Resurgence of punishment-suppressed cocaine seeking in rats

Resurgence of ethanol seeking following voluntary abstinence produced by nondrug differential reinforcement of other behavior

Resurgence refers to the relapse of a target behavior following the worsening of a source of alternative reinforcement that was made available during response elimination. Most laboratory analyses of resurgence have used a combination of extinction and alternative reinforcement to reduce target behavior. In contingency-management treatments for alcohol use disorder, however, alcohol use is not placed on extinction. Instead, participants voluntarily abstain from alcohol use to access nondrug alternative reinforcers. Inasmuch, additional laboratory research on resurgence following voluntary abstinence is warranted. The present experiment evaluated resurgence of rats' ethanol seeking following voluntary abstinence produced by differential reinforcement of other behavior (DRO). Lever pressing produced ethanol reinforcers during baseline phases. During DRO phases, lever pressing continued to produce ethanol and food reinforcers were delivered according to resetting DRO schedules. Ethanol and food reinforcers were suspended during resurgence test phases to evaluate resurgence following voluntary abstinence. Lever pressing was elevated during baseline phases and occurred at near-zero rates during DRO phases. During the resurgence test phases, lever pressing increased, despite that it no longer produced ethanol. The procedure introduced here may help researchers better understand the variables that affect voluntary abstinence from ethanol seeking and resurgence following voluntary abstinence.

A Comprehensive Systematic Review of Procedures and Analyses Used in Basic and Preclinical Studies of Resurgence, 1970-2020

Resurgence is the return of a previously reinforced response as conditions worsen for an alternative response, such as the introduction of extinction, reductions in reinforcement, or punishment. As a procedure, resurgence has been used to model behavioral treatments and understand behavioral processes contributing both to relapse of problem behavior and flexibility during problem-solving. Identifying existing procedural and analytic methods arranged in basic/preclinical research could be used by basic and preclinical researchers to develop novel approaches to study resurgence, whereas translational and clinical researchers could identify potential approaches to combating relapse during behavioral interventions. Despite the study of resurgence for over half a century, there have been no systematic reviews of the basic/preclinical research on resurgence. To characterize the procedural and analytic methods used in basic/preclinical research on resurgence, we performed a systematic review consistent with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). We identified 120 articles consisting of 200 experiments that presented novel empirical research, examined operant behavior, and included standard elements of a resurgence procedure. We reported prevalence and trends in over 60 categories, including participant characteristics (e.g., species, sample size, disability), designs (e.g., single subject, group), procedural characteristics (e.g., responses, reinforcer types, control conditions), criteria defining resurgence (e.g., single test, multiple tests, relative to control), and analytic strategies (e.g., inferential statistics, quantitative analysis, visual inspection). We make some recommendations for future basic, preclinical, and clinical research based on our findings of this expanding literature.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40614-022-00361-y.

Nondrug reinforcers contingent on alternative behavior or abstinence increase resistance to extinction and reinstatement of ethanol-maintained behavior

The effects of delivering nondrug alternative reinforcement on resistance to extinction and reinstatement of rats' ethanol-maintained lever pressing were evaluated in two experiments. In both, rats self-administered ethanol by lever pressing in a two-component multiple schedule during baseline. In the Rich component, alternative food reinforcement was made available for performing an alternative response (Experiment 1) or according to a differential-reinforcement-of-other-behavior schedule for lever pressing (Experiment 2). In the Lean component, only ethanol was available. Moreover, the frequency of alternative reinforcement was manipulated across conditions in Experiment 1. Following baseline, lever pressing was extinguished in both components by suspending ethanol reinforcement, and alternative food reinforcers were discontinued. Finally, to test for reinstatement, ethanol reinforcers were delivered independently of lever pressing in both components. In both experiments, proportion-of-baseline response rates were higher during extinction and reinstatement testing in the Rich component than in the Lean component (although differentiation was not observed at the lowest frequency of alternative reinforcement in Experiment 1). Thus, alternative nondrug reinforcers increased resistance to extinction and reinstatement of rats' ethanol-maintained lever pressing, even when those reinforcers were delivered contingently on an alternative response or on abstinence from lever pressing.

