Renewal of operant performance formerly eliminated by omission or noncontingency training upon return to the acquisition context

A comparison of renewal, spontaneous recovery, and reacquisition after punishment and extinction

Punishment and extinction are both effective methods of reducing instrumental responding and may involve similar learning mechanisms. To characterize the similarities and differences between them, we examined three well-established recovery or "relapse" effects -renewal, spontaneous recovery, and reacquisition - following either punishment or extinction of an instrumental response. In Experiment 1a, both punished and extinguished responses renewed to similar degrees following a context change at test (ABA renewal). In Experiment 1b, responding spontaneously recovered to similar degrees following punishment or extinction. In Experiment 2, responding was rapidly reacquired when the response was reinforced again following extinction but not following punishment, as predicted by the idea that the reinforcer delivered in reacquisition is part of the context of punishment, but not extinction. The results collectively suggest that both punishment and extinction produce similar context-dependent retroactive interference effects. More broadly, they also suggest that punished and extinguished responses may be equally likely to return following a change of context despite the intuition that punishment might provide a more extreme and effective means of suppressing behavior. To our knowledge, this is the first direct behavioral comparison of response recovery after punishment and extinction within individual experiments.

Operant ABA renewal during dense and lean schedules of differential reinforcement

Renewal is a type of relapse that occurs due to a change in context. Previous research has demonstrated that renewal of target responding may occur despite the availability of differential reinforcement for an alternative response (DRA). Nevertheless, the current literature on renewal presents mixed findings regarding the effects of dense and lean schedules of DRA on the magnitude of renewal. We used a translational approach with undergraduate college students and a task on a touchscreen tablet device to study the effects of dense and lean schedules of DRA during repeated renewal tests. All participants experienced two, three-phase ABA renewal arrangements. In the dense and lean renewal arrangements, we differentially reinforced alternative behavior in Context B and the renewal test in Context A on a VI 3-s or a VI 12-s schedule, respectively. Overall, we observed renewal in 31/36 (86%) renewal tests regardless of the density of reinforcement for the alternative response. Furthermore, the results showed that although renewal occurred in both arrangements, we found slightly higher magnitudes of renewal during DRA with lean schedules of reinforcement relative to dense schedules. We discuss the implications of these findings as they relate to the treatment of problem behavior.

Learning to stop responding

Learning to stop responding is an important process that allows behavior to adapt to a changing and variable environment. This article reviews recent research in this laboratory and others that has studied how animals learn to stop responding in operant extinction, punishment, and feature-negative learning. Extinction and punishment are shown to be similar in two fundamental ways. First, the response-suppressing effects of both are highly context-specific. Second, the response-suppressing effects of both can be remarkably response-specific: Inhibition of one response transfers little to other responses. Learning to inhibit the response so specifically may result from the correction of "response error," the difference between the level of responding and what the current reinforcer supports. In contrast, the inhibition of responding that develops in feature-negative learning, where the response is reinforced during one discriminative stimulus (A) but not in a compound of A and stimulus B, is less response-specific: The inhibition of responding by stimulus B transfers and inhibits a second response, especially if the second response has itself been inhibited before. The results thus indicate both response-specific and response-general forms of behavioral inhibition. One possibility is that response-specific inhibition is learned when the circumstances encourage the organism to pay attention to the response-to what it is actually doing-as behavioral suppression is learned.

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.

