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Drug modulators in appetitive Pavlovian conditioning

Matthew I Palmatier, University of Nebraska - Lincoln


The widespread dependence on psychoactive drugs such as nicotine and amphetamine is a national public health problem. The main goal of the research in this dissertation was to explore an alternative model of subjective drug effects. Briefly, a conditional stimulus (CS) is followed by brief access to sucrose solution in a drug state (i.e., feature); no programmed outcome follows this CS in a no-drug (i.e., saline) state. As a result of this training, we expected the CS to evoke anticipatory sucrose seeking (i.e., goal tracking), but only in the drug state. ^ At least three drugs (0.4 mg/kg nicotine, 1 mg/kg amphetamine, and 5 mg/kg chlordiazepoxide) serve as signals for this CS-sucrose relation. Preliminary evidence suggested that this drug-state specific CR was not the result of dissociative drug effects (i.e., state-dependent learning). Moreover, changing the pharmacological properties of the drug state by substituting other doses or compounds attenuated conditional responding. Thus, rats acquired a CR that was specific to the pharmacological effects of the drug feature. ^ Notably, the drug feature perfectly predicts the sucrose outcome. Arguably, both the drug feature and CS may be associated with sucrose such that summation of excitatory conditioning of these two stimuli could also produce a drug-state specific CR. To test this possibility, each drug feature was repeatedly presented alone after training (i.e., extinction). This manipulation had no effect on performance of the drug-state specific CR. Thus, the drug state appears to modulate conditional responding independent of any excitatory association with sucrose. ^ Non-pharmacological stimuli that set the occasion for one CS-outcome relation can also set the occasion for responding to a CS with which it has never been presented. The last set of experiments in this dissertation established that rats could acquire drug-state specific goal tracking with two drugs and two target conditional stimuli. Moreover, when these concurrent discriminations were established, the drug features displayed transitive properties. Importantly, these transitive properties were not the result of non-specific or generalized conditional responding. ^

Subject Area

Psychology, Psychobiology|Psychology, Behavioral|Psychology, Physiological

Recommended Citation

Palmatier, Matthew I, "Drug modulators in appetitive Pavlovian conditioning" (2004). ETD collection for University of Nebraska - Lincoln. AAI3131555.