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Recent studies have shown that fear conditioning experiments can be successfully conducted online. However, there is limited evidence that measures other than subjective ratings of threat expectancy can be collected, which means that online research may not be able to adequately replace laboratory experiments. In the current study, we conducted an online fear conditioning experiment consisting of habituation, acquisition, extinction and 48 h delayed extinction recall using ratings of threat expectancy and conditional stimulus pleasantness, and probe reaction time as outcome measures. The conditional stimuli were categories of words and a levels of processing manipulation explored whether words that were processed at a deeper level during extinction evoked smaller differential threat responses during extinction recall. Although the levels of processing manipulation did not produce a significant outcome, we found that extinction recall was successfully operationalised in our study. Reaction time indicated differential responding during both acquisition and extinction recall, and age of participants was correlated in one of two experiments with differential threat expectancy and reaction time, such that older participants showed better safety learning. The outcomes of this experiment provide multiple novel tools for researchers to explore fear conditioning, especially in an online environment., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Recent studies have shown that extinction training including the conditional stimulus (CS+) and stimuli that are similar to the CS + enhances extinction retention and generalisation to novel stimuli. However, in a clinical setting, the CS+ is rarely available for use during exposure therapy. The aim of the present study was to determine if replacing the CS+ with a similar versus different stimulus, and including other similar stimuli during extinction, could reduce fear at test on par with extinction using the original CS+ with and without other similar stimuli. In an experiment conducted in a single session, participants completed a habituation phase followed by an acquisition phase using two dog images presented with (CS+) and without (CS-) an acoustic unconditional stimulus (US). Participants were randomly allocated to four extinction conditions: similar CS + dog with novel dog images (Similar replacement extinction condition); different CS + dog with novel dog images (Different replacement extinction condition); original CS + dog with novel dog images (Multiple extinction control condition); and original CS + without novel dog images (Standard extinction control condition). All participants completed a test phase with the original CSs followed by a generalisation test with another two novel dog images. All groups acquired, and then extinguished differential skin conductance responses (SCRs) with no differences observed between groups. Whereas the Similar replacement extinction group and the Multiple and Standard extinction control groups did not exhibit significant differential SCRs when re-exposed to the original CS + relative to the CS- at test, differential responding to the CSs was significant at test in the Different replacement extinction group. There were no significant differences between groups in SCRs to the two novel dog images during the generalisation phase and in between-phase subjective ratings. Findings suggest that replacement stimuli used during extinction should be as similar as possible to the CS + to reduce physiological arousal to the original CS+., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Social anxiety disorder (SAD) is associated with marked physiological reactivity in social-evaluative situations. However, objective measurement of biomarkers is rarely evaluated in treatment trials, despite potential utility in clarifying disorder-specific physiological correlates. This randomized controlled trial sought to examine the differential impact of imagery-enhanced vs. verbal-based cognitive behavioral group therapy (IE-CBGT, n = 53; VB-CBGT, n = 54) on biomarkers of emotion regulation and arousal during social stress in people with SAD (pre- and post-treatment differences in heart rate variability (HRV) and skin conductance). We acquired psychophysiological data from randomized participants across four social stress test phases (baseline, speech preparation, speech, interaction) at pre-treatment, and 1- and 6-months post-treatment. Analyses revealed that IE-CBGT selectively attenuated heart rate as indexed by increases in median heart rate interval (median-RR) compared to VB-CBGT at post-treatment, whereas one HRV index showed a larger increase in the VB-CBGT condition before but not after controlling for median-RR. Other psychophysiological indices did not differ between conditions. Lower sympathetic arousal in the IE-CBGT condition may have obviated the need for parasympathetic downregulation, whereas the opposite was true for VB-CBGT. These findings provide preliminary insights into the impact of imagery-enhanced and verbally-based psychotherapy for SAD on emotion regulation biomarkers., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

