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The psychostimulant effects of cocaine can be associated with environmental stimuli and thus can be easily conditioned in a laboratory setting. In rats, both behavioural stimulant and reinforcing effects of cocaine have been induced by presentation of stimuli previously paired with cocaine treatment. The stimulant locomotor response evoked by contextual stimuli is termed conditioned activity. It is hypothesized that haloperidol and the specific D3 receptor antagonist ABT-127 will produce a doubly dissociable effect on acquisition vs. expression of cocaine conditioned activity. Male rats received three 1-hr sessions of habituation to activity monitoring chambers (outfitted with infrared emitters and detectors), one session each day, over 3 days during which no drug was administered. The conditioning phase began on the next day and consisted of three 1-hr sessions, one every 48 hrs. Rats were pre-treated intraperitoneally (IP) with haloperidol (50 µg/kg) or ABT-127 (1 mg/kg) (or vehicle) 1 hr and 0.5 hr before being placed into the activity chambers, respectively, and with the indirect-acting dopamine agonist cocaine (10 mg/kg) or saline immediately before placement into the chambers. The expression phase took place 48 hrs following the last conditioning session. Animals received a single injection of haloperidol, ABT-127 (or vehicle) 1 hr or 0.5 hr prior to placement in the activity chambers and saline was administered immediately before. Analyses revealed a significant interaction of drug by phase. In agreement with my hypothesis, haloperidol given during the conditioning phase blocked the acquisition of conditioned activity but failed to block the expression of conditioning when given on the test day. In contrast, ABT-127, when given before cocaine during conditioning failed to block the acquisition of conditioned activity but blocked the expression of conditioning when administered on the test day. Results suggest that D2 receptors are necessary for acquisition but not initial expression and D3 receptors are required for expression but not acquisition of cocaine conditioned activity. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2007-09-19 01:00:11.058

The purpose of this study was to determine what effects a self-rewaard procedure involving the visualization of a pleasant scene had upon three operationally defined depressive behaviors. The three depressive behaviors were subjects' average self-confidence ratings, estimates of the rate of external reinforcement, and self-evaluations of their performance on a word association task. According to the self-reinforcement model of depression, a person becomes depressed as a result of a breakdown in any of the three stages, self-monitoring, self-evaluation, and self-reward of the self-reinforcement process. In an attempt to examine the role of self-rewards in modifying the three depressive behaviors, a high rate of self-rewarding behavior was used within a design previously utilized by Wener and Rehm (1975). Subjects in the self-reward treatment were hypothesized to manifest a statistical increase in the three depressive behaviors when compared to subjects in the no self-reward treatment. Furthermore, depressed subjects were hypothesized to be statistically lower on the three depressive behaviors than nondepressed subjects. Finally, no statistical difference on the three depressive behaviors was hypothesized when males were compared to females.Students in undergraduate psychology and general education courses at a Midwestern university were solicited as subjects for the study. A total of 380 students volunteered for the study and completed the Beck Depression Inventory (BDI). Based on their BDI scores, 96 subjects were selected with equal numbers of depressed and nondepressed, males and females. Just prior to the experimental procedure, subjects completed the BDI for a second time. Due to a shift in depression scores between initial and second presentations, 10 subjects were deleted from the study while another 11 subjects were deleted as a result of visualizing the self-rewarding scene when not requested thus changing the self-reward rate for the no self-reward treatment. The final sample size was 73.During the experimental procedure all subjects were asked to construct a pleasant scene based on their responses to the Reinforcement Survey Schedule while only the self-reward treatment subjects were requested to use the scene. After subjects gave a response to the cue word, they were asked how confident they were of their response. The other two dependent variables were obtained by asking, at the conclusion of the word association task, how well they felt they had done and how many times they were correct.Statistical processing of the data consisted of two, three-factor, non-orthogonal analyses of variance with the third factor (tester) blocked. All factors were reordered to determine their independent contribution. The first analysis eras multivariate in nature since both the average self-confidence rating and estimate of the rate of external reinforcement were used. The second analysis was univariate in nature since only self-evaluation was used. The use of a self-reward procedure involving the visualization of a pleasant scene was found to increase only subjects’ estimates of the rate of external reinforcement. No effects were found for average self-confidence ratings and self-evaluations. Thus, the self-reward procedure appeared to effect perceptions but not variables more centrally related to the self-concept, also, the self-reward procedure did not affect people in the same manner as external reinforcement. Depressed females had significantly lower self-confidence ratings and self-evaluations then nondepressed females, which lent support to the cognitive and self-reinforcement models of depression. Finally, as a result of a difference in depression levels between males and females, the validity of assuming males and females to express their depression in a similar manner was questioned.

