Return of fear after retrospective inferences about the absence of an unconditioned stimulus during extinction

We examined whether the effect of an extinction phase can be influenced retrospectively by information about the cause of the absence of the unconditioned stimulus (US) during that phase. Participants were subjected to a differential fear conditioning procedure, followed by an extinction procedure. Afterwards, half of the participants were presented with information about a technical failure, which explained why the US had been absent during the extinction phase. The other participants received information that was unrelated to the US. During a subsequent presentation of the target conditioned stimulus (CS), only the former group of participants showed renewed anticipatory skin conductance responding and a return of US expectancy. The results are in accordance with a propositional account of associative learning and highlight the importance of retrospective reasoning as a cause of relapse after exposure therapy.     

认知重评对负性效价的抑制促进条件性恐惧消退

认知重评能有效降低个体对情感刺激的负性情绪体验, 但指导性认知重评在恐惧记忆治疗中效果存在争议。本文将认知重评范式与辨别式条件恐惧反应范式结合, 以效价和US预期值为指标, 探讨指导性认知重评训练对恐惧情绪习得和消退的影响效果。以低认知重评能力个体为被试, 在实验前24 h进行指导性认知重评训练。条件性恐惧任务为期2天, 第一天完成条件性恐惧的习得和消退任务, 第二天完成条件性恐惧的再消退任务。结果显示, 经过重评训练后个体在条件性恐惧任务中的恐惧情绪效价显著较低, 说明认知重评有效降低低认知重评能力个体在急性应激状态下的负性情绪体验。所有被试均成功完成辨别式条件性恐惧的习得和消退任务, 因此重评训练并不削弱个体对危险或者安全信息的辨别能力。但在条件性恐惧的消退过程中, 认知重评指导训练加快了恐惧消退, 且24 h后测得的条件性恐惧程度显著较低, 说明指导性重评提高了条件性恐惧记忆的消退效率, 并减弱了条件性恐惧的消退返回。     

提取-消退范式中复合刺激对恐惧消退的影响

情绪障碍治疗的关键在于消退条件性恐惧记忆,研究证明基于记忆再巩固的提取-消退范式能有效消除或改写原有的恐惧记忆。本研究将提取-消退范式应用到更复杂的恐惧记忆中,采用多感官复合刺激(声音+图片)作为条件刺激,以皮电反应作为恐惧反应指标,考察采用单个线索(声音或图片)、复合线索(声音+图片)进行提取-消退对条件性恐惧记忆的消退效果有何差异。结果表明:声音线索提取-消退组出现了自发恢复和重建效应,图片提取-消退组只出现了重建效应,复合刺激提取-消退组未出现自发恢复和重建效应。说明由复合刺激线索引发的条件性恐惧,采用复合刺激中的单个较强线索或原有完整线索进行提取-消退,对恐惧记忆的消退效果最好。     

条件性恐惧提取消退的性别差异

基于记忆再巩固理论的提取消退范式能够有效地削弱非适应性恐惧记忆。性别差异是个体差异性研究的关键变量, 但在提取消退范式的研究中仍然比较少见关于性别差异的探索。因此本研究以立体几何图形作为条件刺激, 腕部电击作为非条件刺激, 皮肤电反应为恐惧反应指标, 探究提取消退范式在恐惧消退效果上是否存在性别差异。结果表明, 在恐惧自发恢复测试中, 提取消退范式的所有被试都成功抑制了恐惧复发, 但恐惧重建测试中只有女性被试抑制了恐惧复发。这说明, 提取消退范式在抑制恐惧自发恢复方面效果显著, 在恐惧重建上女性的消退效果显著优于男性。     

疼痛恐惧的形成、泛化与消退

疼痛恐惧源于把疼痛等同于伤害的灾难化信念及对疼痛的负性解释, 它在慢性疼痛和能力丧失的发生和发展过程中起着重要作用。疼痛恐惧可以通过联合学习和观察学习等方式获得, 并且在具有相似特征的刺激中存在泛化现象。通过教育干预和等级暴露疗法等可以成功消退疼痛恐惧, 在消退过程中要控制安全信息等因素的不良影响。在疼痛恐惧的获得与消退中, 主要有杏仁核, 脑岛和前扣带皮层等脑区参与。未来的研究可以集中在深入探讨疼痛恐惧形成中的泛化及消退后的恢复、再巩固等现象, 加强其临床上的应用, 并综合心理、生物和认知神经科学, 研究疼痛恐惧的获得、泛化与消退的深层机制。     