A growing literature has sought to combine fear conditioning paradigms with the trauma film paradigm to study the associative learning properties of intrusive re-experiencing in PTSD. We review this innovative approach and the recent findings by highlighting their relevance to cognitive and conditioning theories of PTSD. We also conduct a meta-analysis of the available studies to demonstrate that, for most outcome measures, fear learning using a traumatic film clip unconditional stimulus yields results similar to those seen with an electro-tactile unconditional stimulus, which implies that the combined paradigm shares at least some properties of more standard fear conditioning paradigms. We argue that careful use of this combined paradigm will provide important new insights into the mechanisms underlying memory symptoms of PTSD and will allow rigorous testing of cognitive theories of the disorder., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Recent studies have shown that extinction training including the conditional stimulus (CS+) and stimuli similar to the CS + enhances extinction retention and generalisation to novel stimuli. The aim of the present study was to confirm that these effects are specific to presenting stimuli similar to the CS+ during extinction and not merely an effect of additional trials or additional stimuli unrelated to the CS+. In an experiment conducted in a single session on the same day, participants (134 adults; 70.7% female; 17-40 years of age, M = 20.04, SD = 4.36) completed a habituation phase followed by an acquisition phase using dog images presented with (CS+) and without (CS-) a dog growl paired with a scream unconditional stimulus (US). Participants were randomly allocated to four extinction conditions: Multiple exemplar extinction comprising the CSs and two novel dog images similar to the CS+; Standard extinction control matched for the number of CS+ and CS- presentations; Extended extinction control matched for the total number extinction trials, and Other stimuli extinction control comprising the CSs and two novel stimuli unrelated to the CS+. All participants completed an extinction test with the original CSs followed by a generalisation test with two novel dog images. Multiple, Standard and Other stimuli extinction groups exhibited larger skin conductance responses (SCRs) during extinction to the CSs compared to the Extended extinction group. SCRs to the additional dog images in the Multiple group were larger than SCRs to the additional CSs in the Extended group and the novel images in the Other stimuli group. There were no group differences in responses to the CSs during extinction test. Unlike the other groups, SCRs to the first presentation of the novel generalisation dogs did not differ from those to the last CS trials in extinction in the Multiple group. However, this group difference did not persist beyond the initial generalisation trial. Finally, the Multiple, Extended, and Other stimuli groups exhibited more negative CS evaluations after extinction, extinction test, and generalisation test than the Standard extinction group. The results suggest that extinction with the original CSs and additional stimuli resembling the CS + elevated physiological responses during extinction and reduced physiological responses to novel stimuli similar to the CSs. Further studies are needed including clinical samples and trial-by-trial evaluations of the stimuli presented., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Since Watson and Rayner's (1920) initial demonstration that human fear can be learned by means of Pavlovian conditioning, neuroscientific and behavioral studies have provided a thorough understanding of fear acquisition. Less is known about the manner in which we can harness insights from Pavlovian conditioning research to reduce fears and, most importantly, make the reduction of fear lasting and resistant against relapse. The current paper reviews three manipulations that have shown promise in achieving a reduction of conditional fear that is more resistant to relapse than is the reduction of conditional fear after standard extinction: novelty-facilitated extinction training, presentation of conditional-unconditional stimulus pairings or of unpaired unconditional stimuli during extinction, and extinction with additional stimuli that are similar to the original conditional stimuli. It summarizes past research involving human and non-human animal subjects and highlights knowledge gaps in the current literature. Moreover, it discusses potential mechanisms that mediate the reduction of fear seen as a result of these manipulations in an attempt to enhance our understanding of what renders fear extinction less vulnerable to the known pathways to fear relapse. It is hoped that this review will contribute to the achievement of the goal that was denied to Watson and Rayner, the development of experimental techniques that can be utilized to remove conditioned emotional responses permanently., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Motor actions can be released much sooner than normal when the go-signal is of very high intensity (>100 dBa). Although statistical evidence from individual studies has been mixed, it has been assumed that sternocleidomastoid (SCM) muscle activity could be used to distinguish between two neural circuits involved in movement triggering. We summarized meta-analytically the available evidence for this hypothesis, comparing the difference in premotor reaction time (RT) of actions where SCM activity was elicited (SCM+ trials) by loud acoustic stimuli against trials in which it was absent (SCM- trials). We found ten studies, all reporting comparisons between SCM+ and SCM- trials. Our mini meta-analysis showed that premotor RTs are faster in SCM+ than in SCM- trials, but the effect can be confounded by the variability of the foreperiods employed. We present experimental data showing that foreperiod predictability can induce differences in RT that would be of similar size to those attributed to the activation of different neurophysiological pathways to trigger prepared actions. We discuss plausible physiological mechanisms that would explain differences in premotor RTs between SCM+ and SCM- trials., (Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.)