Evaluating effects of context changes on resurgence in humans

Laboratory models of relapse provide methods for evaluating challenges to behavioral treatments with differential reinforcement of an alternative response (DRA). Resurgence occurs with the worsening of conditions of reinforcement for appropriate behavior and renewal occurs when transitioning out of a treatment context. Across five experiments, participants recruited via online crowdsourcing pressed onscreen buttons to earn points exchangeable for money and contexts sometimes changed through changes in the background image. Returning to the training context (ABA, Experiment 1) and transitioning to a novel context (ABC, Experiment 2) produced greater resurgence when removing alternative reinforcement in comparison with remaining in the treatment context (ABB). In contrast, we observed little difference in resurgence among AAA, ABB, and AAC context manipulations (Experiment 3) and ABA, ABC, and AAC context manipulations (Experiment 4). In Experiment 5, we evaluated relative contributions of the presence versus absence of context changes (ABA vs. ABB) in combination with or without the removal of alternative reinforcement. Both changing context and removing alternative reinforcement increased responding in isolation and the combination produced greater-than-additive effects. Overall, the present findings demonstrate a consistent effect of removing alternative reinforcement on relapse that, under certain conditions, can be enhanced by context change.

BEHAVIORAL AND NEUROBIOLOGICAL MECHANISMS OF PAVLOVIAN AND INSTRUMENTAL EXTINCTION LEARNING

This article reviews the behavioral neuroscience of extinction, the phenomenon in which a behavior that has been acquired through Pavlovian or instrumental (operant) learning decreases in strength when the outcome that reinforced it is removed. Behavioral research indicates that neither Pavlovian nor operant extinction depends substantially on erasure of the original learning but instead depends on new inhibitory learning that is primarily expressed in the context in which it is learned, as exemplified by the renewal effect. Although the nature of the inhibition may differ in Pavlovian and operant extinction, in either case the decline in responding may depend on both generalization decrement and the correction of prediction error. At the neural level, Pavlovian extinction requires a tripartite neural circuit involving the amygdala, prefrontal cortex, and hippocampus. Synaptic plasticity in the amygdala is essential for extinction learning, and prefrontal cortical inhibition of amygdala neurons encoding fear memories is involved in extinction retrieval. Hippocampal-prefrontal circuits mediate fear relapse phenomena, including renewal. Instrumental extinction involves distinct ensembles in corticostriatal, striatopallidal, and striatohypothalamic circuits as well as their thalamic returns for inhibitory (extinction) and excitatory (renewal and other relapse phenomena) control over operant responding. The field has made significant progress in recent decades, although a fully integrated biobehavioral understanding still awaits.

Cues Associated with Alternative Reinforcement During Extinction Can Attenuate Resurgence of an Extinguished Instrumental Response

In resurgence, a target behavior (R1) is acquired in an initial phase and extinguished in a second phase while an R2 behavior is reinforced. When R2 is extinguished, R1 behavior can return or resurge. Two experiments tested the effectiveness of a potential retrieval cue associated with extinction in attenuating resurgence. Experiment 1 established that a 2-s cue paired with outcome delivery in Phase 2 can attenuate resurgence when presented during testing. This effect depended on the cue being associated with the outcome, and it occurred if the cue was delivered contingently or noncontingently on responding during testing. Pairing the cue with reinforcement might be necessary to maintain attention to it during Phase 2. Experiment 2 demonstrated that the cue must be experienced in sessions that also include R1 extinction and that it does not reduce resurgence through a conditioned reinforcement mechanism. The results suggest that previously neutral stimuli can attenuate resurgence if they are first paired with alternative reinforcement and presented in sessions in which R1 is extinguished. They build on existing literature that suggests enhancing generalization between extinction and testing reduces resurgence. The results may have implications for reducing relapse following interventions in humans such as contingency management (CM), in which participants can earn vouchers contingent upon drug abstinence. A cue associated with CM might help reduce this relapse.

Relapse of operant behavior after response elimination with an extinction or an omission contingency

The present study compared relapse after responding was eliminated by extinction or omission training in rats. In Experiment 1, lever pressing was reinforced with food pellets in Context A and then eliminated with either extinction or omission training in Context B. The response was then tested in Contexts A and B in either the presence or absence of free food pellets delivered on a random time schedule. All rats showed higher responding when tested in Context A than Context B, and there was little evidence that omission training attenuated this ABA renewal effect. Noncontingent pellets increased responding after extinction but not after omission. However, when responding on the last day of response elimination was compared to responding during the test in the response-elimination context, there was some evidence that omission-trained rats showed a small increase in responding even when tested with free pellets. Results of Experiment 2 suggest this increase was not due to differences in the temporal distribution of pellets during elimination and the test, and that the result might be due to mere removal of the omission contingency, but any such effect is small and difficult to detect statistically. The results provide new information about factors generating relapse after omission training.

