A fundamental role for context in instrumental learning and extinction

Synthesized alternative reinforcement and resurgence

In treatments based on differential reinforcement of alternative behavior, applied researchers and clinicians often provide multiple, qualitatively different reinforcers (i.e., synthesized reinforcement) rather than a single reinforcer (i.e., isolated reinforcement) contingent on alternative behavior. Some research shows that providing synthesized reinforcement for alternative responses within such treatments produces more rapid and complete suppression of target behavior; however, there is limited research evaluating the durability of these effects during treatment disruptions. Conceptual explanations of resurgence (e.g., resurgence as choice, context theory) suggest that treatments that include synthesized alternative reinforcement may lead to more resurgence of target behavior when alternative reinforcement is disrupted relative to treatments using isolated reinforcement. We evaluated this hypothesis within a three-phase resurgence evaluation. We exposed rats to isolated or synthesized reinforcement for alternative responding in the second phase, and we exposed rats to extinction in the third phase. Synthesized alternative reinforcement produced more rapid and complete suppression of target behavior than did isolated reinforcement in the second phase; however, exposure to extinction following synthesized reinforcement produced more resurgence. We discuss these results in terms of their implications for applied research and their support for current conceptual explanations for resurgence.

Enhancing translation: A need to leverage complex preclinical models of addictive drugs to accelerate substance use treatment options

Preclinical models of addictive drugs have been developed for decades to model aspects of the clinical experience in substance use disorders (SUDs). These include passive exposure as well as volitional intake models across addictive drugs and have been utilized to also measure withdrawal symptomatology and potential neurobehavioral mechanisms underlying relapse to drug seeking or taking. There are a number of Food and Drug Administration (FDA)-approved medications for SUDs, however, many demonstrate low clinical efficacy as well as potential sex differences, and we also note gaps in the continuum of care for certain aspects of clinical experiences in individuals who use drugs. In this review, we provide a comprehensive update on both frequently utilized and novel behavioral models of addiction with a focus on translational value to the clinical experience and highlight the need for preclinical research to follow epidemiological trends in drug use patterns to stay abreast of clinical treatment needs. We then note areas in which models could be improved to enhance the medications development pipeline through efforts to enhance translation of preclinical models. Next, we describe neuroscience efforts that can be leveraged to identify novel biological mechanisms to enhance medications development efforts for SUDs, focusing specifically on advances in brain transcriptomics approaches that can provide comprehensive screening and identification of novel targets. Together, the confluence of this review demonstrates the need for careful selection of behavioral models and methodological parameters that better approximate the clinical experience combined with cutting edge neuroscience techniques to advance the medications development pipeline for SUDs.

Parietal-Frontal Pathway Controls Relapse of Fear Memory in a Novel Context

Background

Fear responses significantly affect daily life and shape our approach to uncertainty. However, the potential resurgence of fear in unfamiliar situations poses a significant challenge to exposure-based therapies for maladaptive fear responses. Nonetheless, how novel contextual stimuli are associated with the relapse of extinguished fear remains unknown.

Methods

Using a context-dependent fear renewal model, the functional circuits and underlying mechanisms of the posterior parietal cortex (PPC) and anterior cingulate cortex (ACC) were investigated using optogenetic, histological, in vivo, and ex vivo electrophysiological and pharmacological techniques.

Results

We demonstrated that the PPC-to-ACC pathway governs fear relapse in a novel context. We observed enhanced populational calcium activity in the ACC neurons that received projections from the PPC and increased synaptic activity in the basolateral amygdala-projecting PPC-to-ACC neurons upon renewal in a novel context, where excitatory postsynaptic currents amplitudes increased but inhibitory postsynaptic current amplitudes decreased. In addition, we found that parvalbumin-expressing interneurons controlled novel context-dependent fear renewal, which was blocked by the chronic administration of fluoxetine.

Conclusions

Our findings highlight the PPC-to-ACC pathway in mediating the relapse of extinguished fear in novel contexts, thereby contributing significant insights into the intricate neural mechanisms that govern fear renewal.

Isolation of the differential effects of chronic and acute stress in a manner that is not confounded by stress severity

Firm conclusions regarding the differential effects of the maladaptive consequences of acute versus chronic stress on the etiology and symptomatology of stress disorders await a model that isolates chronicity as a variable for studying the differential effects of acute versus chronic stress. This is because most previous studies have confounded chronicity with the total amount of stress. Here, we have modified the stress-enhanced fear learning (SEFL) protocol, which models some aspects of posttraumatic stress disorder (PTSD) following an acute stressor, to create a chronic variant that does not have this confound. Comparing results from this new protocol to the acute protocol, we found that chronic stress further potentiates enhanced fear-learning beyond the nonassociative enhancement induced by acute stress. This additional component is not observed when the unconditional stimulus (US) used during subsequent fear learning is distinct from the US used as the stressor, and is enhanced when glucose is administered following stressor exposure, suggesting that it is associative in nature. Furthermore, extinction of stressor-context fear blocks this additional associative component of SEFL as well as reinstatement of generalized fear, suggesting reinstatement of generalized fear may underlie this additional SEFL component.

Contribution of dorsal versus ventral hippocampus to the hierarchical modulation of goal-directed actions in rats

Adaptive behaviour often necessitates that animals learn about events in a manner that is specific to a particular context or environment. These hierarchical organisations allow the animal to decide which action is the most appropriate when faced with ambiguous or conflicting possibilities. This study examined the role of hippocampus in enabling animals to use the context to guide action selection. We used a hierarchical instrumental outcome devaluation task in which male rats learn that the context provides information about the unique action-outcome relations that are in effect. We first confirmed that rats encode and use hierarchical context-(action-outcome) relations. We then show that chemogenetic inhibition of ventral hippocampus impairs both the encoding and retrieval of these associations, while inhibition of dorsal hippocampus impairs only the retrieval. Importantly, neither dorsal nor ventral hippocampus was required for goal-directed behaviour per se as these impairments only emerged when rats were forced to use the context to identify the current action-outcome relationships. These findings are discussed with respect to the role of the hippocampus and its broader circuitry in the contextual modulation of goal-directed behaviour and the importance of hierarchical associations in flexible behaviour.

Adapting family-based treatment for adolescent anorexia nervosa delivered in the home: A novel approach for improving access to care and generalizability of skill acquisition

BACKGROUND

Anorexia nervosa (AN) is a serious mental illness associated with high rates of morbidity and mortality. Family-based treatment (FBT) is a well-established treatment for adolescent AN, yet it is underutilized in community settings and is unavailable to many families, particularly those from lower income and racial and ethnic minority backgrounds. Furthermore, some families do not respond optimally to FBT, possibly because of challenges translating skills acquired in office-based treatment settings to naturalistic settings. Home-based treatment could reduce barriers to access and enhance generalization of newly learned treatment skills. Home-based models demonstrate initial feasibility, acceptability, and efficacy for adolescent AN, however, FBT principles have yet to be applied as a stand-alone intervention in a home-based level of care. This paper describes the rationale for and process of adapting FBT principles/interventions to improve fit within a home-based model delivered in the context of community mental health, and discusses potential strengths and opportunities associated with this approach.

