状态焦虑对条件恐惧习得和消退的影响

采用44名正常女性大学生作为被试, 通过心理社会压力暴露的方法诱发焦虑组被试的状态焦虑, 采用主观预期值作为指标, 考察焦虑对条件恐惧习得和消退的直接影响, 并探讨这种影响是否也表现在评价性条件作用上。结果表明：心理社会压力暴露显著提高了焦虑组被试的状态焦虑。在习得阶段, 状态焦虑降低了被试对条件刺激的辨别条件恐惧反应, 具体而言, 状态焦虑降低了被试对CS+的主观预期值, 但是却提高了对CS?的主观预期值; 在消退阶段, 状态焦虑抑制了被试对条件刺激的消退。状态焦虑的影响也表现在评价性条件作用上, 和控制组相比, 焦虑组在习惯化和消退阶段对条件刺激表现出了更为负性的效价评定。     

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。     

他人在场抑制条件性恐惧泛化

本研究采用经典的知觉辨别恐惧条件反射范式,将主观电击预期和皮肤电反应作为主要指标,考察他人在场对恐惧习得过程和恐惧泛化程度的影响。结果发现,恐惧习得过程未出现显著的组间差异。在恐惧泛化上,他人在场抑制了恐惧泛化水平,表现为皮肤电泛化水平更低、泛化梯度更广。研究初步证明,他人在场可能会分散个体的注意资源,降低个体的知觉辨别能力,进而抑制恐惧泛化。因此,他人在场在临床上对情绪障碍,特别是恐惧和焦虑相关障碍群体的干预作用值得重视。     

积极情绪对条件性恐惧泛化的抑制作用

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安全刺激也产生恐惧反应。本研究采用经典条件恐惧范式,以US主观预期、回溯性恐惧评定、回溯性效价评定和皮电反应作为恐惧反应的指标,通过"最好自我"训练来诱发被试的积极情绪,考察了恐惧习得后的积极情绪对于恐惧泛化的影响。本研究发现,积极情绪能有效地抑制条件性恐惧的泛化,增强被试对安全信号的学习,并对消退后的恐惧重建现象起到预防作用。研究同时显示,恐惧泛化在主观评定指标和生理指标间出现了分离,这表明积极情绪对恐惧泛化的抑制作用是一个综合的过程,可能涉及到不同的作用机制。本研究结果提示可以通过诱发积极情绪,抑制条件性恐惧的泛化,对临床干预有一定的启发意义。     

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。     

非条件刺激降低再评估对条件性恐惧消退的影响

诸多情绪障碍治疗的关键在于促进条件性恐惧反应的消退, 研究证明非条件刺激再评估能够引起恐惧反应的变化。本研究将非条件刺激降低再评估范式应用于消退训练, 以主观预期值、皮电反应作为恐惧反应指标, 考察恐惧习得后非条件刺激强度降低对条件性恐惧消退的影响, 并运用评价性条件作用探讨非条件刺激再评估的作用机制。结果表明：在消退阶段, 降低组对条件刺激的皮电反应显著低于控制组。同时评价性条件作用结果显示：经过非条件刺激再评估, 降低组较控制组对条件刺激的评价更为正性。说明非条件刺激降低再评估有效改变条件刺激的负性效价, 降低个体的恐惧反应、促进恐惧消退。     

分类和概念对恐惧泛化的影响机制

恐惧泛化与多种焦虑障碍的病理基础密切相关。例如创伤后应激障碍个体往往持续地逃避与创伤事件有关的刺激,遭受着创伤痛苦折磨。本文在厘清知觉辨别与恐惧泛化关系的基础上,着力于高级认知过程(分类与概念相似性、典型性和人工概念)对恐惧泛化的影响,回顾了恐惧泛化的相关神经机制,并揭示恐惧泛化对焦虑障碍患者的临床治疗启示。未来研究应将知觉和高级认知维度的恐惧泛化进行整合研究,同时扩充恐惧习得和泛化的神经回路,以促进人类恐惧泛化更深入的研究。     