Extinction of instrumental (operant) learning: interference, varieties of context, and mechanisms of contextual control

This article reviews recent research on the extinction of instrumental (or operant) conditioning from the perspective that it is an example of a general retroactive interference process. Previous discussions of interference have focused primarily on findings from Pavlovian conditioning. The present review shows that extinction in instrumental learning has much in common with other examples of retroactive interference in instrumental learning (e.g., omission learning, punishment, second-outcome learning, discrimination reversal learning, and differential reinforcement of alternative behavior). In each, the original learning can be largely retained after conflicting information is learned, and behavior is cued or controlled by the current context. The review also suggests that a variety of stimuli can play the role of context, including room and apparatus cues, temporal cues, drug state, deprivation state, stress state, and recent reinforcers, discrete cues, or behaviors. In instrumental learning situations, the context can control behavior through its direct association with the reinforcer or punisher, through its hierarchical relation with response-outcome associations, or its direct association (inhibitory or excitatory) with the response. In simple instrumental extinction and habit learning, the latter mechanism may play an especially important role.

Renewal of extinguished operant behavior following changes in social context

Renewal is the reoccurrence of previously extinguished behavior following a change in the context in which extinction was conducted. Despite an extensive body of research examining renewal, little is known about the role of social stimuli in renewal. The present experiments provided a novel examination of renewal of operant behavior by changing social stimuli across phases in an ABA renewal preparation. In both experiments, social stimuli were arranged by placing another rat in a second compartment of a divided operant chamber. In Experiment 1, the presence of another rat defined the extinction context, whereas an empty second compartment defined the baseline and testing contexts. We reversed these contextual manipulations in Experiment 2 such that the presence of another rat defined the baseline and testing contexts and the second compartment was empty during extinction. Renewal of lever pressing occurred when the other rat was removed from the chamber in Experiment 1 and when the other rat was returned to the chamber in Experiment 2. Thus, social stimuli may function as contextual stimuli, and changes in social contexts may produce renewal of previously extinguished behavior.

Renewed behavior produced by context change and its implications for treatment maintenance: A review

Behavioral treatment gains established in one setting do not always maintain in other settings. The present review examines the relevance of basic and translational research to understanding failures to maintain treatment gains across settings. Specifically, studies of the renewal effect examine how transitioning away from a treatment setting could evoke a return of undesirable behavior, rather than newly trained appropriate behavior. Studies of renewal typically arrange three phases, with a response trained and reinforced under a particular set of contextual stimuli in the first phase. Next, that response is extinguished, often under a different set of contextual stimuli. Finally, that response returns despite extinction remaining in effect upon returning to the original training context or transitioning to a novel context. Thus, removing the extinction context is sufficient to produce a recurrence of the response. The findings suggest treatment effects can become specific to the context in which the treatment was delivered. This literature offers promising methods for systematically assessing the factors contributing to treatment maintenance and improving generalization of treatment gains across contexts. Therefore, the present review suggests basic and translational research on renewal provides an empirical literature to bring greater conceptual systematization to understanding generalization and maintenance of behavioral treatment.