催产素影响恐惧习得和消退的认知神经机制

恐惧是一种基本的情绪, 在人类的生存和适应中发挥着重要作用。先前的研究表明, 杏仁核、背侧前扣带回、脑岛等脑区是条件化恐惧习得的认知神经基础, 杏仁核、海马和腹内侧前额叶等脑区在恐惧消退过程中发挥重要作用。研究发现, 催产素与恐惧习得和恐惧消退过程密切相关。恐惧习得过程中, 催产素影响杏仁核、背侧前扣带回的活动, 影响杏仁核与背侧前扣带回和脑干间的功能连接, 促进或抑制恐惧习得过程; 恐惧消退过程中, 催产素影响了杏仁核和腹内侧前额叶的活动, 并且影响杏仁核与内侧前额叶和海马间的功能连接, 促进或抑制恐惧消退过程。未来研究应从性别差异、神经网络模型、身心发育和病理研究等角度展开, 力图深入理解催产素影响恐惧情绪加工的认知神经机制。     

Associative learning versus fear habituation as predictors of long-term extinction retention

Violation of unconditioned stimulus (US) expectancy during extinction training may enhance associative learning and result in improved long-term extinction retention compared to within-session habituation. This experiment examines variation in US expectancy (i.e., expectancy violation) as a predictor of long-term extinction retention. It also examines within-session habituation of fear-potentiated startle (electromyography, EMG) and fear of conditioned stimuli (CS) throughout extinction training as predictors of extinction retention. Participants (n?=?63) underwent fear conditioning, extinction and retention and provided continuous ratings of US expectancy and EMG, as well as CS fear ratings before and after each phase. Variation in US expectancy throughout extinction and habituation of EMG and fear was entered into a regression as predictors of retention and reinstatement of levels of expectancy and fear. Greater variation in US expectancy throughout extinction training was significantly predictive of enhanced extinction performance measured at retention test, although not after reinstatement test. Slope of EMG and CS fear during extinction did not predict retention of extinction. Within-session habituation of EMG and self-reported fear is not sufficient for long-term retention of extinction learning, and models emphasizing expectation violation may result in enhanced outcomes.     

Failure to loose fear: The impact of cognitive load and trait anxiety on extinction

Exposure therapy is an effective technique for fear reduction. However, whether effective exposure requires attentional allocation to the feared situation remains a debated clinical issue. In the present study, the impact of attention allocation in extinction was investigated in an experimental conditioning study. Through a between-subjects manipulation of cognitive load, we created a condition in which participants could allocate their attention to the feared stimulus during extinction (low load condition), and a condition in which attentional allocation was impaired (high load condition). The influence of cognitive load on extinction was examined by comparing electrodermal responses and verbal ratings for the conditioned stimuli in the two extinction load conditions. The results show less successful extinction in the high load condition than in the low load condition. However, this effect was found only in low anxious participants, and it was prominent only on the skin conductance responses. The present results suggest that extinction is not automatic but requires cognitive resources.     

条件化恐惧复发的动物模型及相关神经机制

创伤后应激障碍(PTSD)受到国内外普遍关注, 临床上常用的暴露疗法就是基于消退原理, 但经过治疗的患者复发率仍然很高, 这提示抑制复发可能是治疗创伤后应激障碍的关键问题。条件性恐惧复发的动物模型主要包括重建、续新和自发恢复, 但是对续新的研究最多。前人的研究结果表明, 恐惧复发具有异质性, 但海马、前额叶与杏仁核三大脑区或许构成了共同的神经基础。文章从脑区机制及药理干预方面进行了综述, 以期对基础研究和临床诊治提供参考。     

Stronger renewal in human fear conditioning when tested with an acquisition retrieval cue than with an extinction retrieval cue

It was previously demonstrated in our laboratory that conditioned fear in humans can renew after extinction, when this procedure took place in a different context (ABA-renewal [Vansteenwegen et al. (2005). Return of fear in a human differential conditioning paradigm caused by a return to the original acquisition context. Behaviour Research and Therapy, 43(3), 323–336]). Using the same experimental design, we now tested the power of retrieval cues to interact with this contextual renewal phenomenon. Two groups went through acquisition and extinction (in a different context). They were then tested in the original acquisition context and in the presence of a retrieval cue. In the acquisition-cue group, this cue previously featured during the acquisition procedure; in the extinction-cue group, the cue previously featured during the extinction procedure. As expected, renewal of conditioned electro-dermal responding and retrospective expectancy ratings was strongest in the acquisition-cue group. Theoretical and clinical implications of this finding are discussed.     

