Effects of extended extinction and multiple extinction contexts on ABA renewal

Preclinical behavioral and pharmacological treatments for enhancing fear extinction in adolescence

Adolescence is a window of vulnerability for the development of anxiety disorders but also a window of opportunity for treatments to minimize the long-term impact of such disorders. Current first-line treatments, primarily exposure-based cognitive-behavioral therapy (CBT), have limited long-term efficacy in adolescents. The urgent need for more effective interventions is underscored by the frequent reports of extinction impairments in adolescents as well as the rising anxiety rates in youth, particularly post-COVID-19. Preclinical research on the extinction of learned fear in adolescents may contribute to developing better treatment approaches to anxiety in this age group. Unfortunately, this is still a largely under-explored area. However, both pharmacological and behavioral augmentation strategies can be used to enhance extinction learning and consolidation. Here we describe work exploring such adjuncts, focusing on pre-clinical work with rodents. Much of the research to date shows striking developmental differences in response to various pharmacological treatments, with only a few shown to be effective in adolescents. Further, recent experience of stress reduces the efficacy of these treatments in adolescence. This review highlights the necessity for tailored strategies, especially when it comes to pharmacological adjuncts, that address developmental differences in drug responses as well as the impact of stressful experiences on treatment efficacy.

Exploration of stress reactivity and fear conditioning on intrusive memory frequency in a conditioned-intrusion paradigm

BACKGROUND AND OBJECTIVES

The conditioned-intrusion paradigm was designed to provide insight into the relationship between fear conditioning and intrusive memory formation, which is relevant to understanding posttraumatic stress disorder symptoms and treatment. However, boundary conditions of this new paradigm have not been explored and it is currently not known whether findings from this work are valid in a clinical context.

METHODS

In the current study, we explored the relationship between stress reactivity to trauma film clips, usual exposure to violent media, renewal of fear conditioning using skin conductance as well as subjective ratings, and the effect of shock versus film clip during conditioning on the frequency of intrusive memories. An adapted fear conditioning paradigm using trauma clips as unconditional stimuli was used, and participants subsequently reported intrusive memories of the trauma clips.

RESULTS

Skin conductance responses to conditioned stimuli paired with shocks and film clips were significantly higher than conditioned stimuli paired with film clips alone. Subjective stress reactivity, previous exposure to violent media, and film valence rating were associated with the frequency of intrusive memories. No aspects of fear conditioning were associated with intrusive memories, and factor analysis suggested the fear conditioning and stress related to film clip viewing were mostly separate constructs. Similarly, content and triggers of intrusive memories were usually film-clip related rather than conditional stimulus related.

LIMITATIONS

We did not observe strong conditioning effects of the unconditional stimuli to conditional stimuli, which were shapes rather than high frequency stimuli such as faces.

CONCLUSIONS

These findings provide potential boundary conditions for this paradigm and suggest multiple ways in which the validity of the paradigm can be tested in the future.

Extinction in multiple contexts reduces the return of extinguished responses: A multilevel meta-analysis

Extinguished responses have been shown to reappear under several circumstances, and this reappearance is considered to model behaviors such as relapse after exposure therapy. Conducting extinction in multiple contexts has been explored as a technique to decrease the recovery of extinguished responses. The present meta-analysis aimed to examine whether extinction in multiple contexts can consistently reduce the recovery of extinguished responses. After searching in several databases, experiments were included in the analysis if they presented extinction in multiple contexts, an experimental design, and an adequate statistical report. Cohen's d was obtained for each critical comparison and weighted to obtain the sample's average weighted effect size. Analyses were then performed using a multilevel meta-analytic approach. Twenty-five studies were included, with a total sample of 37 experiments or critical comparisons. The analyses showed a large effect size for the sample, moderated by the length of conditioned stimulus exposure, type of experimental subject, and type of recovery. The robust effect of extinction in multiple contexts on relapse should encourage clinicians to consider extinction in multiple contexts as a useful technique in therapy and research.

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.

Renewal in human fear conditioning: A systematic review and meta-analysis

Renewal is a 'return of fear' manipulation in human fear conditioning to investigate learning processes underlying anxiety and trauma. Even though renewal paradigms are widely used, no study has compared the strength of different renewal paradigms. We conduct a systematic review (N = 80) and meta-analysis (N = 23) of human fear conditioning studies assessing renewal. Our analysis shows that the classic ABA design is the most effective paradigm, compared to ABC and ABBA designs. We present evidence that conducting extinction in multiple contexts and increasing the similarity between acquisition and extinction contexts reduce renewal. Furthermore, we show that additional cues can be used as safety and 'protection from extinction' cues. The review shows that alcohol weakens the extinction process and that older adults appear less sensitive to context changes and thus show less renewal. The large variability in approaches to study renewal in humans suggests that standardisation of fear conditioning procedures across laboratories would be of great benefit to the field.