Contextual control of operant behavior: evidence for hierarchical associations in instrumental learning

Recent research has suggested that operant responses can be weakened when they are tested in new contexts. The present experiment was therefore designed to test whether animals can learn a context-(R-O) relation. Rats were given training sessions in context A, in which one response (R1; lever pressing or chain pulling) produced one outcome (O1) and another response (R2; chain pulling or lever pressing) produced another outcome (O2) on variable interval reinforcement schedules. These sessions were intermixed with training in context B, where R1 now produced O2 and R2 produced O1. Given the arrangement, it was possible for the animal to learn two distinct R-O associations in each specific context. To test for them, rats were then given aversion conditioning with O2 by pairing its presentation with lithium-chloride-induced illness. Following the aversion conditioning, the rats were given an extinction test with both R1 and R2 available in each context. During testing, rats showed a selective suppression in each context of the response that had been paired with the reinforcer subsequently associated with illness. Rats could not have performed this way without knowledge of the R-O associations in effect in each specific context, lending support to the hypothesis that rats learn context-(R-O) associations. However, despite a complete aversion to O2, responding was not completely suppressed, leaving the possibility open that rats form context-R associations in addition to context-(R-O) associations.

Resurgence of instrumental behavior after an abstinence contingency

In resurgence, an extinguished instrumental behavior (R1) recovers when a behavior that has replaced it (R2) is also extinguished. The phenomenon may be relevant to understanding relapse that can occur after the termination of "contingency management" treatments, in which an unwanted behavior (e.g., substance abuse) is reduced by reinforcing an alternative behavior. When reinforcement is discontinued, the unwanted behavior might resurge. However, unlike most resurgence experiments, contingency management treatments also introduce a negative contingency, in which reinforcers are not delivered unless the client has abstained from the unwanted behavior. In two experiments with rats, we therefore examined the effects of adding a negative "abstinence" contingency to the resurgence design. During response elimination, R2 was not reinforced unless R1 had not been emitted for a minimum period of time (45, 90, or 135 s). In both experiments, adding such a contingency to simple R1 extinction reduced, but did not eliminate, resurgence. In Experiment 2, we found the same effect in a yoked group that could earn reinforcers for R2 at the same points in time as the negative-contingency group, but without the requirement to abstain from R1. Thus, the negative contingency per se did not contribute to the reduction in resurgence. These results suggest that the contingency reduced resurgence by making reinforcers more difficult to earn and more widely spaced in time. This could have allowed the animal to learn that R1 was extinguished in the "context" of infrequent reinforcement-a context more like that of resurgence testing. The results are thus consistent with a contextual (renewal) account of resurgence. The method might provide a better model of relapse after termination of a contingency management treatment.

Renewal of extinguished instrumental responses: independence from Pavlovian processes and dependence on outcome value

The source of renewal of instrumental responding in rats was investigated. In Experiment 1, two responses (R1 and R2) were reinforced with one outcome (O1) in contexts A and B (i.e., R1→O1, R2→O1), and then R2 was extinguished in A and R1 was extinguished in B. At test, the rate of R1 was higher than that of R2 in context A, and the reverse was the case in context B: Renewed responding was independent of the Pavlovian context→O1 associations. In Experiment 2, all rats received R1→O1 and R2→O2 trials in A and then were placed in B, where they were sated on O2 and either did (Group Extinction) or did not (Group No Extinction) receive concurrent extinction of R1 and R2. At test, we found more responding in A than in B for Group Extinction, but not for Group No Extinction, and the renewed responding in A was as sensitive to the current value of the outcome as responding that had not been subject to extinction (i.e., the rate was higher for R1 than for R2). That is, the renewed responding was goal-directed. These results identify the removal of contextual inhibion of either the response or the response→outcome associaon as potenal bases for renewal, and the response→outcome associaon as the source of renewed responding.

Why behavior change is difficult to sustain

Unhealthy behavior is responsible for much human disease, and a common goal of contemporary preventive medicine is therefore to encourage behavior change. However, while behavior change often seems easy in the short run, it can be difficult to sustain. This article provides a selective review of research from the basic learning and behavior laboratory that provides some insight into why. The research suggests that methods used to create behavior change (including extinction, counterconditioning, punishment, reinforcement of alternative behavior, and abstinence reinforcement) tend to inhibit, rather than erase, the original behavior. Importantly, the inhibition, and thus behavior change more generally, is often specific to the "context" in which it is learned. In support of this view, the article discusses a number of lapse and relapse phenomena that occur after behavior has been changed (renewal, spontaneous recovery, reinstatement, rapid reacquisition, and resurgence). The findings suggest that changing a behavior can be an inherently unstable and unsteady process; frequent lapses should be expected. In the long run, behavior-change therapies might benefit from paying attention to the context in which behavior change occurs.

