Renewal of extinguished operant behavior following changes in social context

Renewal of cocaine seeking using social and nonsocial contextual stimuli

RATIONALE

Various nonsocial cues have been used as stimuli to examine the contextual control of drug seeking behavior, but little is known about the role of social stimuli.

OBJECTIVES

This study determined if renewal of cocaine seeking is differentially controlled using a context consisting of either a social peer and/or house light illumination.

METHODS

In Experiment 1, male and female rats trained to self-administer cocaine in the presence of a same-sex social peer and house light illumination (context A). Following self-administration, rats were randomly assigned to either an AAA (control) or ABA (renewal) group for extinction. For AAA rats, extinction consisted of the same context A as self-administration; for ABA rats, extinction occurred without the peer or house light (context B). Following extinction, renewal of cocaine seeking occurred by testing the peer alone, house light alone, and the peer + house light combination. Experiment 2 was conducted to ensure that the house light alone was sufficiently salient to produce renewal.

RESULTS

Both experiments showed that rats acquired cocaine self-administration and extinguished lever pressing. In Experiment 1, the ABA group renewed cocaine seeking to the peer and peer + house light, but not to the house light alone. In Experiment 2, ABA rats renewed cocaine seeking to the house light alone, indicating it was sufficiently salient to produce renewal. The AAA group did not show renewal in either experiment.

CONCLUSION

Social peers serve as powerful stimuli that can overshadow nonsocial visual stimuli in the renewal of cocaine seeking.

Relapse and its mitigation: Toward behavioral inoculation

Relapse following the successful treatment of problem behavior can increase the likelihood of injury and the need for more intensive care. Current research offers some predictions of how treatment procedures may contribute to relapse, and conversely, how the risk of relapse can be mitigated. This review describes relapse-mitigation procedures with varying levels of support, the quantitative models that have influenced the research on relapse mitigation, different experimental methods for measuring relapse mitigation, and directions for future research. We propose that by viewing the implementation of relapse-mitigation procedures as a means of producing behavioral inoculation, clinicians are placed in the proactive and intentional role of exposing their client's behavior to an array of reinforcement and stimulus conditions during treatment with the goal of decreasing the detrimental impact of future treatment challenges.

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.

Peer-induced cocaine seeking in rats: Comparison to nonsocial stimuli and role of paraventricular hypothalamic oxytocin neurons

The purpose of this study was to determine if social vs nonsocial cues (peer vs light/tone) can serve as discriminative stimuli to reinstate cocaine seeking. In addition, to assess a potential mechanism, an oxytocin (OT) promoter-linked hM3Dq DREADD was infused into the paraventricular nucleus of the hypothalamus to determine whether peer-induced cocaine seeking is decreased by activation of OT neurons. Male rats underwent twice-daily self-administration sessions, once with cocaine in the presence of one peer (S+) and once with saline in the presence of a different peer (S-). Another experiment used similar procedures, except the discriminative stimuli were nonsocial (constant vs flashing light/tone), with one stimulus paired with cocaine (S+) and the other paired with saline (S-). A third experiment injected male and female rats with OTp-hM3Dq DREADD or control virus into PVN and tested them for peer-induced reinstatement of cocaine seeking following clozapine (0.1 mg/kg). Although acquisition of cocaine self-administration was similar in rats trained with either peer or light/tone discriminative stimuli, the latency to first response was reduced by the peer S+, but not by the light/tone S+. In addition, the effect of the conditioned stimulus was overshadowed by the peer S+ but not by the light/tone S+. Clozapine blocked the effect of the peer S+ in rats receiving the OTp-hM3Dq DREADD virus, but not in rats receiving the control virus. These results demonstrate that a social peer can serve as potent trigger for drug seeking and that OT in PVN modulates peer-induced reinstatement of cocaine seeking.