Although contemporary treatments for anxiety disorders are very efficient in reducing anxiety, return of fear after successful treatment is common which signifies a need for interventions that have a more enduring outcome. A recent laboratory study suggested that novelty-facilitated extinction, a simple modification of standard extinction which involves presenting a novel non-aversive stimulus during extinction, prevents spontaneous recovery, one laboratory analogue of return of fear. The current study assessed whether novelty-facilitated extinction can also prevent reinstatement, a second laboratory analogue of return of fear. Following differential fear conditioning, one group of participants underwent standard extinction training whereas the second was presented with a novel tone after the conditional stimulus that previously predicted the aversive unconditional stimulus (US). Three presentations of the USs alone reinstated differential electrodermal fear responses after standard extinction, but not after novelty-facilitated extinction. Moreover, replicating previous findings, the extent of return of fear was correlated with self-reported intolerance of uncertainty after standard extinction, but not after novelty-facilitated extinction. These results support the proposal that novelty-facilitated extinction training can reduce the extent of return of fear., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Fears underlying anxiety disorders are commonly treated with exposure-based therapies, which are based on the principles of extinction learning. While these treatments are efficacious, fears may return after successful treatment. Past research suggested that post-extinction recovery of fear could be reduced through extinction training that involves occasional presentations of the aversive unconditioned stimulus (US), paired with the conditioned stimulus (CS). Here, we examined whether extinction training with occasionally paired or unpaired US presentations is superior in the reduction of fear recovery to non-reinforced extinction., Method: Following differential fear conditioning to neutral cues, participants (N = 72; M age = 21.61 years, SD = 3.95) underwent either non-reinforced, partially reinforced, or unpaired extinction training., Results: Extinction involving paired or unpaired US presentations, but not non-reinforced extinction, eliminated spontaneous recovery of differential skin conductance responses (SCRs). Results further suggested that unpaired, but not paired, US presentations may guard against rapid reacquisition of differential SCRs. No benefits of US presentations during extinction were found on the reinstatement of SCRs or recovery of differential negative CS+ valence., Conclusion: Presenting USs during extinction training was more effective than non-reinforced extinction in the reduction of fear recovery, as indexed by SCRs, with unpaired extinction being more effective than partially reinforced extinction., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

