The abolition of the partial reinforcement extinction effect (PREE) by amphetamine

Abstract

The effects of amphetamine administration on the partial reinforcement extinction effect (PREE) at one trial a day, were examined. Two groups of rats were trained to run in a straight alley. The continuously reinforced (CRF) group received food reward on every trial. The partially reinforced (PRF) group was rewarded on a quasirandom 50% schedule. All animals were then tested in extinction. dl-Amphetamine 1.5 mg/kg was administered in a 2 X 2 design, i.e., drug-no drug in acquisition and drug-no drug in extinction. The PREE, i.e., increased resistance to extinction exhibited by PRF animals as compared to CRF animals, was obtained in animals that received saline in acquisition, independently of drug treatment in extinction. In contrast, amphetamine administered in acquisition abolished the PREE irrespective of drug treatment in extinction. In addition, amphetamine administered in extinction alone increased resistance to extinction in PRF animals.

Reversal and nonreversal shifts under amphetamine

“…In the PREE, partially reinforced animals exhibit subsequently retarded rate of extinction as compared to continuously reinforced animals. Both of these effects were abolished under amphetamine: stimulus-preexposed animals conditioned like their nonpreexposed controls (Solomon et al 1981;Weiner et al 1981Weiner et al , 1984 and partially reinforced animals did not show increased resistance to extinction as compared to continuously reinforced animals (Weiner et al 1985). These results suggest that in two-stage paradigms that involve a change in reinforcement contingencies from stage 1 to stage 2 and in which normal animals continue to respond in stage 2 according to reinforcement contingencies of stage 1, animals under amphetamine exhibit a rapid switch of responding according to the changed contingencies of stage 2.…”

The effects of clonidine on the partial reinforcement extinction effect (PREE)

“…Here it is of interest to note the effects of amphetamine on the PREE (Weiner et al 1985). Similarly to both clonidine and anxiolytics, the administration of amphetamine in acquisition alone disrupts the PREE by decreasing resistance to extinction in the PRF animals.…”

“…The tailing off technique was modelled after Feldon and Gray (1981a, Experiment 2). The gradual introduction of the drug was based on Weiner et al (1985). Both procedures served to prevent a drop in running speeds when animals are switched from drug to placebo or from placebo to drug at the start of extinction.…”

The effects of haloperidol on the partial reinforcement extinction effect (PREE): implications for neuroleptic drug action on reinforcement and nonreinforcement

“…The last 3 days of acquisition were used for gradually tailing off the drug in the Haloperidol-Placebo groups and gradually introducing the drug in the Placebo-Haloperidol groups. The gradual introduction of the drug was based on Weiner et al (1985) and the tniling off technique was modelled after Feldon and Gray (1981, experiment 2). Both procedures served to prevent a drop in running speeds when animals are first introduced to the drug at the start of acqisition or switched from drug to placebo or from placebo to drug at the start of extinction.…”

“…The PREE paradigm allows the assessment, within one experimental design, of drug actions on continuously reinforced, partially reinforced and nonreinforced behavior (extinction) following either CRF or PRF trainhag. In addition, we used a drug-no drug design (Weiner et al 1985), in which haloperidol was administered in acquisition only, in extinction only, in both stages, or in neither. This design has proven to be highly useful for elucidating the effects of various drugs on the PREE (Feldon and Gray 1981;Weiner et al 1985;Halevy et al 1986) as it allows us to evaluate separately the action of the drug in acquisition (CRF and PRF) and in extinction, as well as its combined action in both stages.…”