RESULTS

Adaptations were made through consultation with collaborating community agencies and were guided by the complex interventions framework. The primary modifications included: (1) altered dose; (2) multiple family meals; (3) additional support for meal preparation and supervision; (4) clinician attendance at medical appointments; (5) cultural adaptation; and (6) introduction of distress tolerance and emotion regulation skills.

CONCLUSIONS

Implementing FBT in the home may present one promising and novel approach to enhance engagement and treatment outcomes for adolescents with restrictive eating disorders, particularly those who are underserved, but evaluation of efficacy/effectiveness is needed.

Prelimbic cortex inactivation prevents ABA renewal based on satiety state

We have previously shown that the rat prelimbic cortex (PL) is necessary for contexts to promote the performance of instrumental behaviors that have been learned in them, whether the context is physical (operant chamber) or behavioral (recent performance of a behavior that has historically preceded the target in a behavior chain). In the present experiment, we investigated the role of the PL in satiety level as an interoceptive acquisition context. Rats were trained to lever-press for sweet/fat pellets while sated (22 hrs continuous food access) followed by the extinction of the response while hungry (22 hrs food deprived). Pharmacological inactivation of the PL (with baclofen/muscimol infusion) attenuated renewal of the response that occurred upon a return to the sated context. In contrast, animals that received a vehicle (saline) infusion showed renewal of the previously extinguished response. These results support the hypothesis that the PL monitors the relevant contextual elements (physical, behavioral, or satiety state) associated with reinforcement of a response and promotes the subsequent performance of that response in their presence.

The Situated Assessment Method (SAM2): Establishing individual differences in habitual behavior

From the perspectives of grounded, situated, and embodied cognition, we have developed a new approach for assessing individual differences. Because this approach is grounded in two dimensions of situatedness-situational experience and the Situated Action Cycle-we refer to it as the Situated Assessment Method (SAM2). Rather than abstracting over situations during assessment of a construct (as in traditional assessment instruments), SAM2 assesses a construct in situations where it occurs, simultaneously measuring factors from the Situated Action Cycle known to influence it. To demonstrate this framework, we developed the SAM2 Habitual Behavior Instrument (SAM2 HBI). Across three studies with a total of 442 participants, the SAM2 HBI produced a robust and replicable pattern of results at both the group and individual levels. Trait-level measures of habitual behavior exhibited large reliable individual differences in the regularity of performing positive versus negative habits. Situational assessments established large effects of situations and large situation by individual interactions. Several sources of evidence demonstrated construct and content validity for SAM2 measures of habitual behavior. At both the group and individual levels, these measures were associated with factors from the Situated Action Cycle known to influence habitual behavior in the literature (consistency, automaticity, immediate reward, long-term reward). Regressions explained approximately 65% of the variance at the group level and a median of approximately 75% at the individual level. SAM2 measures further exhibited well-established interactions with personality measures for self-control and neuroticism. Cognitive-affective processes from the Situated Action Cycle explained nearly all the variance in these interactions. Finally, a composite measure of habitualness established habitual behaviors at both the group and individual levels. Additionally, a composite measure of reward was positively related to the composite measure of habitualness, increasing with self-control and decreasing with neuroticism.

Intermittent access cocaine self-administration produces context-specific escalation and increased motivation

The intermittent-access (IntA) self-administration procedure has been reported to produce intensified addiction-like behavior compared to continuous-access (ContA) procedures. In a common variation of the IntA procedure, cocaine is available for 5 min at the beginning of each half hour of a 6-h session. In contrast, during ContA procedures, cocaine is available continuously throughout a session, typically lasting one or more hours. Previous studies comparing procedures have used between-subjects designs, where separate groups of rats self-administer cocaine on either IntA or ContA procedures. The present study used a within-subjects design where subjects self-administered cocaine on the IntA procedure in one context and self-administered cocaine on the continuous short-access (ShA) procedure in another context during separate sessions. Across sessions, rats escalated cocaine intake in the IntA, but not ShA, context. Following sessions eight and 11, rats were administered a progressive ratio test in each context to monitor the change in cocaine motivation. Rats obtained more cocaine infusions on the progressive ratio test in the IntA context than in the ShA context following 11 sessions. These results suggest that addiction-like behaviors following IntA self-administration may be influenced by context-specific learning factors.

Motivational state-dependent renewal and reinstatement of operant responding under food and water deprivation states

Most studies of operant relapse phenomena have studied the role of exteroceptive discriminative features of context in the recovery of behavior after extinction. Interoceptive stimuli (i.e., stimuli arising from the bodies of organisms) may also serve as a part of learning contexts and contribute to relapse. Recent studies have demonstrated that events that function as motivating operations (MOs) may contribute to relapse both by a) eliciting interoceptive conditions that serve as a discriminative context for relapse (i.e., discriminative function) and b) altering the amount of operant responding in the presence of discriminative stimuli associated with reinforcers (i.e., motivational function). The current study examined interactions between these functions of food and water deprivation MOs in the relapse of operant behavior. During acquisition of an operant response, one group of mice was food-deprived and another was water-deprived. The groups then received extinction sessions under the opposite condition. Renewal and reinstatement tests were conducted under both conditions, and more renewal and reinstatement were observed in the motivational states in which acquisition occurred for each. These results are discussed in the context of state-dependent learning.

Habit formation in context: Context‐specific and context‐free measures for tracking fruit consumption habit formation and behaviour

OBJECTIVES

Interventions promoting habitual fruit consumption have the potential to bring about long-term behaviour change. Assessing the effectiveness of such interventions requires adequate habit and behaviour measures. Habits are based on learned context-behaviour associations, so measures that incorporate context should be more sensitive to expected habit and behaviour changes than context-free measures. This study compared context-specific and context-free measures of fruit consumption habit and behaviour following a 3-week habit formation intervention.

DESIGN

Prospective online study (n = 58).

METHODS

Behaviour frequency was assessed across five timepoints, retrospectively (Time 1 [T1], T5) or via daily diary data (uploaded weekly at T2, T3 and T4). Habit strength was assessed before (T1) and immediately after the intervention (T4), and again 2 weeks later (T5). Analyses of variance were run, with time and context specificity as within-subject factors, and habit and behaviour frequency as dependent measures.

RESULTS

An interaction between time and context specificity was found in both analyses (habit: F(2,114) = 12.848, p < .001, part.η²  = .184; behaviour: F(2,114) = 6.714, p = .002, part.η²  = .105). Expected habit formation patterns 5 weeks post-baseline were only detected by the context-specific habit measure. Likewise, increased behaviour frequency was only found when the target context was specified (p's < .001).

CONCLUSIONS

Assessments of purposeful dietary habit and behaviour change attempts should incorporate context-specific measurement.