In associative learning, if stimulus A is presented in the same temporal context as the conditional stimulus (CS) - outcome association (but not in a way that allows an A-CS association to form) it becomes a temporal context cue, acquiring the ability to activate this context and retrieve the CS-outcome association. We examined whether a CS- presented during acquisition or extinction that predicted the absence of the unconditional stimulus (US) could act as a temporal context cue, reducing or enhancing responding, in differential fear conditioning. Two groups received acquisition (CSx-US, CSa-noUS) in phase 1 and extinction (CSx-noUS; CSe-noUS) in phase 2 (AE groups), and two groups received extinction in phase 1 and acquisition in phase 2 (EA groups). After a delay, participants were presented with either CSa (AEa and EAa groups) or CSe (AEe and EAe groups). Responding to CSx was enhanced after presentation of CSa but reduced after presentation of CSe, suggesting that training was segmented into two learning episodes and that the unreinforced CS present during an episode retrieved the CSx-US or CSx-noUS association. These findings suggest that temporal context cues may enhance or reduce fear responding, providing an exciting new avenue for relapse prevention research., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Extant literature suggests that extinction training delivered during the memory reconsolidation period is superior to traditional extinction training in the reduction of fear recovery, as it targets the original fear memory trace. At present it is debated whether different types of fear memories are differentially sensitive to behavioral manipulations of reconsolidation. Here, we examined post-reconsolidation recovery of fear as a function of conditioned stimulus (CS) fear-relevance, using the unconditioned stimulus (US) to reactivate and destabilize conditioned fear memories. Participants (N = 56; 25 male; M = 24.39 years, SD = 7.71) in the US-reactivation and control group underwent differential fear conditioning to fear-relevant (spiders/snakes) and fear-irrelevant (geometric shapes) CSs on Day 1. On Day 2, participants received either reminded (US-reactivation) or non-reminded extinction training. Tests of fear recovery, conducted 24 h later, revealed recovery of differential electrodermal responding to both classes of CSs in the control group, but not in the US-reactivation group. These findings indicate that the US reactivation-extinction procedure eliminated recovery of extinguished responding not only to fear-irrelevant, but also to fear-relevant CSs. Contrasting previous reports, our findings show that post-reconsolidation recovery of conditioned responding is not a function of CS fear-relevance and that persistent reduction of fear, conditioned to fear-relevant CSs, can be achieved through behavioral manipulations of reconsolidation., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Relapse of fear after successful intervention is a major problem in clinical practice. However, little is known about how it is mediated. The current study investigated the effects of instructed extinction and removal of the shock electrode on electrodermal responding (Experiment 1), fear potentiated startle (Experiment 2), and a continuous self-report measure of conditional stimulus valence (Experiments 1 and 2) in human differential fear conditioning. Instructed extinction and removal of the shock electrode resulted in the immediate reduction of differential fear potentiated startle and second interval electrodermal responding, but did not affect self-reported conditional stimulus valence. A separate sample of participants (Experiment 3) who were provided with a detailed description of the experimental scenario predicted the inverse outcome, reduced differential stimulus evaluations and continued differential physiological responding, rendering it unlikely that the current results reflect on demand characteristics. These results suggest that the negative valence acquired during fear conditioning is less sensitive to cognitive interventions than are the physiological indices of human fear learning and that valence reduction requires extended exposure training. Persisting negative valence after cognitive intervention may contribute to fear relapse after successful treatment., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Empathy is an important pro-social behaviour critical to a positive client-therapist relationship. Therapist anxiety has been linked to reduced ability to empathise and lower client satisfaction with therapy. However, the nature of the relationship between anxiety and empathy is currently unclear. The current study investigated the effect of experimentally-induced anxiety on empathic responses elicited during three different perspective-taking tasks. Perspective-taking was manipulated within-subjects with all participants (N=52) completing imagine-self, imagine-other and objective conditions. A threat of shock manipulation was used to vary anxiety between-subjects. Participants in the threat of shock condition reported higher levels of anxiety during the experiment and lower levels of empathy-related distress for the targets than participants in the control condition. Perspective-taking was associated with higher levels of empathy-related distress and concern compared to the objective condition. The present results suggest that perspective-taking can to a large extent mitigate the influence of heightened anxiety on an individual's ability to empathise., (Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.)

We investigated the effects of awareness on selective attention for masked and unmasked verbal threat material using a computerised version of the emotional Stroop. Participants were assigned to the high trait anxious (HTA) and low trait anxious (LTA) groups on the basis of questionnaire scores, and state anxiety was manipulated within participants through the threat of electric shock. To investigate the effects of awareness on responses to threat, the mode of exposure was blocked such that half the participants received masked trials before the unmasked trials, whereas the other half received the reverse order. The results revealed that there was no difference between the HTA and LTA groups in responses to threat for those who received the masked trials before the unmasked trials. However, when unmasked trials were presented before the masked trials HTA individuals were significantly slower to respond to both masked and unmasked threat words compared to the LTA group, and these effects were not further modified by participants' state anxiety status. The results are discussed in terms of the automatic nature of threat processing in anxiety., (2009 Elsevier Ltd. All rights reserved.)

