The involvement of dopamine in anticipatory and consummatory aspects of feeding behaviors was investigated in the present thesis. All measurements of dopaminergic activity were taken by in vivo electrochemical techniques. In Experiment 1, dopamine efflux in the nucleus accumbens and caudate of male rats was monitored during sessions in which a small, unsignalled liquid meal was consumed. Increases in the electrochemical measure of dopamine activity, which were of similar temporal pattern and magnitude, were observed in both the nucleus accumbens and striatum following meal consumption. These data suggest a possible postingestional role of dopamine in these two brain structures. In Experiment 2, a conditioned feeding paradigm was utilized to study the role of dopamine during a discrete anticipatory phase of feeding. Rats were conditioned to discriminate between a positive conditioned stimulus (CS+) predictive of meal delivery, and a negative conditioned stimulus (CS-) that was not associated with food. Increases in dopamine activity, as determined by changes in electrochemical oxidation currents, were found to be greater during the CS+ than during the CS- in both the nucleus accumbens and caudate. In addition, the magnitude of increase was greater in the nucleus accumbens than the caudate, suggesting that the accumbens may be preferentially involved in the processing of external incentive stimuli. The results support a role for dopamine in both the nucleus accumbens and caudate during appetitive or anticipatory responding for food in the male rat. / Medicine, Faculty of / Graduate

Text in English / In order to address the paucity of knowledge in regard to the psychological and physiological processes associated with lifelong weight loss (>20 years), this study adopts a qualitative approach informed by phenomenology to explore the experience of lifelong weight loss and maintenance of women who participated in the ITAND Programme. The research questions guiding the exploration of the current research are: (i) Which strategies from the ITAND Programme do women perceive as assisting with initial weight loss? (ii) What are the processes mediating lifelong weight loss? (iii) What strategies and skills mediate the maintenance of lifelong weight loss? (iv) What feelings or beliefs motivate women to continue attempts to lose weight after experiencing multiple failures on diets? and (v) Which psychological, cognitive and behavioural processes are identified as mediating lifelong weight loss? Eight overweight and obese women were invited to write their narratives and engage in interviews in regard to exploring their relationships with food, their bodies and their weight, after a period of more than 20 years following their participation in an integrative, transactional analysis, anti-diet programme (the ITAND Programme). Narratives were used to explore their beliefs about constructs, processes and strategies mediating long-term weight loss maintenance. The participants’ narratives and interviews were analysed through applying narrative analysis and interpretive phenomenological analysis. In addition to a non-diet paradigm, four processes definingweight loss maintenance were identified, including the adult learning process of transformative learning, the psychological process of transactional analysis, the physiological process of intuitive eating and the cognitive-behavioural processes relating to weight loss maintenance. This study contributes an integrative, transactional analysis, non-diet treatment model (ITAND model) which is enabled by the processes of transformative learning, intuitive eating and cognitive-behaviour modification to the successful long- term treatment of overweight and obesity. This model may be applied in whole or in part in a primary health care or community context. The findings of this study may be used to inform future research into the development and implementation of non-diet weight loss maintenance interventions in the treatment of overweight andobesity. / Psychology / D.Litt. et Phil. (Psychology)