Efficacy of D-cycloserine augmented brief intensive cognitive-behavioural therapy for paediatric obsessive-compulsive disorder: A randomised clinical trial

OBJECTIVE

To examine the efficacy of weight-adjusted D-cycloserine (DCS) (35 or 70 mg) relative to placebo augmentation of intensive exposure therapy for youth with obsessive-compulsive disorder (OCD) in a double-blind, randomised controlled trial, and examine whether antidepressant medication or patient age moderated outcomes.

METHODS

Youth (n = 100, 7-17 years) with OCD were randomised in a 1:1 ratio to either DCS + exposure (n = 49) or placebo + exposure (n = 51). Assessments occurred posttreatment, 1 month later, and at 3 and 6 months. Pills were ingested immediately before sessions.

RESULTS

Significant improvements on all outcomes were observed at posttreatment, and to 6-month follow-up. Treatment arms did not differ across time, with no significant time-by-medication interactions on symptom severity (T1 to T2 estimate: 9.3, 95% confidence interval [CI]: -11.2 to -7.4, and estimate -10.7, 95% CI: -12.6 to -8.7), diagnostic severity (T1 to T2 estimate: -2.0, 95% CI: -2.4 to -1.5 and estimate -2.5, 95% CI: -3.0 to -2.0) or global functioning (T1 to T2 estimate: 13.8, 95% CI: 10.6 to 17.0, and estimate 16.6, 95% CI: 13.2 to 19.9). Neither antidepressants at baseline nor age moderated primary outcomes. There were significantly fewer responders/remitters at 1- and 6-month follow-up among youth in the DCS condition stabilised on SSRIs, relative to youth not taking SSRIs.

CONCLUSIONS

DCS augmented intensive exposure therapy did not result in overall additional benefits relative to placebo. Intensive exposure proved effective in reducing symptoms for the overall sample.

Effects of delay of reinforcement on ABA renewal

ABA renewal was assessed by decreasing response rates by means of extinction or a 12-s delay of reinforcement in one experiment with rats. In a first phase, rats were trained to lever press for water in Context A. Rats were exposed to a second phase in Context B, where lever-pressing decreased for all rats; for one group of rats, lever-pressing decreased by means of extinction, while lever-pressing decreased by means of a 12-s delay for the other group. During a third phase, both groups were once again exposed to Context A with no reinforcer deliveries for lever-pressing. Once rats were exposed to the latter phase, renewal was observed for both groups. Results suggest that delay of reinforcement can be used as an alternative procedure to help reduce behavior and mitigate relapse.

An evaluation of a renewal-mitigation procedure for inappropriate mealtime behavior

Renewal, the increase in behavior during extinction following context changes, may be particularly concerning during intervention for feeding disorders because context changes are often necessary for intervention generality and maintenance (Podlesnik et al., 2017). In the current study, we tested for renewal and evaluated a renewal-mitigation procedure when we transferred intervention from a therapist to a caregiver, from clinic to the home, and changed the foods the feeder presented. We used an ABA arrangement to evaluate the generality of the renewal effect with 7 participants who engaged in inappropriate mealtime behavior. Context A was functional reinforcement. Context B was function-based extinction during the control and mitigation conditions and our renewal-mitigation procedure in the mitigation condition. The renewal test was function-based extinction in Context A. We observed renewal of inappropriate mealtime behavior in 4 of 7 participants, and our renewal-mitigation procedure was effective for 4 of 4 participants.

Conducting extinction in multiple contexts attenuates relapse of operant behavior in humans

In one experiment with human participants, we investigated the effects of using multiple contexts during extinction on the renewal of operant responses. Undergraduate students played a videogame in which they learned to shoot at enemies in Context A. Then, all participants experienced an extinction training. For half of the participants, extinction trials were conducted in a single context, whereas the other half received extinction in three different contexts. Finally, all participants were tested in Context A. We observed that conducting extinction in multiple contexts attenuated ABA renewal. The present results suggest that conducting extinction in multiple contexts can be used as a behavioral technique to reduce operant renewal.