assess if specific goal-conflict processing activity could be detected in humans. Human goal-conflict processing was assessed in four experiments: the Stop-Signal Task (SST), an existing experimental task, and three variations of a task termed "Choice", created for this thesis. Across experiments, three key conditions were created. Approach and avoidance were balanced in the intermediate condition (maximal goal-conflict). Net approach and avoidance predominated in the adjacent conditions respectively (minimal goal-conflict). Goal-conflict was assessed as the difference between activity in the intermediate condition and the average activity across the adjacent conditions (via extraction of the orthogonal quadratic trend for significance testing). Goal-conflict increased activations consistently at F8, above the right frontal cortex. Increase in task dependent goal-conflict activations were also observed at F7, Fz and F4 above the frontal cortex, and T3, T4, T5 and T6 above the temporal cortex. Activations within the human theta frequency range (4-7 Hz) were consistently detected in the Choice tasks. In the SST, activations spanned the conventional human theta (4-7 Hz) and alpha (8-12 Hz) frequencies. In the Choice tasks, higher conflict theta at T3, T5 and F8 predicted increased avoidance. Taken together, the findings support Gray and McNaugthon�s (2000) views that a) goal-conflict is a class of mechanism separable from simple approach and avoidance; b) goal-conflict processing recruits and increases cortical rhythmic activity within the same frequency range as rodent hippocampal theta (4-12 Hz); and goal-conflict is resolved by increasing the subjective value of punishment, thereby increasing avoidance tendencies. Although speculative, the current work identified a right inferior frontal gyrus neural circuit for slower, and a presupplementary motor area circuit for faster behavioral inhibition during goal-conflict resolution. These circuits are not explicit in the current BIS model.

Thesis (MHlthSc(OccTh))--University of South Australia, 1999