Effects of repeated exposure to escalating versus constant punishment intensity on response allocation

The present experiment investigated the effects of 1) repeated exposures to escalating punishment intensities and 2) repeated exposure to punishment after periods of vacation on response allocation between punished and unpunished responding in three groups of rats. The first group (intensity + vacation) experienced repeated exposures to escalating punishment intensities after a period of vacation (i.e., return to baseline) from punishment. The second group (intensity-only) experienced repeated exposures to escalating punishment intensities without vacation from punishment. The third group (vacation-only) experienced repeated exposures to a constant punishment intensity after a period of vacation from punishment. Results showed that superimposition of punishment on one of two concurrently available responses decreased allocation toward the punished response and increased allocation toward the unpunished response. Furthermore, greater changes in allocation were observed with the introduction of a moderate constant intensity than with the introduction of a low intensity that increased across sessions. Reexposure to punishment had different effects between the groups. Although there was evidence that high shock intensities can enhance the efficacy of lower intensities to shift allocation away from the punished response and toward the unpunished response, there was little evidence of changes in response allocation with reintroduction of punishment after a period of vacation.

Drug versus non-drug behaviors: A dual-reward model of sex differences and neurobiological mechanisms in rats

Substance Use Disorders (SUDs) are an impactful problem characterized by chronic relapse and engagement in drug-related behaviors at the expense of non-drug behaviors. Brain regions implicated in drug and non-drug-related behaviors often overlap, complicating investigations of neurobiological mechanisms underlying SUDs. Here we presented a within-subject model for studying self-administration, reinforcer competition, extinction, and cued reinstatement of cocaine- and food-seeking in rats. Due to differences in cocaine- and food-reinforced behavior, we transformed data to proportions of baseline, revealing increased resistance to extinction and disproportionately greater cued reinstatement of cocaine seeking relative to food seeking. Consistent with previous reports, females showed greater preference for cocaine reinforcement than males, though these findings failed to reach statistical significance. To demonstrate the model's utility for investigating neurobiological mechanisms, we included proof-of-concept calcium imaging data demonstrating the utility of the behavioral model for detecting cellular activity patterns associated with cocaine- and food-seeking behaviors. Future studies utilizing this model should improve understanding of the development and expression of pathological behaviors characteristic of SUDs in humans, sex differences in these behaviors, and their neurobiological correlates. Thus, the model has utility for improving understanding of SUDs, leading to novel treatments to reduce the pathological behaviors associated with SUDs.

Relapse after incentivized choice treatment in humans: A laboratory model for studying behavior change

Behavior change interventions that incentivize desired behavior are highly effective for improving personal health, but difficult to maintain long term. Relapse is common and examining the mechanisms that contribute to relapse in experimental settings can identify processes relevant to substance abuse treatment. We developed a laboratory task that parallels a recent operant model of relapse after incentivized choice reported in the rodent laboratory. In two experiments, undergraduate participants first learned to make an operant response (keyboard button; R1) to earn a reinforcer consisting of an image of a preferred snack food (O1). In a second phase (Phase 2), R1 was still reinforced, but a new response (R2) was introduced and reinforced with a different reinforcer (a coin; O2). In a test phase, contingent incentives for R2 were removed (extinction) and relapse of R1 was assessed. Experiment 1 found that the O2 contingency suppressed R1 during Phase 2, and R1 relapsed rapidly in the test. Neither effect was consistently related to O2 value. Experiment 2 examined whether noncontingent presentations of O1 or O2 during the test could weaken relapse. Here, we found that noncontingent reinforcers did little to reduce or slow the increase in R1 responding. The present experiments highlight a laboratory approach to studying variables that may influence relapse after incentivized treatment. We identify and discuss areas for development to address differences between the present results and prior observations from animal and clinical studies. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Circuit selectivity in drug versus natural reward seeking behaviors