自悯写作对恐惧消退的促进作用

先前研究表明,自悯干预能够改善焦虑相关精神疾病的心理症状,然而自悯改善焦虑的作用机制尚不清楚。以恐惧消退为基础的暴露疗法是治疗焦虑症的关键疗法,研究自悯干预如何促进恐惧消退从而增强暴露疗法的效果有助于阐释暴露疗法的作用机制。本研究共56名有效健康被试,在恐惧习得之后,将匹配自悯水平和焦虑水平的被试随机分配进行自悯写作或非自悯日常写作,最后进行恐惧消退测试,并通过检测写作前后的正负性情绪变化以及恐惧消退早期、晚期的电击预期反应和皮肤电反应来探究自悯写作对恐惧消退的影响及其作用机制。结果显示,两种写作任务均降低了被试的负性情绪;相比于非自悯日常写作,自悯写作显著降低了被试在恐惧消退早期和晚期的对威胁和安全线索的电击预期反应。相比于消退晚期,自悯组消退早期的皮肤电反应更弱。这一结果表明,自悯写作能够调节对威胁和安全线索的反应来促进恐惧消退。本研究首次运用实验室恐惧消退模型探讨自我怜悯调节威胁刺激的加工机制,有助于解释自悯改善焦虑症状的心理和生理机制,并强调了在基于恐惧消退范式的暴露疗法中增加认知干预的必要性。     

恐惧学习的发展认知神经机制研究回顾与展望

恐惧可以帮助个体快速地评估危险情景,并调动生理和行为反应来应对危险刺激。恐惧发展始于婴儿时期,神经回路表现为杏仁核未参与恐惧反应,但杏仁核功能连接可以预测早期恐惧反应;发展到童年期的恐惧学习特点为安全学习不足和过度泛化,其根源是负责辨别刺激的海马还处于发育中;进入青春期恐惧加工主要特征是由于前额叶发育较晚导致的消退能力弱。恐惧虽有益于人类生存,但恐惧异常会引发焦虑障碍,本文从恐惧的习得、消退和泛化三个阶段,对比了焦虑与健康青少年的恐惧学习差异。最后,文章从增加婴儿时期研究、创新青少年恐惧研究范式和开发安全有效的干预手段三个方面对未来研究提出展望,以期进一步推动恐惧研究的发展。     

基于知觉的恐惧泛化的认知神经机制

恐惧泛化是条件性恐惧反应转移到另一个相似但安全的刺激的现象。适当的恐惧泛化对人类有积极意义, 而过度的恐惧泛化则不利于个体有效地适应环境。基于知觉的恐惧泛化研究揭示了恐惧泛化的规律, 因而被广泛应用。本文首先梳理了对知觉恐惧泛化的相关研究, 介绍恐惧泛化的经典理论基础—巴普洛夫条件反射以及恐惧泛化梯度; 其次简要回顾基于多个感觉通道(即视觉、听觉、情景)的知觉恐惧泛化研究现状; 再次, 分别对海马、杏仁核、脑岛和前额叶等脑区在恐惧泛化中的作用进行回顾, 进一步总结出恐惧泛化的神经环路结构模型。最后, 简要区分了基于知觉的恐惧泛化和正在兴起的基于概念的恐惧泛化, 进而指出未来研究需要结合基于概念的恐惧泛化、区分被试对刺激的辨别力、增加恐惧刺激材料的准确性及多样化、结合激素等个体差异和多模态脑成像数据来展开。     

Pavlovian Disgust Conditioning and Generalization: Specificity and Associations With Individual Differences

Although studies have identified differences between fear and disgust conditioning, much less is known about the generalization of conditioned disgust. This is an important gap in the literature given that overgeneralization of conditioned disgust to neutral stimuli may have clinical implications. To address this knowledge gap, female participants (n = 80) completed a Pavlovian conditioning procedure in which one neutral food item (conditioned stimulus; CS+) was followed by disgusting videos of individuals vomiting (unconditioned stimulus; US) and another neutral food item (CS–) was not reinforced with the disgusting video. Following this acquisition phase, there was an extinction phase in which both CSs were presented unreinforced. Importantly, participants also evaluated generalization stimuli (GS+, GS?) that resembled, but were distinct from, the CS after each conditioning phase. As predicted, the CS+ was rated as significantly more disgusting and fear inducing than the CS? after acquisition and this pattern persisted after extinction. However, disgust ratings of the CS+ after acquisition were significantly larger than fear ratings. Participants also rated the GS+ as significantly more disgusting, but not fear inducing, than the GS? after acquisition. However, this effect was not observed after extinction. Disgust proneness did predict a greater increase in disgust and fear ratings of the CS+ relative to the CS? after acquisition and extinction. In contrast, trait anxiety predicted only higher fear ratings to the CS+ relative to the CS? after acquisition and extinction. Disgust proneness nor trait anxiety predicted the greater increase in disgust to the GS+ relative to the GS? after acquisition. These findings suggest that while conditioned disgust can generalize, individual difference variables that predict generalization remain unclear. The implications of these findings for disorders of disgust are discussed.     