The extinction burst: Impact of reinforcement time and level of analysis on measured prevalence

Despite widespread belief in the extinction burst as a common occurrence, relatively little empirical work has focused directly on the phenomenon. In order to provide additional data on the topic, we report reanalyses of published extinction-control groups from our laboratory following training with a variety of schedules and reinforcers. In addition, two prospective experiments were conducted in which rats responded for food on FR 5 or FR 1 schedules prior to a within-session transition to extinction. The results of these reanalyses and experiments suggest that the obtained prevalence of the extinction burst was considerably greater when response rates in the first minute of the transition to extinction were considered as compared to when session-wide response rates were considered. In addition, when reinforcement time was included in baseline response-rate calculations, the obtained prevalence of the extinction burst was higher than when reinforcement time was omitted. These findings highlight the importance of measurement and definitional issues in the obtained prevalence of the extinction burst. Further, a closer alignment of such issues across basic and applied research would be desirable in terms of the development of future theories describing the processes giving rise to the extinction burst.

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.

Further evaluation of a nonsequential approach to studying operant renewal

Basic-laboratory assessments of renewal may inform clinical efforts to maintain reduction of severe destructive behavior when clients transition between contexts. The contextual changes arranged during standard renewal procedures, however, do not necessarily align with those that clients experience during outpatient therapy. More specifically, clients transition between clinical (associated with extinction for target behavior) and home/community (associated with reinforcement for target behavior) contexts during outpatient treatment. Standard renewal assessments do not incorporate these contextual alternations during treatment. The present experiment aimed to directly compare renewal of rats' lever pressing following a standard ("sequential") ABA renewal procedure (i.e., baseline in Context A, extinction in Context B, renewal test in Context A) and a "nonsequential" renewal assessment wherein treatment consisted of daily alternation between Context A (associated with reinforcement for lever pressing) and Context B (associated with extinction). Lever pressing renewed to a greater extent for rats in the Nonsequential group than for rats in the Sequential group, suggesting the contextual changes that clients experience during outpatient treatment for severe destructive behavior may be a variable that is important to consider in translational research on renewal. Potential implications of these findings for basic and clinical research on renewal are discussed.

Translational approach to understanding momentary factors associated with alcohol consumption

Multiple interindividual and intra-individual factors underlie variability in drinking motives, challenging clinical translatability of animal research and limiting treatment success of substance use-related problems. Intra-individual variability refers to time-dependent continuous and discrete changes within the individual and in substance use research is studied as momentary variation in the internal states (craving, stressed, anxious, impulsive and tired) and response to external triggers (stressors, drug-associated environmental cues and social encounters). These momentary stimuli have a direct impact on behavioural decisions and may be triggers and predictors of substance consumption. They also present potential targets for real-time behavioural and pharmacological interventions. In this review, we provide an overview of the studies demonstrating different momentary risk factors associated with increased probability of alcohol drinking in humans and changes in alcohol seeking and consumption in animals. The review also provides an overview of pharmacological interventions related to every individual risk factor.

Renewal of fear and avoidance in humans to escalating threat: Implications for translational research on anxiety disorders

Exposure-based treatment for threat avoidance in anxiety disorders often results in fear renewal. However, little is known about renewal of avoidance. This multimodal laboratory-based treatment study used an ABA renewal design and an approach-avoidance (AP-AV) task to examine renewal of fear/threat and avoidance in twenty adults. In Context A, 9 visual cues paired with increases in probabilistic money loss (escalating threats) produced increases in ratings of feeling threatened and loss expectancies and skin-conductance responses (SCR). During the AP-AV task, a monetary reinforcer was available concurrently with threats. Approach produced the reinforcer or probabilistic loss, while avoidance prevented loss and forfeited reinforcement. Escalating threat produced increasing avoidance and ratings. In Context B with Pavlovian extinction, threats signaled no money loss and SCR declined. During the AP-AV task, avoidance and ratings also declined. In a return to Context A with Pavlovian threat extinction in effect during the AP-AV task, renewal was observed. Escalating threat was associated with increasing ratings and avoidance in most participants. SCR did not show renewal. These are the first translational findings to highlight renewal of avoidance in humans. Further research should identify individual difference variables and altered neural mechanisms that may confer increased risk of avoidance renewal.