Context-dependent savings in procedural category learning

Environmental context can have a profound influence on the efficacy of intervention protocols designed to eliminate undesirable behaviors. This is clearly seen in drug rehabilitation clinics where patients often relapse soon after leaving the context of the treatment facility. A similar pattern is commonly observed in controlled laboratory studies of context-dependent savings in instrumental conditioning, where simply placing an animal back into the original conditioning chamber can renew an extinguished instrumental response. Surprisingly, context-dependent savings in human procedural learning has not been carefully examined in the laboratory. Here, we provide the first known empirical demonstration of context-dependent savings in a perceptual categorization task known to recruit procedural learning. We also present a computational account of these savings using a biologically detailed model in which a key role is played by cholinergic interneurons in the striatum.

Context-induced relapse to alcohol seeking after punishment in a rat model

BACKGROUND

Rat studies have demonstrated that exposure to environments associated with alcohol intake reinstates alcohol seeking after extinction of alcohol-reinforced responding in a different context. However, extinction is limited as an abstinence model, because humans typically abstain because of negative consequences associated with excessive drinking. It is currently unknown whether alcohol-associated contexts can provoke relapse to alcohol seeking after alcohol-taking behavior is suppressed by adverse consequences in a different context.

METHODS

Alcohol-preferring P rats were first given home-cage access to 20% ethanol. Next, they were trained to self-administer 20% ethanol in one context (context A). Subsequently, all rats continued to self-administer alcohol in a different context (context B). For one group, 50% of alcohol-reinforced responses were punished by mild footshock; two other groups either received noncontingent shocks or no shock. A fourth group was given extinction training in context B. All rats were then tested for relapse to alcohol seeking under extinction conditions in contexts A and B.

RESULTS

In Context B, alcohol-taking behavior was suppressed by contingent shock (punishment) and extinction training but not by noncontingent shock. In Context A, relapse to alcohol seeking was reliably observed in the punished and extinction groups; a context switch had no effect on alcohol seeking in the no-shock or noncontingent shock groups.

CONCLUSIONS

Our data indicate that punishment-induced suppression of alcohol-taking behavior is context-dependent. We propose that our procedure can be used to explore mechanisms of context-induced relapse to alcohol seeking after alcohol-taking behavior is suppressed by adverse consequences.

Renewal after the extinction of free operant behavior

Four experiments were performed to explore the role of context in operant extinction. In all experiments, leverpressing in rats was first reinforced with food pellets on a variable interval 30-s schedule, then extinguished, and finally tested in the same and a different physical context. The experiments demonstrated a clear ABA renewal effect, a recovery of extinguished responding when conditioning, extinction, and testing occurred in contexts A, B, and A, respectively. They also demonstrated ABC renewal (where conditioning extinction and testing occurred in contexts A, B, and C) and, for the first time in operant conditioning, AAB renewal (where conditioning, extinction, and testing occurred in contexts A, A, and B). The latter two phenomena indicate that tests outside the extinction context are sufficient to cause a recovery of extinguished operant behavior and, thus, that operant extinction, like Pavlovian extinction, is relatively specific to the context in which it is learned. AAB renewal was not weakened by tripling the amount of extinction training. ABA renewal was stronger than AAB, but not merely because of context A's direct association with the reinforcer.