Implementation and outcomes of home-based treatments for adolescents with anorexia nervosa: Study protocol for a pilot effectiveness-implementation trial

OBJECTIVE

Although family-based treatment (FBT) is considered a first-line treatment for adolescent anorexia nervosa (AN), it is underutilized in community settings and is unavailable to many families for a multitude of practical reasons (e.g., costs of treatment, transportation constraints). Adapting FBT interventions for delivery in home-based and community-based settings may reduce pragmatic barriers to treatment uptake and engagement.

METHODS

This pilot effectiveness-implementation trial will assess outcomes, implementation, and mechanisms of FBT adapted for the home setting (FBT-HB), delivered in the context of community-based behavioral health agencies. Adolescents with AN-spectrum disorders (n = 50) and their caregivers will be randomly assigned to either FBT-HB or home-based treatment as usual (TAU; integrated family therapy approach). Caregivers and adolescents will provide data on weight, eating, and putative treatment mechanisms, including caregiver self-efficacy and adolescent eating-related and weight-related distress. Implementation constructs of feasibility, acceptability, and appropriateness will be measured among providers and participating families.

HYPOTHESES

We expect that FBT-HB will be feasible, acceptable, and appropriate, and will outperform TAU in terms of improvements in adolescent weight and eating-related psychopathology. We further expect that caregiver self-efficacy and adolescent eating-related and weight-related distress, but not general distress, will show greater improvements in FBT-HB relative to TAU and will be associated with better adolescent weight and eating outcomes in FBT-HB.

POTENTIAL IMPLICATIONS

The proposed study has clear potential to advance scientific and clinical understanding of the real-world effectiveness of FBT for AN, including whether adapting it for the home setting improves its accessibility and effects on treatment outcome.

Saliency determines the integration of contextual information into stimulus-response episodes

When humans perform a task, it has been shown that elements of this task, like stimulus (e.g., target and distractor) and response, are bound together into a common episodic representation called stimulus–response episode (or event file). Recently, the context, a completely task-irrelevant stimulus, was found to be integrated into an episode as well. However, instead of being bound directly with the response in a binary fashion, the context modulates the binary binding between the distractor and response. This finding raises the questions of whether the context can also enter into a binary binding with the response, and if so, what determines the way of its integration. In order to resolve these questions, saliency of the context was manipulated in three experiments by changing the loudness (Experiment 1) and emotional valence (Experiment 2A and 2B) of the context. All experiments implemented the four-alternative auditory negative priming paradigm introduced by Mayr and Buchner (2006, Journal of Experimental Psychology: Human Perception and Performance, 32[4], 932–943). Results showed that the integration of context changed as a function of its saliency level. Specifically, the context of low saliency was not bound at all, the context of moderate saliency modulated the binary binding between the distractor and response, whereas the context of high saliency entered into a binary binding with the response. The current results extend a previous finding by Hommel (2004, Trends in Cognitive Sciences, 8[11], 494–500) that there is a saliency threshold which determines whether a stimulus is bound or not, by suggesting that a second threshold determines the specific structure (i.e., binary vs. configural) of the resulting binding.

Indoor or outdoor? Generalization of costly pain-related avoidance behavior to conceptually related contexts

When pain persists beyond healing time and becomes a "false alarm" of bodily threat, protective strategies, such as avoidance, are no longer adaptive. More specifically, generalization of avoidance based on conceptual knowledge may contribute to chronic pain disability. Using an operant robotic-arm avoidance paradigm, healthy participants (N=50), could perform more effortful movements in the threat context (e.g. pictures of outdoor scenes) to avoid painful stimuli, whereas no pain occured in the safe context (e.g. pictures of indoor scenes). Next, we investigated avoidance generalization to conceptually related contexts (i.e. novel outdoor/indoor scenes). As expected, participants avoided more when presented with novel contexts conceptually related to the threat context than in novel exemplars of the safe context. Yet, exemplars belonging to one category (outdoor/indoor scenes) were not interchangeable; there was a generalization decrement. Posthoc analyses revealed that contingency-aware participants (n=27), but not non-aware participants (n=23), showed the avoidance generalization effect and also generalized their differential pain-expectancy and pain-related fear more to novel background scenes conceptually related to the original threat context. In contrast, the fear-potentiated startle response was not modulated by context.

When Do We Not Face Our Fears? Investigating the Boundary Conditions of Costly Pain-Related Avoidance Generalization

Excessive generalization of fear and avoidance are hallmark symptoms of chronic pain disability, yet research focusing on the mechanisms underlying generalization of avoidance specifically, is scarce. Two experiments investigated the boundary conditions of costly pain-related avoidance generalization in healthy participants who learned to avoid pain by performing increasingly effortful (in terms of deviation and force) arm-movements using a robot-arm (acquisition). During generalization, novel, but similar arm-movements, without pain, were tested. Experiment 1 (N = 64) aimed to facilitate generalization to these movements by reducing visual contextual changes between acquisition and generalization, whereas Experiment 2 (N = 70) aimed to prevent extinction by increasing pain uncertainty. Both experiments showed generalization of pain-expectancies and pain-related fear. However, Experiment 2 was the first and only to also demonstrate generalization of avoidance, ie, choosing the novel effortful arm-movements in the absence of pain. These results suggest that uncertainty about the occurrence of pain may delay recovery, due to reduced disconfirmation of threat beliefs when exploring, resulting in persistent avoidance. PERSPECTIVE: This article demonstrates generalization of instrumentally acquired costly pain-related avoidance in healthy people under conditions of uncertainty. The results suggest that targeting pain-related uncertainty may be a useful tool for clinicians adopting a psychological approach to treating excessive pain-related avoidance in chronic pain.

Calcineurin Participation in Hebbian and Homeostatic Plasticity Associated With Extinction

In nature, animals need to adapt to constant changes in their environment. Learning and memory are cognitive capabilities that allow this to happen. Extinction, the reduction of a certain behavior or learning previously established, refers to a very particular and interesting type of learning that has been the basis of a series of therapies to diminish non-adaptive behaviors. In recent years, the exploration of the cellular and molecular mechanisms underlying this type of learning has received increasing attention. Hebbian plasticity (the activity-dependent modification of the strength or efficacy of synaptic transmission), and homeostatic plasticity (the homeostatic regulation of plasticity) constitute processes intimately associated with memory formation and maintenance. Particularly, long-term depression (LTD) has been proposed as the underlying mechanism of extinction, while the protein phosphatase calcineurin (CaN) has been widely related to both the extinction process and LTD. In this review, we focus on the available evidence that sustains CaN modulation of LTD and its association with extinction. Beyond the classic view, we also examine the interconnection among extinction, Hebbian and homeostatic plasticity, as well as emergent evidence of the participation of kinases and long-term potentiation (LTP) on extinction learning, highlighting the importance of the balance between kinases and phosphatases in the expression of extinction. Finally, we also integrate data that shows the association between extinction and less-studied phenomena, such as synaptic silencing and engram formation that open new perspectives in the field.

