Nondrug Reinforcement Loss and Relapse to Alcohol Seeking in Another Context

Extinguished alcohol-maintained responding has been shown to relapse in aresurgence preparation when food-reinforced responding is subsequently extinguished within the same context. However, drug and nondrug reinforcers are often specific to different contexts. Accordingly, the present experiments sought to determine whether loss of an alternative source of nondrug reinforcement in one context could produce relapse to drug seeking in a separate context. In one experiment, rats made topographically different responses for food or alcohol in alternating components of a multiple schedule. Both reinforcers were delivered during baseline, alcohol was withheld during the second phase of the experiment, and finally both reinforcers were withheld during the final phase. Extinguished alcohol-maintained responding increased upon discontinuation of food deliveries, but may have increased due to similarity between the final experimental phase and an initial training phase. In a second experiment, the training phase that complicated interpretation of the elevated responding observed in Experiment 1 was eliminated altogether. Alcohol seeking again relapsed upon discontinuation of food, suggesting that the training conditions were not the cause of the observed relapse in Experiment 1. Thus, loss of a nondrug reinforcer in one context can produce relapse to drug seeking in another. This procedure may provide a novel model of drug relapse in which loss of context-specific, alternative nondrug reinforcers precipitates relapse to drug seeking in a separate context

Selected Neuropharmacology of Resurgence

Resurgence refers to the reappearance of an extinguished operant behavior when reinforcement for an alternative behavior is also discontinued. It is especially relevant to the reappearance of problem behavior because many behavioral interventions discontinue reinforcement for aberrant behavior while simultaneously reinforcing an appropriate response. Existing information about the neuropharmacology of resurgence is scarce, but suggests overlap between drug seeking observed in the resurgence model and drug seeking observed in the more widely studied reinstatement and renewal models. The aim of this dissertation was to explore additional neural systems relevant to reinstatement and renewal preparations within a resurgence paradigm to assess further overlap. The neuropharmacology of resurgence was examined in two studies via administration of two drugs that have proven effective in blocking drug seeking in reinstatement and renewal preparations. In two experiments, rats earned food pellets for pressing a target lever in Phase I. In Phase II, lever pressing no longer produced food, but food was delivered contingent on an alterative nose poke response. Finally in Phase III, neither response produced food deliveries. Prior to these Phase III sessions, separate groups of rats were injected with 0, 50, or 100 mcg/kg of the dopamine D-2 receptor antagonist raclopride in Experiment 1 or 0, 20, or 40 mcg/kg of alpha-2 agonist clonidine in Experiment 2. Both doses of raclopride were effective in blocking resurgence, but there was strong evidence that the higher dose did so via motor rather than motivational impairment. Furthermore, the lower dose significantly suppressed the alternative nose poke, which suggests motor impairment, as well. Only the higher dose of clonidine blocked resurgence, but did so with no evidence of motor impairment. Raclopride significantly impacted extinction of the alternative poke at both doses tested, whereas clonidine had no effect at either dose. The results of the present studies provide additional information about the neuropharmacology of resurgence, as well as additional evidence of overlap between resurgence, reinstatement, and renewal. The present results may also have implications regarding underlying neural mechanisms and for pharmacotherapies to attenuate relapse when alternative sources of reinforcement are thinned or discontinued

Behavioral momentum and relapse of ethanol seeking: nondrug reinforcement in a context increases relative reinstatement

Drug-related stimuli seem to contribute to the persistence of drug seeking and relapse. Behavioral momentum theory is a framework for understanding how the discriminative-stimulus context in which operant behavior occurs governs the persistence of that behavior. The theory suggests that both resistance to change and relapse are governed by the Pavlovian stimulus-reinforcer relation between a stimulus context and all sources of reinforcement obtained in that context. This experiment examined the role of the Pavlovian stimulus-reinforcer relation in reinstatement of ethanol seeking of rats by including added response-independent nondrug reinforcement in the self-administration context. Although rates of ethanol-maintained responding were lower in a context with added nondrug reinforcement than a context with ethanol alone, relative resistance to extinction and relative reinstatement were greater in the context previously associated with the nondrug reinforcer. Thus, both relative resistance to extinction and relative relapse of ethanol seeking depended on the Pavlovian stimulus-reinforcer relation between a context and all sources of reinforcement in that context. These findings suggest that to understand how drug-related contexts contribute to relapse, it may be necessary to consider not only the history of drug reinforcement in a context, but also the wide variety of other reinforcers obtained in such contexts

Loss of Alternative Non-Drug Reinforcement Induces Relapse of Cocaine-Seeking in Rats: Role of Dopamine D1 Receptors

Animal models of relapse to drug seeking have focused primarily on relapse induced by exposure to drugs, drug-associated cues or contexts, and foot-shock stress. However, relapse in human drug abusers is often precipitated by loss of alternative non-drug reinforcement. The present experiment used a novel ‘resurgence' paradigm to examine relapse to cocaine seeking of rats as a result of loss of an alternative source of non-drug reinforcement. Rats were first trained to press a lever for intravenous infusions of cocaine. Next, cocaine deliveries were omitted and food pellets were provided for an alternative nose-poke response. Once cocaine seeking was reduced to low levels, food pellets for the alternative response were also omitted. Cocaine seeking increased with the loss of the alternative non-drug reinforcer (ie, resurgence occurred) despite continued extinction conditions. The increase in cocaine seeking did not occur in another group of rats injected with SCH 23390 before the loss of the alternative reinforcer. These results suggest that removal of an alternative source of reinforcement may induce relapse of cocaine seeking and that the dopamine D1 receptor may have a role in this effect

Unrealistic comparative optimism: An unsuccessful search for evidence of a genuinely motivational bias.

One of the most accepted findings across psychology is that people are unrealistically optimistic in their judgments of comparative risk concerning future life events-they judge negative events as less likely to happen to themselves than to the average person. Harris and Hahn (2011), however, demonstrated how unbiased (non-optimistic) responses can result in data patterns commonly interpreted as indicative of optimism due to statistical artifacts. In the current paper, we report the results of 5 studies that control for these statistical confounds and observe no evidence for residual unrealistic optimism, even observing a 'severity effect' whereby severe outcomes were overestimated relative to neutral ones (Studies 3 & 4). We conclude that there is no evidence supporting an optimism interpretation of previous results using the prevalent comparison method