No description available.

No description available.

The effect of post-training self-stimulation on associations formed during classical conditioning was studied. In the first three experiments, rats experienced tone-shock, tone-water and tone-light pairings, respectively. Control groups experienced the same situations except that the temporal relationship between the stimuli excluded the possibility of an association being formed. Following this training period, the experimental animals pressed a bar for electrical self-stimulation of the brain; control animals did not self-stimulate. Retention of the association between the training stimuli was evaluated by measuring conditioned suppression of drinking (experiments 1 and 3), or extinction of secondary reinforcement. The results showed that self-stimulation can retroactively and non-contingently improve memory for associations in various classical conditioning situations, independently of the presence of a natural reinforcer or of the responses they elicit. In another experiment, the effects of varying amounts of tone preexposure (latent inhibition) and of varying amounts of post-training self-stimulation on retention of a tone-shock association, measured by the amount of tone-induced suppression of drinking, were studied. Increasing amounts of tone pre-exposure produced decreased retention over all levels of self-stimulation, and increasing amounts of self-stimulation produced increased retention over all levels of pre-exposure. The interaction of these two factors suggests that they both acted on the strength of the tone-shock association: the pre-exposure acted proactively to weaken the association; the self-stimulation acted retroactively to strengthen it. The effect of delaying the post-training stimulation for various times after the tone-shock pairings was also investigated. Retention was improved by self-stimulation delayed for 15 or 30 minutes, but was not affected by self-stimulation delayed for an hour. These experiments suggest that direct activation

This thesis explored whether interpretations of the reinforcing effect of stimulation trains used in the self-administration of brain-stimulation (SABS) paradigm were artifacts of the reinforcement schedule chosen or whether it represented a genuine attempt by animals to maintain optimal levels of reward. Results demonstrate that stimulation trains used in SABS are reinforcing and that animals regulate pulse frequency to optimize the level of reward. The thesis then explored whether pedunculopontine tegmental nucleus (PPTg) lesions blocked the acquisition or maintenance of SABS, and the acquisition of eight-arm radial maze learning. Results showed that lesions confined to the PPTg block acquisition and maintenance of SABS, suggesting that the PPTg mediates the positive reinforcing effects of BSR. Further, PPTg lesions blocked win-shift and win-stay radial maze learning. However, results indicate that animals were not impaired in "shifting" or "staying" behavior. It is speculated that PPTg lesions block the reinforcing effects of food, which produce inefficient performance on both memory tasks.

There is no abstract available for this dissertation.

Typescript (photocopy) / xvii, 492 leaves : ill. (part col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--Dept. of Psychology, University of Adelaide, 1981

Thesis (M.A.)--University of Nevada, Reno, 2005. / "August, 2005." Includes bibliographical references (leaves 28-29). Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2005]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.

Thesis (M.App.Psy.)--University of Waikato, 2007. / Title from PDF cover (viewed March 19, 2008) Includes bibliographical references (p. 60-63)

Thesis (Ph.D.)--Dept. of Psychology, University of Adelaide, 1981. / Typescript (photocopy).

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 64-72). Also available on the Internet.