预期错误在复合恐惧记忆提取消退中的作用

基于记忆再巩固理论的提取消退范式被证明是一种有效和颇有前景的消除不良记忆的方法。本研究将预期错误(Prediction Error, PE)应用于提取消退范式中, 采用多感官复合刺激模型(声音 + 图片)作为条件刺激, 以皮电反应作为恐惧反应指标, 考察在提取阶段不同的预期错误设置(无PE、单个负性PE、单个正性PE和多重PE)对条件性恐惧记忆提取消退效果有何差异。结果表明：无PE组和多重PE组出现了恐惧的自发恢复和重建效应, 而负性PE组和正性PE组均没有出现恐惧的自发恢复和重建效应。说明了在对复合恐惧记忆进行提取消退时, 提取阶段适当的PE才能使记忆进入再巩固过程, 随后传统消退达到抑制恐惧返回效果, 提取阶段没有PE或PE量过多都不能达到恐惧消退效果。     

条件性恐惧记忆消退的提取干预范式及其作用的神经机制

基于记忆再巩固理论的恐惧记忆提取干预范式被证明可以有效消退恐惧记忆, 能克服传统消退容易复发的缺点。该范式通过单独呈现条件刺激激活原有恐惧记忆, 使记忆重返不稳定状态, 随后在再巩固时间窗内实施干预则能改写原有记忆。目前该范式起作用的神经机制尚不明确, 本文在现有的人类研究和动物研究基础上, 总结了杏仁核、前额叶和海马三个脑区在提取干预过程中的作用, 以及该领域研究的争议点, 为之后的研究提供思路。     

Contextual control of the extinction of conditioned fear

Rats received 15 pairings of a CS and shock in one context, and then a series of CS-alone trials in a second context. Even though this extinction procedure produced a complete loss of conditioned suppression, when the animals were returned to the site of original conditioning, suppression was renewed to a level comparable to that of animals that had not undergone extinction. Controls indicated that the renewed suppression was not due solely to pseudoconditioning, suggesting that the CS-US association had survived extinction. Renewed suppression was also demonstrated in a third context that was never associated with shock. Loss of suppression did not necessarily depend upon inhibitory conditioning of the extinction context. The data suggest that extinction of conditioned fear is specific to the context in which it occurs. They also suggest the possibility that animals might discriminate episodes in which a CS is reinforced and nonreinforced independently of the excitatory or inhibitory status of cues, like contextual stimuli, that are coincidentally present during those episodes.     

Transfer of conditioned fear and avoidance: Concurrent measurement of arousal and operant responding

A reversal design was employed for the analysis of transfer of fear and avoidance through equivalence classes. Two 5-member equivalence classes (A1-B1-C1-D1-E1 and A2-B2-C2-D2-E2) were established. Then B1 and C1 were paired with shock (CS+) and served as S^Ds in avoidance training (B2 and C2 were trained as CS-/S^∆s for avoidance). Further avoidance training followed with D1 and E1 (as S^Ds) and D2 and E2 (as S^∆s), with the first presentation of each of these stimuli serving as the first transfer test. Afterwards, aversive conditioning contingencies were reversed: B2 and D2 were paired with shock and trained as S^Ds for avoidance, B1 and D1 were presented without shock (CS-/S^∆s). Transfer was tested again with C1, E1, C2 and E2. This reversal was implemented to allow for the within-subject replication of transfer effects upon changes in the function of only a subset of each class's elements. Avoidance (key presses) and conditioned fear (skin conductance and heart rate) were simultaneously measured. Results show a clear transfer effect for avoidance, with between- and within-subject replications. For physiological measures, transfer effects in the first test could only be imputed on the basis of group-based inferential statistical analysis. Evidence for between-subject replication was weaker, with only a limited proportion of participants meeting the individual criterion for transfer.     

Effects of multiple exposures to D-cycloserine on extinction of conditioned fear in rats

Previous research has shown that an acute, post-training injection of D-cycloserine (DCS) facilitates extinction of conditioned fear in rats; however, the effects of multiple exposures to DCS in this situation are not known. In Experiment 1, rats were conditioned (light-shock pairings) and 24 h later given six extinction (light-alone) trials followed by an injection of DCS (15 mg/kg) or saline. The next day, all rats were tested for light-elicited freezing. In Experiment 2, the effect of DCS on extinction was tested in the same manner, except that rats were pre-exposed to DCS (0, 1, or 5 injections) just prior to conditioning. In Experiment 3, rats received five pre-exposures of DCS but conditioning occurred either 2 or 28 days after the last pre-exposure. The results showed that DCS facilitated extinction of conditioned freezing to the light CS when no drug pre-exposure had occurred, but pre-exposure to DCS just prior to conditioning disrupted the facilitation of extinction effect. When 28 days were interposed between pre-exposure and conditioning, the facilitatory effects of DCS on extinction were restored. These findings suggest that DCS has significant clinical value but that behavioral desensitization may occur with multiple exposures; however, desensitization is not permanent and is reduced by the passage of time.     