The DA-antagonist Tiapride affects context-related extinction learning in a predictive learning task, but not initial forming of associations, or renewal

Renewal describes the recovery of an extinguished response if the contexts of extinction and recall differ, highlighting the context dependency of extinction. Studies demonstrated dopaminergic (DA) signalling to be important for context-related extinction learning with and without a fear component. In a previous study in humans, administration of the dopamine D2/D3 antagonist tiapride prior to extinction impaired extinction learning in a novel, but not a familiar context, without affecting renewal. In a further study, context processing during initial acquisition of associations was shown to be related to renewal. In this human fMRI study we investigated the potential role of DA signalling during this initial conditioning for the learning process and for renewal. While tiapride, administered prior to the start of learning, did not affect initial acquisition and renewal, extinction learning in a novel context was impaired, associated with reduced BOLD activation in vmPFC, left iFG and ACC - regions mediating response inhibition and selection from competing options using contextual information. Thus, different timepoints of administration of tiapride (before initial conditioning or extinction) had largely similar effects upon extinction and renewal. In addition, retrieval of previously acquired associations was impaired, pointing towards weaker association forming during acquisition. Conceivably, effects of the DA blockade are associated with the challenge present in the respective task rather than the administration timepoint: the cognitive flexibility required for forming a new inhibitory association that includes a novel element clearly requires DA processing, while initial forming of associations, or of inhibitory associations without a new element, apparently rely less on the proper function of the DA system.

Stimulus-Based Extinction Generalization: Neural Correlates and Modulation by Cortisol

BACKGROUND

While healthy individuals and patients with anxiety disorders easily generalize fear responses, extinction learning is more stimulus specific. Treatments aiming to generalize extinction learning are urgently needed, since they comprise the potential to overcome stimulus specificity and reduce relapses, particularly in the face of stressful events.

METHODS

In the current 3-day functional magnetic resonance imaging fear conditioning paradigm, we aimed to create a generalized extinction memory trace in 60 healthy men and women by presenting multiple sizes of 1 conditioned stimulus during extinction training (CS+G; generalized), whereas the other conditioned stimulus was solely presented in its original size (CS+N; nongeneralized). Recall was tested on the third day after pharmacological administration of either the stress hormone cortisol or placebo.

RESULTS

After successful fear acquisition, prolonged activation of the amygdala and insula and deactivation of the ventromedial prefrontal cortex for CS+G compared with CS+N during extinction learning indicated sustained fear to the generalization stimuli. In line with our hypotheses, reduced amygdala activation was observed after extinction generalization on the third day in the contrast CS+G minus CS+N, possibly reflecting an attenuated return of fear. Cortisol administration before recall, however, blocked this effect.

CONCLUSIONS

Taken together, the findings show that extinction generalization was associated with decreased activation of the fear network during recall after prolonged activation of the fear network during extinction learning. However, the generalization of the extinction memory did not counteract the detrimental effects of stress hormones on recall. Thus, stimulus-based extinction generalization may not be sufficient to reduce relapses after stressful experiences.

Positive affective states can play the role of context to renew extinguished instrumental behavior in rats

In one experiment with rats, we examined whether positive affective states can serve as contexts in a between-subjects ABA renewal design using appetitive instrumental conditioning. Two groups of rats received training to press a lever for food where each acquisition session was preceded by administration of a tickling procedure (Context A) known to induce positive affective states. Then, lever pressing underwent extinction where rats received a pure handling treatment (Context B) before each session. During a final test session, we found stronger responding when the session was preceded by tickling (Group ABA) compared to handling (Group ABB), indicating an ABA renewal effect. Furthermore, test performance in Group ABB was not different from that in a third group where handling preceded acquisition sessions, and tickling extinction and test sessions (Group BAA), showing that tickling did not elevate instrumental responding during the test if it had been unrelated to initial acquisition. We discuss implications of our results for understanding the role of positive affective states in relapse of problem behavior.

The Empirical Status of Cue Exposure and Response Prevention Treatment for Binge Eating: A Systematic Review

Approximately 50% of individuals fail to obtain treatment benefits when undergoing cognitive-behavioral therapy (CBT) for binge-eating behaviors, making it necessary to evaluate additional approaches. Cue exposure and response prevention (CERP) is one such approach, although its effectiveness across studies has been inconsistent. This may be due to inconsistent implementation of theoretically based CERP strategies. This possibility has not yet been systematically investigated. To address this gap, this review investigated which CERP strategies have been incorporated into treatment protocols for binge eating, and if the use of certain strategies improves treatment effectiveness. Relevant studies were identified through reference lists, grey literature, and searches of electronic databases using multiple search terms related to CERP and binge eating, which resulted in 18 eligible studies. Most studies were underpowered, many were of low methodological quality, and none of the included studies utilized all of the strategies that have been recommended to optimize CERP. Despite these weaknesses, CERP appeared to reduce the frequency of binge eating in the short and long term. This review underscores the need for higher quality research that utilizes larger samples and uniform outcome measures that are more strongly grounded in theory. Such research would help improve treatment outcomes for binge eating.

Renewal of goal direction with a context change after habit learning

An instrumental action can be goal-directed after a moderate amount of practice and then convert to habit after more extensive practice. Recent evidence suggests, however, that habits can return to action status after different environmental manipulations. The present experiments therefore asked whether habit learning interferes with goal direction in a context-dependent manner like other types of retroactive interference (e.g., extinction, punishment, counterconditioning). In Experiment 1, rats were given a moderate amount of instrumental training to form an action in one context (Context A) and then more extended training of the same response to form a habit in another context (Context B). We then performed reinforcer devaluation with taste aversion conditioning in both contexts, and tested the response in both contexts. The response remained habitual in Context B, but was goal-directed in Context A, indicating renewal of goal direction after habit learning. Experiment 2 expanded on Experiment 1 by testing the response in a third context (Context C). It found that the habitual response also renewed as action in this context. Together, the results establish a parallel between habit and extinction learning: Conversion to habit does not destroy action knowledge, but interferes with it in a context-specific way. They are also consistent with other results suggesting that habit is specific to the context in which it is learned, whereas goal-direction can transfer between contexts. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Resurgence and repeated within-session progressive-interval thinning of alternative reinforcement

Resurgence of a previously suppressed target behavior is common when reinforcement for a more recently reinforced alternative behavior is thinned. To better characterize such resurgence, these experiments examined repeated within-session alternative reinforcement thinning using a progressive-interval (PI) schedule with rats. In Experiment 1, a transition from a high rate of alternative reinforcement to a within-session PI schedule generated robust resurgence, but subsequent complete removal of alternative reinforcement produced no additional resurgence. Experiment 2 replicated these findings and showed similar effects with a fixed-interval (FI) schedule arranging similarly reduced session-wide rates of alternative reinforcement. Thus, the lack of additional resurgence following repeated exposure to the PI schedule was likely due to the low overall obtained rate of alternative reinforcement provided by the PI schedule, rather than to exposure to within-session reinforcement thinning per se. In both experiments, target responding increased at some point in the session during schedule thinning and continued across the rest of the session. Rats exposed to a PI schedule showed resurgence later in the session and after more cumulative alternative reinforcers than those exposed to an FI schedule. The results suggest the potential importance of further exploring how timing and change-detection mechanisms might be involved in resurgence.

