| Summary: | 碩士 === 國立政治大學 === 心理學研究所 === 92 ===
By measuring of conditioned place preference (CPP) and conditioned locomotion, the present study manipulated various patterns of environment by composing three different contextual stimuli in the test chamber during different stages of conditioning to investigate behavioral processing and neural mechanisms underlying the association of conditioned stimulus and psychoactive drug. A relatively low dose of amphetamine (1.5 mg/kg) administered via intraperitoneal route was conducted as drug treatment throughout the study. In Experiment 1, the effects of CPP and conditioned locomotion were evaluated as different patterns of contextual stimuli composed in the test chamber presented during post-conditioning stage. The results showed CPP was significantly induced in the environment with context stimuli composed by at least two elements. And, the magnitude of conditioned locomotion induced by compound stimulus was higher than that induced by a single elemental stimulus. In Experiment 2, the effects of CPP and conditioned locomotion induced by a two-element compound stimulus were evaluated in the subjects received the drug pairing with both of each element stimulus in separate during the conditioning stage. The CPP was reliable induced by that compound stimulus. Although such CPP effect could also induced by an elemental stimulus specifically regarding to visual modality, it was not true for the other elemental stimulus manipulated on tactual modality. In Experiment 3, behavioral effects tested on the procedures of Experiment 2 were re-evaluated in the subjects received neurotoxic lesions in the amygdala, the dorsal hippocampus, or the ventral hippocampus before conditioning. While amygdaloid lesion significantly attenuated the CPP induced by elemental stimulus, such lesion did not inhibit the CPP induced by the compound stimulus. Lesions on those two hippocampal subareas disrupted the formation of CPP induced by compound stimulus. Regarding the conditioned locomotion, in contrast to what found on CPP, lesion treatment did not produce reliable effect induced by compound stimulus or elemental stimulus. In conclusion, the present findings on two conditioned responses measured support the assumption of Rescorla-Wagner Model on elemental theory. The lesion data indicate that amygdala and hippocampus are differentially involved in conditioned responses induced by psychoactive drug.
Key words: psychopharmacology, amphetamine, conditioned place preference, conditioned locomotion, elemental theory, configural theory, rat.
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