Generalization of conditioned fear-potentiated startle in humans: experimental validation and clinical relevance

Though generalization of conditioned fear has been implicated as a central feature of pathological anxiety, surprisingly little is known about the psychobiology of this learning phenomenon in humans. Whereas animal work has frequently applied methods to examine generalization gradients to study the gradual weakening of the conditioned-fear response as the test stimulus increasingly differs from the conditioned stimulus (CS), to our knowledge no psychobiological studies of such gradients have been conducted in humans over the last 40 years. The current effort validates an updated generalization paradigm incorporating more recent methods for the objective measurement of anxiety (fear-potentiated startle). The paradigm employs 10, quasi-randomly presented, rings of gradually increasing size with extremes serving as CS+ and CS−. The eight rings of intermediary size serve as generalization stimuli (GSs) and create a continuum-of-similarity from CS+ to CS−. Both startle data and online self-report ratings demonstrate continuous decreases in generalization as the presented stimulus becomes less similar to the CS+. The current paradigm represents an updated and efficacious tool with which to study fear generalization—a central, yet understudied conditioning-correlate of pathologic anxiety.     

Fearing shades of grey: individual differences in fear responding towards generalisation stimuli

Individual differences in fear generalisation have been proposed to play a role in the aetiology and/or maintenance of anxiety disorders, but few data are available to directly support that claim. The research that is available has focused mostly on generalisation of peripheral and central physiological fear responses. Far less is known about the generalisation of avoidance, the behavioural component of fear. In two experiments, we evaluated how neuroticism, a known vulnerability factor for anxiety, modulates an array of fear responses, including avoidance tendencies, towards generalisation stimuli (GS). Participants underwent differential fear conditioning, in which one conditioned stimulus (CS+) was repeatedly paired with an aversive outcome (shock; unconditioned stimulus, US), whereas another was not (CS?). Fear generalisation was observed across measures in Experiment 1 (US expectancy and evaluative ratings) and Experiment 2 (US expectancy, evaluative ratings, skin conductance, startle responses, safety behaviours), with overall highest responding to the CS+, lowest to the CS? and intermediate responding to the GSs. Neuroticism had very little impact on fear generalisation (but did affect GS recognition rates in Experiment 1), in line with the idea that fear generalisation is largely an adaptive process.     

Generalization of extinguished skin conductance responding in human fear conditioning

In a human fear conditioning paradigm using the skin conductance response (SCR), participants were assigned to two groups. Following identical acquisition, group ABA (n = 16) was extinguished to a generalization stimulus (GS), whereas group AAB (n = 20) was extinguished to the conditioned stimulus (CS). At test, presenting the CS in group ABA yielded a strongly recovered SCR. Presenting the GS in group AAB, on the other hand, did not disrupt the effects of extinction. We conclude that extinguishing the CS (group AAB) is an efficient strategy to overcome the stimulus specificity of extinction observed otherwise (group ABA). Clinical implications are discussed.     

对条件化恐惧反应的抑制效应:指导性与习惯性情绪调节的作用

为了考察实验室指导性与个体习惯性情绪调控策略对恐惧反应的影响,先使用问卷调查了81名大学生的习惯性重评与抑制水平,随后将被试分为两组,指导其在条件化恐惧习得过程中进行主动的情绪调节或自然观看,24h后进行恐惧的表达测试。结果发现,习惯性抑制水平与恐惧习得及表达水平呈显著负相关,且指导性情绪调节与习惯性抑制均显著降低了恐惧习得及表达水平。这提示指导性与习惯性情绪调节策略均能够削弱应激的伤害以保护个体。     

Electrometric Studies of Sleep

The authors provided a differential test between stimulus-stimulus (S-S) and stimulus-response (S-R) theory predictions in regard to the roles that the constructs of expectancy and of fear play in maintaining classically conditioned fear responding within the context of a human conditioned-avoidance paradigm. After the participants had developed sustained avoidance responding, their shock electrodes and avoidance response apparatus were removed to enhance the cognitive expectancy that the conditioned stimulus (CS) would not be followed by the unconditioned stimulus (UCS). This manipulation of expectancy was successful in 96% of the participants. The study was conducted over a 2-day period and involved 1 experimental group and 3 control groups. During the test trials, the authors used autonomic and self-report indices of fear to assess the presence or absence of fear to the CS. The data disconfirmed the prediction of the S-S theory that fear to the CS would be extinguished. The authors discuss the implications of this finding for S-S theories and for approaches in cognitive behavior therapy.