Challenges and Opportunities for Grounding Cognition

According to the grounded perspective, cognition emerges from the interaction of classic cognitive processes with the modalities, the body, and the environment. Rather than being an autonomous impenetrable module, cognition incorporates these other domains intrinsically into its operation. The Situated Action Cycle offers one way of understanding how the modalities, the body, and the environment become integrated to ground cognition. Seven challenges and opportunities are raised for this perspective: (1) How does cognition emerge from the Situated Action Cycle and in turn support it? (2) How can we move beyond simply equating embodiment with action, additionally establishing how embodiment arises in the autonomic, neuroendocrine, immune, cardiovascular, respiratory, digestive, and integumentary systems? (3) How can we better understand the mechanisms underlying multimodal simulation, its functions across the Situated Action Cycle, and its integration with other representational systems? (4) How can we develop and assess theoretical accounts of symbolic processing from the grounded perspective (perhaps using the construct of simulators)? (5) How can we move beyond the simplistic distinction between concrete and abstract concepts, instead addressing how concepts about the external and internal worlds pattern to support the Situated Action Cycle? (6) How do individual differences emerge from different populations of situational memories as the Situated Action Cycle manifests itself differently across individuals? (7) How can constructs from grounded cognition provide insight into the replication and generalization crises, perhaps from a quantum perspective on mechanisms (as exemplified by simulators).

A randomized controlled trial protocol for engaging distress tolerance and working memory to aid smoking cessation in low socioeconomic status (SES) adults

Low income and low educational attainment are among the strongest predictors of both smoking prevalence and lapse (i.e., return) to smoking after cessation attempts. Treatment refinement is limited by inadequate knowledge of the specific lapse- or relapse-relevant vulnerabilities characteristic of populations that should be the target of treatment. In the context of a randomized clinical trial design, we describe an experimental medicine approach for evaluating the role of 2 specific lapse-relevant targets relative to the higher stress characteristic of low-socioeconomic contexts: low distress tolerance and low working memory capacity. Furthermore, we use an innovative approach for understanding risk of smoking lapse in smokers undergoing a quit attempt to examine candidate mechanistic targets assessed not only during nicotine use, but also during the conditions smokers will face upon a cessation attempt-during stressful nicotine-deprivation windows. This study is designed to show the incremental value of assessments during deprivation windows, in part because of the way in which specific vulnerabilities are modified by, and interact with, the heightened stress and withdrawal symptoms inherent to nicotine-deprivation states. Specifically, the study is designed to evaluate whether a novel mindfulness intervention (mindfulness combined with interoceptive exposure) can improve upon existing mindfulness interventions and extend therapeutic gains to the modification of mechanistic targets assessed in high-stress or negative affectivity contexts. The overall goal is to validate mechanistic targets and associated interventions for the purpose of expanding treatment options for at-risk smokers. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The Mesolimbic Dopamine Activity Signatures of Relapse to Alcohol-Seeking

The mesolimbic dopamine system comprises distinct compartments supporting different functions in learning and motivation. Less well understood is how complex addiction-related behaviors emerge from activity patterns across these compartments. Here we show how different forms of relapse to alcohol-seeking in male rats are assembled from activity across the VTA and the nucleus accumbens. First, we used chemogenetic approaches to show a causal role for VTA TH neurons in two forms of relapse to alcohol-seeking: renewal (context-induced reinstatement) and reacquisition. Then, using gCaMP fiber photometry of VTA TH neurons, we identified medial and lateral VTA TH neuron activity profiles during self-administration, renewal, and reacquisition. Next, we used optogenetic inhibition of VTA TH neurons to show distinct causal roles for VTA subregions in distinct forms of relapse. We then used dLight fiber photometry to measure dopamine binding across the ventral striatum (medial accumbens shell, accumbens core, lateral accumbens shell) and showed complex and heterogeneous profiles of dopamine binding during self-administration and relapse. Finally, we used representational similarity analysis to identify mesolimbic dopamine signatures of self-administration, extinction, and relapse. Our results show that signatures of relapse can be identified from heterogeneous activity profiles across the mesolimbic dopamine system and that these signatures are unique for different forms of relapse.SIGNIFICANCE STATEMENT It is axiomatic that the actions of dopamine are critical to drug addiction. Yet how relapse to drug-seeking is assembled from activity across the mesolimbic dopamine system is poorly understood. Here we show how relapse to alcohol-seeking relates to activity in specific VTA and accumbens compartments, how these change for different forms of relapse, and how relapse-associated activity relates to activity during self-administration and extinction. We report the mesolimbic dopamine activity signatures for relapse and show that these signatures are unique for different forms of relapse.

Reduced renewal of conditioned suppression following lesions of the dorsal hippocampus in male rats

Extinguished responding will renew when the conditioned stimulus occurs outside the extinction context. Although studies of conditioned freezing have consistently demonstrated a role for the hippocampus in renewal, several studies have demonstrated intact renewal of conditioned suppression despite damage to the hippocampus (Frohardt, Guarraci, & Bouton, 2000; Todd, Jiang, DeAngeli, & Bucci, 2017; Wilson, Brooks, & Bouton, 1995). Because these prior studies have examined renewal when testing occurred in the original conditioning context ("Context A"), the present conditioned suppression experiments examined the role of the hippocampus when testing occurred in a context not associated with prior conditioning ("Context C"). In Experiments 1 and 2, conditioning occurred in Context A, and extinction in Context B. Renewal of conditioned suppression was observed when the extinguished conditioned stimulus (CS) was tested in Context C. However, renewal was attenuated in rats with lesions of the dorsal hippocampus (DH). Summation testing failed to detect conditioned inhibition in the extinction context, suggesting instead that the context acquired negative occasion-setting properties. Attenuated renewal was not due to an inability of DH lesioned rats to discriminate contexts (Experiment 3). These experiments thus demonstrate a role for the DH in renewal of conditioned suppression when testing occurs in a neutral context. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Context and renewal of habits and goal-directed actions after extinction