The current research assessed the effects of verbal instruction on affective and expectancy learning during repeated contingency reversals (Experiment 1) and during extinction (Experiment 2) in a picture-picture paradigm. Affective and expectancy learning displayed contingency reversal and extinction, but changes were slower for affective learning. Instructions facilitated reversal and extinction of expectancy learning but did not impact on affective learning. These findings suggest a differential susceptibility of affective and expectancy learning to verbal instruction and question previous reports that verbal instructions can accelerate the extinction of non-prepared fear learning in humans., (2009 Elsevier Ltd. All rights reserved.)

Aversive conditioning and extinction were evaluated in children with anxiety disorders (n=23), at-risk for anxiety disorders (n=15), and controls (n=11). Participants underwent 16 trials of discriminative conditioning of two geometric figures, with (CS+) or without (CS-) an aversive tone (US), followed by 8 extinction trials (4 CS+, 4 CS-), and 8 extinction re-test trials averaging 2 weeks later. Skin conductance responses and verbal ratings of valence and arousal to the CS+/CS- stimuli were measured. Anxiety disordered children showed larger anticipatory and unconditional skin conductance responses across conditioning, and larger orienting and anticipatory skin conductance responses across extinction and extinction re-test, all to the CS+ and CS-, relative to controls. At-risk children showed larger unconditional responses during conditioning, larger orienting responses during the first block of extinction, and larger anticipatory responses during extinction re-test, all to the CS+ and CS-, relative to controls. Also, anxiety disordered children rated the CS+ as more unpleasant than the other groups. Elevated skin conductance responses to signals of threat (CS+) and signals of safety (CS-; CS+ during extinction) are discussed as features of manifestation of and risk for anxiety in children, compared to the specificity of valence judgments to the manifestation of anxiety.

The present study demonstrated that pictures of fear-relevant animals, snakes and spiders, presented among backgrounds of other animal stimuli captured attention and interfered in the detection of a neutral target to the same extent in a large sample of unselected children (N=81). Moreover, detection of a neutral target animal was slowed more in the presence of a feared fear-relevant distracter, e.g., a snake for snake fearful children, than in the presence of a not feared fear-relevant distracter, e.g., a spider for snake fearful children. These results indicate attentional capture by phylogenetically fear-relevant animal stimuli in children and the selective enhancement of this effect by fear of these animals. These findings are consistent with current models of preferential processing of phylogenetically prepared threat stimuli and with cognitive models of anxiety that propose an enhancing effect of fear in the processing of fear-related stimuli.

The renewal of Pavlovian-conditioned responses may provide a model for the relapse of fear following extinction-based treatments for anxiety disorders. Renewal can be observed if conditional stimulus (CS) and unconditional stimulus (US) pairings are given in one context, extinction trials of CS presentations in a second context, prior to test trials of CS presentations in the original acquisition context (ABA renewal). We examined ABA renewal in humans by using a fear-conditioning procedure with an unpleasant shock US. A renewal of rated shock expectancy was demonstrated with this procedure. Conducting extinction treatment in multiple contexts was expected to attenuate the renewal effect. However, the renewal of shock expectancy persisted when extinction treatment was given across three or five different contexts. With the current renewal design, learning task, and measure of conditioned behaviour, extinction treatment does not appear to readily generalise to the test context. The use of multiple extinction treatments in a clinical setting may not necessarily reduce the likelihood of relapse via a renewal effect.

The habituation to intense acoustic stimuli and the acquisition of differentially conditioned fear were assessed in 53 clinically anxious and 30 non-anxious control children and young adolescents. Anxious children tended to show larger electrodermal responses during habituation, but did not differ in blink startle latency or magnitude. After acquisition training, non-anxious children rated the CS+ as more fear provoking and arousing than the CS- whereas the ratings of anxious children did not differ. However, anxious children rated the CS+ as more fear provoking after extinction, a difference that was absent in non-anxious children. During extinction training, anxious children displayed larger blink magnitude facilitation during CS+ and a trend towards larger electrodermal responses, a tendency not seen in non-anxious children. These data suggest that extinction of fear learning is retarded in anxious children.