The renewal of extinguished conditioned fear with fear-relevant and fear-irrelevant stimuli by a context change after extinction

The acquisition, extinction, and subsequent recovery of conditioned fear can be influenced by the nature of the conditional stimulus (CS) and the context in which the CS is presented. The combined effects of these factors were examined in a differential fear-conditioning procedure with humans. Fear-relevant or fear-irrelevant CSs were followed by a shock unconditional stimulus (US) during acquisition and presented alone during extinction. The CSs were images presented upon different background contexts. Half the participants received the same context during acquisition and extinction and the remaining received different contexts. All participants received test trials in the same context as acquisition. In Experiment 1 (N=64), a renewal of shock expectancy and skin conductance responses was found during test for fear-relevant and fear-irrelevant CSs when extinction was given in a different context. In Experiment 2 (N=72), renewal for fear-relevant stimuli was enhanced when acquisition and test was given in an indoor office context and extinction in an outdoor bush context. The opposite context configuration produced the strongest renewal for fear-irrelevant stimuli. The return of extinguished conditioned fear can occur to fear-relevant stimuli that are commonly associated with clinical fears and its strength may be enhanced when the stimuli are encountered in certain contexts after extinction.     

Return of fear in a human differential conditioning paradigm caused by a return to the original acquistion context

In a differential human fear conditioning paradigm evidence for ABA-renewal was obtained manipulating the lighting in the experimental room. During acquisition in either a dark or illuminated room, one neutral slide was sometimes paired with a loud aversive noise whereas another slide was not. Subsequently, extinction took place in the opposite lighting context. When afterwards the participants were tested again in the original acquisition context, measurements revealed a recovery of the conditioned electrodermal response and an increase in the retrospective verbal US-expectancy ratings. No response recovery was obtained in an AAA-group that received acquisition, extinction and test trials in one and the same context. Several theoretical explanations for this type of return of fear as well as implications for clinical practice are discussed.     

条件性恐惧泛化的性别差异

恐惧的过度泛化是焦虑障碍的核心症状之一, 表现为患者对与原危险刺激极不相似的中性刺激也有着较高强度的恐惧反应。临床上, 女性比男性更有可能患焦虑障碍, 因而对恐惧泛化进行性别差异研究可以为解释女性有着更高焦虑障碍发病率提供新的角度, 同时为临床治疗提供参考。本研究采用辨别性条件恐惧范式, 以主观预期值和皮电反应值作为测量指标, 从行为和生理两个层面对条件性恐惧泛化程度和恐惧泛化消退的性别差异进行研究。结果发现, 在恐惧泛化程度上, 未出现显著性别差异。在恐惧泛化消退上, 在主观预期值和皮电反应值两个层面均有着显著性别差异, 具体表现为相较于男性, 女性恐惧泛化的消退更慢, 持续时间更长。研究结果表明, 女性焦虑障碍高发病率的潜在影响因素之一可能在于女性对于恐惧泛化刺激的难以消除。     

Investigating the effectiveness of brief cognitive reappraisal training to reduce fear in adolescents

As adolescent anxiety is common and costly, identifying effective strategies to reduce symptoms is a priority. This study tested whether adolescents could learn to use cognitive reappraisal strategies to attenuate fear during extinction learning. Fifty-seven participants (12–15 years) viewed images of two neutral faces, one which was paired with a fearful expression and shrieking scream (conditioned threat stimulus) and the other that was never paired with the aversive outcome (conditioned safety stimulus) during fear acquisition. Before extinction, participants either received cognitive appraisal training, which explored alternative, benign meanings associated with the scream or a control activity. Self-reported fear ratings in the cognitive reappraisal group were significantly lower to both the conditioned threat and safety stimuli after extinction than the control group. These findings did not characterise fear-potentiated startle data. Potential reasons for the lack of consistency between measures are considered.     

The repeated confrontation with videotapes of spiders in multiple contexts attenuates renewal of fear in spider-anxious students

In a treatment-analogue experiment, extinction of fear of spiders was investigated in a group of spider-anxious students. Two groups were created: in the single extinction group the extinction trials consisted of repeated presentations of a videotaped spider in one specific location of a house, whereas in the multiple extinction group the trials consisted of videotapes of the same spider in three different locations of a house. Also a control group was included that was exposed to videotapes of the location but without the spider. As reflected in skin conductance responses and self-report data, fear of spiders was significantly reduced in the two extinction groups compared to the control group. Moreover, when the extinction groups were confronted with the videotape of the spider in a new location, the single extinction group did not show generalisation of extinction, whereas the multiple extinction group did. These results corroborate the existing evidence for context dependence of extinction of fear and provide new evidence that the use of multiple contexts during extinction might improve the generalisability of extinction in humans. Implications for exposure therapy are discussed.