Instrumental behaviors that are goal-directed actions after moderate amounts of training can become habits after more extended training. Little research has asked how actions and habits are affected by retroactive interference treatments like extinction. The present experiments begin to fill this gap in the literature. In Experiments 1a and 1b, lever pressing in rats was minimally trained (1a) or extensively trained (1b) in one context (Context A), extinguished in a second context (Context B), and then tested in the acquisition context (Context A). Exposure to both contexts was equated and controlled throughout, and the status of the behavior as action or habit was determined by reinforcer devaluation methods (taste aversion conditioning). Results confirmed that action (1a) and habit (1b) renewed with action or habit status, respectively, when they were returned to Context A. Experiments 2a and 2b then similarly tested action and habit after extinction in an ABC renewal paradigm. Here, lever pressing that was trained in Context A and extinguished in Context B renewed as action in Context C regardless of whether it had been an action or habit before extinction. The apparent conversion of habit to action during renewal testing in Context C was consistent with other results suggesting that habits converted to action when the context was changed at the start of extinction. Together, the results suggest that extinction in a second context inhibits instrumental behaviors trained as either actions or habits in a context-specific manner. They also expand on prior findings suggesting that actions transfer across contexts, and that habits do not. A change of context may be sufficient to convert a habit to goal-directed action. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Left Inferior Frontal Gyrus Participates in Mediating the Renewal Effect Irrespective of Context Salience

The renewal effect of extinction demonstrates the context-dependency of extinction learning. It is defined as the recovery of an extinguished response occurring when the contexts of extinction and recall differ. Behavioral studies showed that modulating context relevance can strengthen context-specific responses. In our fMRI study, we investigated to what extent a modulation of context salience can alter renewal levels and provide additional information about the neural basis for renewal. In a within-subjects design, participants completed two sessions of an associative learning task in randomized order. In the salient condition (SAL), a context was presented alone at the start of each trial, before being presented together with the stimulus. The regular condition (REG) contained no context-alone phase. In about one-third of participants (SWITCH), the context salience modulation significantly increased renewal rates in the SAL compared to the REG condition. The other participants showed either renewal (REN) or no renewal (NoREN) in both conditions. The modulation did not significantly affect learning performance during the initial forming of associations or extinction learning. In the SWITCH group, activation in left opercular inferior frontal gyrus (iFG) during the recall phase was associated with a renewal effect, together with activity in the bilateral posterior hippocampus and ventromedial prefrontal cortex (vmPFC). Also during the extinction phase, left opercular iFG activation was higher in groups exhibiting renewal in recall, irrespective of the context salience modulation. Besides confirming the participation of vmPFC in extinction recall, our findings provide novel insights regarding an as yet undetected, potentially important role for renewal-supporting processes in left iFG during extinction learning and recall, which are presumably based on the region's proposed function of evaluating competing response options under conditions of ambiguity.

Sign-tracking behavior is sensitive to outcome devaluation in a devaluation context-dependent manner: implications for analyzing habitual behavior

Motivationally attractive cues can draw in behavior in a phenomenon termed incentive salience. Incentive cue attraction is an important model for animal models of drug seeking and relapse. One question of interest is the extent to which the pursuit of motivationally attractive cues is related to the value of the paired outcome or can become unrelated and habitual. We studied this question using a sign-tracking (ST) paradigm in rats, in which a lever stimulus preceding food reward comes to elicit conditioned lever-interaction behavior. We asked whether reinforcer devaluation by means of conditioned taste aversion, a classic test of habitual behavior, can modify ST to incentive cues, and whether this depends upon the manner in which reinforcer devaluation takes place. In contrast to several recent reports, we conclude that ST is indeed sensitive to reinforcer devaluation. However, this effect depends critically upon the congruence between the context in which taste aversion is learned and the context in which it is tested. When the taste aversion successfully transfers to the testing context, outcome value strongly influences ST behavior, both when the outcome is withheld (in extinction) and when animals can learn from outcome feedback (reacquisition). When taste aversion does not transfer to the testing context, ST remains high. In total, the extent to which ST persists after outcome devaluation is closely related to the extent to which that outcome is truly devalued in the task context. We believe this effect of context on devaluation can reconcile contradictory findings about the flexibility/inflexibility of ST. We discuss this literature and relate our findings to the study of habits generally.

The impacts of acquisition and extinction cues on ABC renewal of voluntary behaviors

In two instrumental conditioning experiments with rats, we examined the impacts of acquisition and extinction cues on ABC renewal of instrumental behavior. Animals were reinforced with food for lever pressing in one context, followed by extinction of the response in a second one. Presentations of a brief tone accompanied extinction in Experiment 1 (extinction cue), and acquisition in Experiment 2 (acquisition cue). A final test in a third context revealed that instrumental responding was decreased in the presence of the extinction cue, whereas it was increased in the presence of the acquisition cue. We discuss theoretical and clinical implications of our results.

Changes in the elimination and resurgence of alcohol-maintained behavior in rats and the effects of naltrexone

Resurgence may be a mechanism of relapse in alcohol use disorder patients upon discharge from treatment as part of an abuse-treatment-relapse cycle. Adjunctive pharmacotherapies may be a means to facilitate behavioral treatments and block resurgence. Experiments were conducted using a model of alcohol self-administration to assess the repeatability of the elimination and resurgence of alcohol-maintained behavior and the effects of naltrexone. Experiments had three phases. In Phase 1, behavior was maintained by oral alcohol under a fixed-ratio schedule. In Phase 2, behavior was extinguished via condensed milk delivery under a differential-reinforcement-of-other-behavior (DRO) schedule. In Phase 3, the DRO schedule was eliminated. In Experiment 1, this 3-phase cycle was replicated 4 times. Across replications, response rates and dose of alcohol consumed did not differ in Phase 1, alcohol-maintained behavior was eliminated more rapidly in Phase 2, and the resurgence effect was generally stable in Phase 3. In Experiment 2, naltrexone was administered in Phase 2, Phase 3, or both Phases 2 and 3, to separate groups of rats. Naltrexone facilitated the elimination of alcohol-maintained behavior in Phase 2 and, the resurgence of alcohol-maintained behavior was reduced only for those rats that received naltrexone in both phases. Together, these experiments demonstrate that the resurgence of alcohol-maintained behavior is replicable within-subjects and, further, resurgence of alcohol-maintained behavior may be a useful model to evaluate pharmacological interventions to facilitate behavioral treatments and reduce the likelihood of relapse. Results with naltrexone support the use of medication-assisted therapy approaches to reduce relapse risk in patients. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Complementary Roles for Ventral Pallidum Cell Types and Their Projections in Relapse