Learning and the persistence of appetite: extinction and the motivation to eat and overeat

The modern world is saturated with highly palatable and highly available food, providing many opportunities to associate food with environmental cues and actions (through Pavlovian and operant or instrumental learning, respectively). Basic learning processes can often increase the tendency to approach and consume food, whereas extinction, in which Pavlovian and operant behaviors decline when the reinforcer is withheld, weakens but does not erase those tendencies. Contemporary research suggests that extinction involves an inhibitory form of new learning that appears fragile because it is highly dependent on the context for expression. These ideas are supported by the phenomena of renewal, spontaneous recovery, resurgence, reinstatement, and rapid reacquisition in appetitive learning, which together may help explain why overeating may be difficult to suppress permanently, and why appetitive behavior may seem so persistent.

Renewal of sucrose-seeking behavior in rats: Role of D(2) dopamine receptors

The present study characterized renewal of sucrose-seeking behavior in rats (Experiment 1). The role of the dopamine subtype-2 (D(2)) receptors in mediating renewal of sucrose-seeking behavior also was examined (Experiment 2). Rats were trained to respond for sucrose pellets (45mg each) on a fixed-ratio 25 (Experiments 1 and 2) schedule of reinforcement in Context A. Following acquisition, rats underwent extinction and 4 renewal tests in Contexts B and A, respectively. In Experiment 2, rats were pretreated with vehicle or the D(2) dopamine receptor antagonist eticlopride (5, 10, 20, or 40microg/kg) 30min prior to the first renewal test session. A follow-up experiment (Experiment 3) examined the effect of a high eticlopride dose (40microg/kg) on locomotor activity. Renewal of sucrose-seeking behavior persisted for 3 sessions. Eticlopride dose-dependently blocked renewal of sucrose-seeking behavior without suppressing locomotor activity, implicating a role of D(2) dopamine receptors in mediating renewal of sucrose-seeking behavior.

Contextual renewal of cocaine seeking in rats and its attenuation by the conditioned effects of an alternative reinforcer

The present experiment investigated contextual renewal of cocaine seeking and potential methods of attenuating this renewal. Rats were first trained in one context to self-administer cocaine when a discriminative stimulus (tone) was presented. Then, the ABA Group was placed in a second context and responses in tone no longer produced cocaine (extinction). The AAA Group received this extinction in the original context. For two additional groups, responding to the tone was eliminated in a second context by additionally presenting food in tone according to a differential-reinforcement-of-other-behavior (DRO Group) schedule or independently of the rats' behavior on a fixed-time (FT Group) schedule. Renewal of responding to the tone was observed when the ABA Group was returned to the original context for a renewal test, but no renewal was observed in the AAA Group. Renewal also occurred in the DRO and FT Groups upon returning to the original context, but this renewal was significantly less than that of the ABA Group. These results suggest that response elimination techniques that are more active than simple extinction, such as pairing drug-related stimuli with alternative reinforcement, could reduce renewal of drug seeking and thereby help prevent relapse.

The neural correlates and role of D1 dopamine receptors in renewal of extinguished alcohol-seeking

We used an ABA renewal design to study the neural correlates, and role of D1 dopamine receptors, in contextual control over extinguished alcohol-seeking. Rats were trained to respond for 4% beer in one context (A), extinguished in a different (B) context, and then tested for responding in the original training context (A) or the extinction context (B). ABA renewal was mediated by D1 dopamine receptors because it was prevented by SCH23390. ABA renewal of alcohol-seeking was associated with selective increases in c-Fos protein induction in basolateral amygdala, ventral accumbens shell, and lateral hypothalamus (renewal-associated Fos). By contrast, being tested was associated with increased c-Fos induction in anterior cingulate, prelimbic and infralimbic cortex, rostral agranular insula, dorsomedial accumbens shell, and accumbens core (test-associated Fos). Renewal-associated Fos in ventral accumbens shell and lateral hypothalamus, but not basolateral amygdala, was D1 dopamine receptor dependent. Double immunofluorescence showed that renewal-associated Fos was expressed in orexin-negative lateral hypothalamic neurons. However, c-Fos induction in either lateral hypothalamic orexin-negative or orexin-positive neurons was positively and significantly correlated with alcohol-seeking. Test-associated c-Fos induction was observed in orexin-positive perifornical neurons. In both regions, c-Fos expression was dependent on D1 dopamine receptors. These results suggest that renewal of extinguished alcohol-seeking depends on a distributed neural circuit involving basolateral amygdala, ventral accumbens shell, and lateral hypothalamus that involves D1 dopamine receptors. Comparison with our previous results [Hamlin AS, Blatchford KE, McNally GP (2006) Renewal of an extinguished instrumental response: Neural correlates and the role of D1 dopamine receptors. Neuroscience 143:25-38] permits identification of similarities and differences in the correlates of renewal of extinguished drug- and natural-reward seeking.