The perception of reward is crucial in many psychological processes. Wise (1982) has suggested that the neurotransmitter dopamine is involved in producing 'hedonic' responses to rewards. Dopamine is also involved in the control of movement and hunger. Testing dopamine's role in reward perception is therefore complicated by these other actions; the effects of manipulations can often be interpreted as actions on hunger or motor control, rather than on reward. Two methods are described in this thesis which isolate reward effects. The effects of dopaminergic drugs on the rewarding impact of exploration were investigated. The use of exploration eliminates the influence of hunger, while the impact of motor deficits was reduced by using choice measures. Control experiments assessed effects on activity and emotionality. Results indicated that dopamine was involved in exploratory reinforcement independently of its roles in hunger or simple motor control. Tests of whether dopamine is involved in hedonia, or merely in engaging responses to reinforcers, used the 'behavioural contrast' paradigm. Contrast occurs when animals over-react to unexpected changes in reinforcement and allow response elicitation effects to be dissociated from effects on hedonia. Although the dopamine anatagonist a-flupenthixol did not affect contrast induced by changes in reinforcement value, the introduction or withdrawal of the drug could, itself, induce contrast effects. It is concluded that dopamine is involved in hedonia independently of any involvement in response elicitation. A speculative model of the nature of dopamine’s involvement in hedonia is proposed and its implications for our understanding of Parkinson’s disease and schizophrenia, in which dopamine dysfunctions are implicated, are discussed.

Both centrally and systemically administered dopamine agonists and antagonists decrease ingestive behaviour. The aim of this thesis was to examine whether drugs acting at different receptor subtypes decreased intake in different ways. A microstructural analysis was used to examine dopaminergic drug effects on licking behaviour. A dopamine D3 receptor agonist, 7-OH-DPAT, a dopamine D2 receptor antagonist raclopride and a mixed dopamine D2/D3 agonist quinpirole were compared in this paradigm. These drugs reduced the number of licks by differentially decreasing parameters which are thought to reflect the palatability of the stimulus such as mean bout duration of licking and the initial rate of licking. Follow-up experiments were conducted to further examine the possibility that motor deficits were underlying decreases in licking parameters. The effects of raclopride and 7-OH-DPAT were compared to the effects of a dopamine Dl antagonist SCH- 23390 and were analysed using a brief contact licking test. Again, the behavioural expression of anorexia induced by these drugs seemed to rely on a differential decrease in mean bout duration. Results also revealed that the three drugs used differed in the extent to which they produced a motoric deficit Attempts to block the effects of 7-OH-DPAT on licking (wameters were made by using the putative D3 receptor antagonists PNU-99194A and amisulpride. In addition, the effects of these drugs alone on licking behaviour were examined PNU-99194A failed to block the effects of 7-OH-DPAT and was relatively ineffective in producing changes in licking behaviour when administered alone. Amisulpride blocked the effects of 7-OH-DPAT only at high doses and when injected alone produced an increase in intake through an increase in mean bout duration of licking. Results from Chapters 4,5 and 6 suggested that 7-OH-DPAT was having an effect on palatability. Therefore, Chapter 7 presents an experiment which examines the effect of 7-OH-DPAT on the licking behaviour of rats which encounter a devaluation of reward (successive negative contrast). 7-OH-DPAT reduced successive negative contrast leading to the proposal that D3 receptors may mediate relative as well as absolute reinforcer value. These results bear important implications for understanding the role of dopamine receptor subtypes in components of food reward and appetitive behaviour in general and may well have implications for the treatment of eating disorders.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1972. / Bibliography: leaves [76]-80. / vii, 80 l tables

Thesis (Ph. D.)--Bob Jones University, 1987. / Abstract. Includes bibliographical references (leaves 390-398).

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed Mar. 31, 2009). PDF text: ix, 94 p. : ill. ; 910 K. UMI publication number: AAT 3330851. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (Ph. D.)--Westfälische Wilhelms-Universität zu Münster, 1972. / Vita. Includes bibliographical references (p. 290-329).

Thesis (M.A.)--Trinity Evangelical Divinity School, 1997. / Abstract. Includes bibliographical references (leaves 135-140).