The ventral pallidum (VP) is a key node in the neural circuits controlling relapse to drug seeking. How this role relates to different VP cell types and their projections is poorly understood. Using male rats, we show how different forms of relapse to alcohol-seeking are assembled from VP cell types and their projections to lateral hypothalamus (LH) and ventral tegmental area (VTA). Using RNAScope in situ hybridization to characterize activity of different VP cell types during relapse to alcohol-seeking provoked by renewal (context-induced reinstatement), we found that VP Gad1 and parvalbumin (PV), but not vGlut2, neurons show relapse-associated changes in c-Fos expression. Next, we used retrograde tracing, chemogenetic, and electrophysiological approaches to study the roles of VPGad1 and VPPV neurons in relapse. We show that VPGad1 neurons contribute to contextual control over relapse (renewal), but not to relapse during reacquisition, via projections to LH, where they converge with ventral striatal inputs onto LHGad1 neurons. This convergence of striatopallidal inputs at the level of individual LHGad1 neurons may be critical to balancing propensity for relapse versus abstinence. In contrast, VPPV neurons contribute to relapse during both renewal and reacquisition via projections to VTA. These findings identify a double dissociation in the roles for different VP cell types and their projections in relapse. VPGad1 neurons control relapse during renewal via projections to LH. VPPV neurons control relapse during both renewal and reacquisition via projections to VTA. Targeting these different pathways may provide tailored interventions for different forms of relapse.SIGNIFICANCE STATEMENT Relapse to drug or reward seeking after a period of extinction or abstinence remains a key impediment to successful treatment. The ventral pallidum, located in the ventral basal ganglia, has long been recognized as an obligatory node in a 'final common pathway' for relapse. Yet how this role relates to the considerable VP cellular and circuit heterogeneity is not well understood. We studied the cellular and circuit architecture for VP in relapse control. We show that different forms of relapse have complementary VP cellular and circuit architectures, raising the possibility that targeting these different neural architectures may provide tailored interventions for different forms of relapse.

A review of investigations of operant renewal with human participants: Implications for theory and practice

Operant renewal is the recurrence of a previously eliminated target behavior as a function of changing stimulus contexts. Renewal as a model of treatment relapse in humans suggests that a change in stimulus conditions or context is sufficient to produce relapse of a previously eliminated maladaptive behavior. The extent to which general findings from operant renewal studies involving nonhuman animal subjects are supported by relapse studies involving human participants is unknown. We conducted a systematic review of studies demonstrating or mitigating operant renewal in human participants in peer-reviewed studies found in PsycINFO, ERIC, PubMed, and Scopus between 1980 and 2019. We identified 12 studies involving 61 participants and 93 cases of operant renewal. We coded descriptive data on participant and study characteristics and calculated summary statistics. Results indicated that the renewal effect was a robust phenomenon, supported by demonstrations in both clinical and human-laboratory studies, and across a variety of variables and experimental preparations. However, there were relatively few studies involving human participants that attempted to reduce or eliminate renewal of clinically meaningful behavior. We discuss variables relevant for studying renewal in socially meaningful contexts, practical limitations of observing the renewal effect in real-world settings, implications for theoretical models of renewal, and identify barriers to methodology unique to human participants. We provide directions for future research related to implementing and translating nonhuman animal studies of renewal to applied settings.

Vagus nerve stimulation during extinction learning reduces conditioned place preference and context-induced reinstatement of cocaine seeking

BACKGROUND

Drug use causes the formation of strong cue/reward associations which persist long after cessation of drug-taking and contribute to the long-term risk of relapse. Extinguishing these associations may reduce cue-induced craving and relapse. Previously, we found that pairing vagus nerve stimulation (VNS) with extinction of cocaine self-administration reduces cue-induced reinstatement; however, it remains unclear whether this was primarily caused by extinguishing the context, the instrumental response, or both.

OBJECTIVE

Hypothesis: We hypothesized that VNS can facilitate the extinction of both contextual cues and instrumental responding.

METHODS

Extinction of context was first tested using Pavlovian conditioned place preference (CPP). Next, the impact of VNS on the extinction of instrumental responding was assessed under ABA and AAA context conditions. In each extinction context separate groups of rats were either provided the opportunity to perform the instrumental response, or the levers were retracted for the duration of extinction training. Reinstatement was induced by reintroduction of the conditioned stimuli and/or the drug-paired context. Data were analyzed using one-way or two-way repeated measures ANOVAs.

RESULTS

VNS during extinction reduced reinstatement of CPP. VNS also reduced cue- and context-induced reinstatement of the instrumental response under both AAA and ABA conditions. The subjects' ability to engage with the lever during extinction was crucial for this effect. P values < 0.05 were considered significant.

CONCLUSIONS

Craving occurs in response to a range of conditioned stimuli and contexts; VNS may improve outcomes of behavioral therapy by facilitating extinction of both an instrumental response and/or contextual cues.

Time-dependent effects of psychosocial stress on the contextualization of neutral memories

Memories about stressful experiences need to be both specific and generalizable to adequately guide future behavior. Memory strength is influenced by emotional significance, and contextualization (i.e., encoding experiences with their contextual details) enables selective context-dependent retrieval and protects against overgeneralization. The current randomized-controlled study investigated how the early and late phase of the endogenous stress response affects the contextualization of neutral and negative information. One hundred healthy male participants were randomly divided into three experimental groups that performed encoding either 1) without stress (control), 2) immediately after acute stress (early) or 3) two hours after acute stress (late). Stress was induced via the Trier Social Stress Test and salivary alpha-amylase and cortisol levels were measured throughout the experiment. In the Memory Contextualization Task, neutral and angry faces (items) were depicted against unique context pictures during encoding. During testing 24 h later, context-dependent recognition memory of the items was assessed by presenting these in either congruent or incongruent contexts (relative to encoding). Multilevel analyses revealed that neutral information was more contextualized when encoding took place two hours after psychosocial stress, than immediately after the stressor. Results suggest that the late effects in the unique, time-dependent sequence of a healthy endogenous stress response, could complement reduced contextualization immediately after stress. The contextualization of negative information was not influenced by psychosocial stress, as opposed to earlier reported effects of exogenous hydrocortisone administration. An imbalance between the early and late effects of the endogenous stress response could increase vulnerability for stress-related psychopathology.

Anti-relapse neurons in the infralimbic cortex of rats drive relapse-suppression by drug omission cues

Drug addiction is a chronic relapsing disorder of compulsive drug use. Studies of the neurobehavioral factors that promote drug relapse have yet to produce an effective treatment. Here we take a different approach and examine the factors that suppress-rather than promote-relapse. Adapting Pavlovian procedures to suppress operant drug response, we determined the anti-relapse action of environmental cues that signal drug omission (unavailability) in rats. Under laboratory conditions linked to compulsive drug use and heightened relapse risk, drug omission cues suppressed three major modes of relapse-promotion (drug-predictive cues, stress, and drug exposure) for cocaine and alcohol. This relapse-suppression is, in part, driven by omission cue-reactive neurons, which constitute small subsets of glutamatergic and GABAergic cells, in the infralimbic cortex. Future studies of such neural activity-based cellular units (neuronal ensembles/memory engram cells) for relapse-suppression can be used to identify alternate targets for addiction medicine through functional characterization of anti-relapse mechanisms.

The reoccurrence of voluntary behavior in humans is reduced by retrieval cues from extinction

Changes in the temporal as well as the physical context produces the reappearance of extinguished behaviors. Furthermore, combining both kinds of contextual stimuli often causes greater levels of recovery. The current experiment explored the impact of extinction reminders on spontaneous recovery, renewal, and a combination of both effects using an instrumental learning task with humans. All participants learned to shoot at enemies in a videogame. Then, throughout extinction, the instrumental response was eliminated. We found a return of the extinguished behavior by introducing a retention interval of 48 h, by changing the physical background and by testing participants in a spatiotemporal context different from the extinction context. However, we also found that the presentation of a stimulus directly associated with extinction attenuates all three forms of operant reoccurrence. These results are consistent with the perspective that emphasizes that context plays a key role in response-recovery phenomena. Moreover, our findings may be promissory for therapeutic strategies involving relapse treatment.