Substance use disorder (SUD) is characterized, in part by behavior biased toward drug use and away from natural sources of reward (e.g., social interaction, food, sex). The neurobiological underpinnings of SUDs reveal distinct brain regions where neuronal activity is necessary for the manifestation of SUD-characteristic behaviors. Studies that specifically examine how these regions are involved in behaviors motivated by drug versus natural reward allow determinations of which regions are necessary for regulating seeking of both reward types, and appraisals of novel SUD therapies for off-target effects on behaviors motivated by natural reward. Here, we evaluate studies directly comparing regulatory roles for specific brain regions in drug versus natural reward. While it is clear that many regions drive behaviors motivated by all reward types, based on the literature reviewed we propose a set of interconnected regions that become necessary for behaviors motivated by drug, but not natural rewards. The circuitry is selectively necessary for drug seeking includes an Action/Reward subcircuit, comprising nucleus accumbens, ventral pallidum, and ventral tegmental area, a Prefrontal subcircuit comprising prelimbic, infralimbic, and insular cortices, a Stress subcircuit comprising the central nucleus of the amygdala and the bed nucleus of the stria terminalis, and a Diencephalon circuit including lateral hypothalamus. Evidence was mixed for nucleus accumbens shell, insular cortex, and ventral pallidum. Studies for all other brain nuclei reviewed supported a necessary role in regulating both drug and natural reward seeking. Finally, we discuss emerging strategies to further disambiguate the necessity of brain regions in drug- versus natural reward-associated behaviors.

Resurgence of alcohol seeking following abstinence induced by punishment in male and female rats

To better approximate the human condition, animal models of relapse to drug and alcohol seeking have increasingly employed negative consequences to generate abstinence. Here we report the first demonstration of relapse to punishment-suppressed alcohol seeking induced by loss of non-drug reward (i.e., resurgence). We also report the first examination of potential sex differences in any form of relapse to alcohol seeking following suppression by punishment. Male and female rats first pressed a lever for 20 % oral alcohol. Next, lever pressing for one group continued to produce alcohol, but also produced occasional footshock. For another group, lever pressing similarly produced alcohol and occasional footshock, and a nose-poke response produced alternative non-drug reward (i.e., food). Males showed similar suppression of alcohol seeking by punishment alone and punishment + alternative non-drug reward, whereas females showed less suppression by punishment alone. Finally, when alternative reinforcement and punishment were suspended, resurgence occurred for both sexes in the group that previously had access to non-drug reward. Exposure to and then removal of punishment alone did not produce relapse for males, but it did for females. These results suggest that loss of alternative non-drug reward can generate relapse to alcohol seeking following abstinence induced by negative consequences. Future research should further examine the role of potential sex differences in sensitivity to punishment and how such differences may contribute to relapse more broadly.

Effects of response cost magnitude on resurgence of human operant behavior

Extensive research has been dedicated to the study of resurgence following extinction and differential reinforcement of alternative behavior. Less is known about the effects of punishment on resurgence. This study extended previous research by examining whether the magnitude of response cost punishment affects resurgence of human operant behavior. College students engaged in a computer task using the three-phase resurgence procedure where points were used to reinforce target (Phase 1) or alternative (Phase 2) behavior. Across three groups, Phase 2 contingencies for the target response were manipulated. In one group, only extinction was implemented. In the other two groups, response cost was also implemented. Response cost was equal to or double the number of points that could be gained for alternative responding. Resurgence was similar in Phase 3 across the three groups, demonstrating that neither the addition nor the magnitude of punishment differentially affected response recovery under these conditions. Future research should examine other parameters of punishment (e.g., delay, schedule) and how these variables interact with different parameters of alternative reinforcement to increase our understanding of the conditions under which resurgence may be exacerbated or minimized.