Renewal of an extinguished instrumental response: Neural correlates and the role of D1 dopamine receptors

Contexts play an important role in controlling the expression of extinguished behaviors. We used an ABA renewal design to study the neural correlates, and role of D1 dopamine receptors, in contextual control over extinguished instrumental responding. Rats were trained to respond for a sucrose reward in one context (A). Responding was then extinguished in the same (A) or different (B) context. Rats were tested for responding in the original training context (A). Return to the original training context after extinction (group ABA) was associated with a return of responding. Three distinct patterns of Fos induction were detected on test: 1) ABA renewal was associated with selective increases in c-Fos protein induction in basolateral amygdala, ventral accumbens shell, and lateral hypothalamus (but not in orexin- or melanin-concentrating hormone (MCH)-hypothalamic neurons); 2) being placed in the same context as extinction training (AAA or ABB) was associated with a selective decrease in c-Fos induction in rostral agranular insular cortex; 3) being placed in any context on test was associated with the up-regulation of c-Fos induction in anterior cingulate, dorsomedial accumbens shell, accumbens core, lateral septum, and substantia nigra. The return of responding in ABA renewal was prevented by pre-treatment with the D1 dopamine receptor antagonist SCH23390 (10 microg/kg; s.c.). SCH23390 also suppressed basal and renewal-associated c-Fos protein induction throughout accumbens, and, selectively suppressed renewal-associated c-Fos induction in lateral hypothalamus. These results suggest that renewal of extinguished responding for a sucrose reward depends on a distributed neural circuit involving basolateral amygdala, ventral accumbens shell, and lateral hypothalamus. D1 dopamine receptors within this circuit are essential for renewal. The results also suggest that rostral agranular insular cortex may play an important role in suppressing reward-seeking after extinction training.

Resurgence of alcohol seeking produced by discontinuing non-drug reinforcement as an animal model of drug relapse

Findings from basic behavioral research suggest that simply discontinuing reinforcement for a recently reinforced operant response can cause the recurrence (i.e. resurgence) of a different previously reinforced response. The present experiment examined resurgence as an animal model of drug relapse. Initially, rats pressed levers to self-administer alcohol during baseline conditions. Next, alcohol self-administration was discontinued and non-drug reinforcers (food pellets) were presented contingent on an alternative response (chain pulling). Finally, when the non-drug reinforcer was discontinued, alcohol seeking recurred even though alcohol was still unavailable for lever pressing. These results suggest that simply discontinuing non-drug reinforcement for a behavior may be sufficient to produce relapse to drug seeking. The resurgence procedure could provide a method to examine environmental, pharmacological, and neurobiological factors that lead to relapse following the loss of a non-drug source of reinforcement.

Context switch effects on acquisition and extinction in human predictive learning

Four experiments tested context switch effects on acquisition and extinction in human predictive learning. A context switch impaired probability judgments about a cue-outcome relationship when the cue was trained in a context in which a different cue underwent extinction. The context switch also impaired judgments about a cue trained in a context different from the extinction context, whenever this training was concurrent with extinction of another cue. After extinction, new cue-outcome relationships learned, even in a different task, became context specific. Moreover, renewal was consistently observed. It is suggested that context switch effects result from a process by which ambiguity leads participants to attend to the contexts.