Resurgence as Choice: Implications for promoting durable behavior change

Resurgence is an increase in a previously suppressed behavior resulting from a worsening in reinforcement conditions for current behavior. Resurgence is often observed following successful treatment of problem behavior with differential reinforcement when reinforcement for an alternative behavior is subsequently omitted or reduced. The efficacy of differential reinforcement has long been conceptualized in terms of quantitative models of choice between concurrent operants (i.e., the matching law). Here, we provide an overview of a novel quantitative model of resurgence called Resurgence as Choice (RaC), which suggests that resurgence results from these same basic choice processes. We review the failures of the only other quantitative model of resurgence (i.e., Behavioral Momentum Theory) and discuss its shortcomings with respect to the limited range of circumstances about which it makes predictions in applied settings. Finally, we describe how RaC overcomes these shortcomings and discuss implications of the model for promoting durable behavior change.

Renewal of extinguished behavior in pigeons (Columba livia) does not require memory consolidation of acquisition or extinction in a free-operant appetitive conditioning paradigm

Extinction learning is a fundamental capacity for adaptive and flexible behavior. As extinguished conditioned responding is prone to relapse under certain conditions, the necessity of memory consolidation for recovery phenomena to occur has been highlighted recently. Several studies have demonstrated that both acquisition and extinction training need to be properly consolidated for a relapse of the original acquired memory trace to occur. Does this imply that extinguished responses cannot relapse before memory consolidation? To answer this question, we investigated the renewal effect subsequent to an immediate or a delayed (24 h) extinction in a discriminative operant conditioning paradigm. In three different experiments, we could show (1) that acquisition learning does not need to be long-term consolidated for the occurrence of renewal, (2) that the offset of extinction training is a reliable marker for extinction recall in a free-operant extinction learning paradigm where organisms undergo consecutive acquisition training, extinction training as well as testing of conditioned responding and (3), that immediate and long-term consolidated renewal do not demonstrate any qualitative difference in terms of the behavioral output. Our results indicate on the behavioral level that the inhibitory nature of extinction is already present in free-operant learning paradigms and that it does not seem to be affected by the absence of long-term memory consolidation.

Removing but not adding elements of a context affects generalization of instrumental responses

Three experiments with rats investigated whether adding or removing elements of a context affects generalization of instrumental behavior. Each of the experiments used a free operant procedure. In Experiments 1 and 2, rats were trained to press a lever for food in a distinctive context. Then, transfer of lever pressing was tested in a context created either by adding an element to the context of initial acquisition or by removing one of the acquisition context's elements. In Experiment 3, a similar generalization test was conducted after rats received acquisition and extinction within the same context. For Experiments 1 and 2, we observed that removing elements from the acquisition context disrupted acquisition performance, whereas the addition of elements to the context did not. Experiment 3 revealed that removing elements from but not adding elements to the original context improved extinction performance. Our results are consistent with an elemental view of context representation.

Retrieval practice after multiple context changes, but not long retention intervals, reduces the impact of a final context change on instrumental behavior

Recent evidence from this laboratory suggests that a context switch after operant learning consistently results in a decrement in responding. One way to reduce this decrement is to train the response in multiple contexts. One interpretation of this result, rooted in stimulus sampling theory, is that conditioning of a greater number of common stimulus elements arising from more contexts causes better generalization to new contexts. An alternative explanation is that each change of context causes more effortful retrieval, and practice involving effortful retrieval results in learning that is better able to transfer to new situations. The current experiments were designed to differentiate between these two explanations for the first time in an animal learning and memory task. Experiment 1 demonstrated that the detrimental impact of a context change on an instrumental nose-poking response can be reduced by training the response in multiple contexts. Experiment 2 then found that a training procedure which inserted extended retention intervals between successive training sessions did not reduce the detrimental impact of a final context change. This occurred even though the inserted retention intervals had a detrimental impact on responding (and, thus, presumably retrieval) similar to the effect that context switches had in Experiment 1. Together, the results suggest that effortful retrieval practice may not be sufficient to reduce the negative impact of a context change on instrumental behavior. A common elements explanation which supposes that physical and temporal contextual cues do not overlap may account for the findings more readily.

The immediate extinction deficit occurs in a nonemotional learning paradigm

The immediate extinction deficit describes a higher return of fear when extinction takes place immediately after fear acquisition compared to a delayed extinction design. One explanation for this phenomenon encompasses the remaining emotional arousal evoked by fear acquisition to be still present during immediate, but not delayed extinction. In the present study, the predictive learning task, a learning task not involving arousal or stress, was used testing the hypothesis that no immediate extinction deficit should occur in this neutral task. Twenty-six participants underwent an immediate extinction procedure and were tested in a recall session 24 h later. For the delayed extinction group (n = 26), acquisition, extinction, and recall were realized 24 h apart from each other. Recall performance of a third group (n = 26) was tested 48 h after the immediate extinction procedure. The immediate extinction deficit was indeed observed for a stimulus not subject to a contextual change from acquisition to extinction, but not for other stimuli involving contextual changes or no extinction control stimuli. Even in a neutral learning task and without emotional arousal, the immediate extinction deficit could be detected but was restricted to the specific contextual embedding of stimuli. Thus, contextual processing appears to differentially modulate the emergence of the immediate extinction deficit.

Context-induced relapse after extinction versus punishment: similarities and differences

Results from clinical studies suggest that drug relapse and craving are often provoked by exposure to drug-associated contexts. Since 2002, this phenomenon has been modeled in laboratory animals using the ABA renewal model. In the classical version of this model, rats with a history of drug self-administration in one context (A) undergo extinction in a different context (B) and reinstate (or relapse to) drug seeking after exposure to the original drug-associated context (A). In a more recent version of the model introduced in 2013, the experimental conditions in context A are identical to those used in the classical model, but drug-reinforced responding in context B is suppressed by probabilistic punishment. The punishment-based ABA renewal model is proposed to resemble abstinence in humans, which is often initiated by the desire to avoid the negative consequences of drug use. The goal of our review is to discuss similarities and differences in mechanisms that play a role in suppression of drug seeking in context B and context-induced relapse to drug seeking in context A in the two models. We first describe psychological mechanisms that mediate extinction and punishment of drug-reinforced responding in context B. We then summarize recent findings on brain mechanisms of context-induced relapse of drug seeking after extinction, or punishment-imposed abstinence. These findings demonstrate both similarities and differences in brain mechanisms underlying relapse in the two variations of the ABA renewal model. We conclude by briefly discussing clinical implications of the preclinical studies.