情景变换诱发已消退恐惧记忆重现的神经环路

暴露疗法是治疗创伤后应激障碍的主要行为疗法。当被试反复暴露于可引起恐惧反应的条件刺激(如白噪音), 但却不伴有非条件刺激(如足底电击)时, 恐惧记忆将被消退, 形成消退记忆。但恐惧记忆并未从根本上被擦除, 当被试在消退训练以外的情景暴露于条件刺激时, 已消退的恐惧记忆将会重现。海马、内侧前额叶皮层、杏仁核等脑区及其相互连接的神经环路是情景诱发恐惧记忆重现的生理基础。情景变化诱发恐惧记忆重现过程中, 海马可能是通过直接投射至杏仁核基底核、杏仁核外侧核或通过边缘前皮质间接调控杏仁核基底核、杏仁核外侧核的功能, 产生恐惧反应。     

Monitoring–blunting coping styles and cognitive symptoms of dental fear

The present study investigates whether monitoring (i.e. vigilant) and blunting (i.e. avoidant) coping styles are associated with cognitive symptoms of dental fear. Results show that monitoring is positively related to the frequency and believability of negative thoughts about dental treatment, and negatively with the ability to control such thoughts. The opposite pattern is found for blunting. That is, blunting correlates negatively with the frequency and believability of negative thoughts, whereas a positive association emerges with cognitive control. These findings are in line with the Monitoring Process Model which proposes that ‘monitors’ (compared to ‘blunters’) generally show greater distress and arousal because of the way in which they cognitively elaborate threat.     

Childhood dental fear in relation to parental child-rearing attitudes

The aim of this study was to assess the relation between parental self-reported child-rearing attitudes and dental fear in children. The parents of 51 children with high dental fear and of 56 children with low dental fear, of different age groups, completed the Amsterdam version of the Parental Attitude Research Instrument. In addition, parents were asked to rate their own dental fear. Multivariate analysis of variance (child fear x parental fear x child age) showed a significant main effect only of child dental fear on parental self-complaints (p = .03). For parental dental fear, main effects were found on overprotection and on promotion of autonomy (p < or = .01). No age effects were found. Also, no relation between children's dental fear and parental dental fear was found. Based on the present findings, it was concluded that parents may play a more secondary, mediating role in the etiological process of dental fear in children.     

Determinants of early- vs late-onset dental fear in a longitudinal-epidemiological study.

A longitudinal investigation of risk factors for early- and late-onset dental fear was conducted. Early-onset dental fear was related to conditioning experiences (indexed via caries level and tooth loss), service use patterns, stress reactive personality and specific beliefs about health professionals. Late-onset dental fear was related to aversive conditioning experiences, irregular service use and an external locus of control. In contrast to recent findings for dental anxiety, personality factors were not strongly related to the onset of dental fear in young adulthood. The key role played by conditioning events in the development of both early- and late-onset dental fear was confirmed. Conditioning events appear to play a different role in the development of dental fear vs dental anxiety. This may reflect important, but largely ignored differences between these two closely-related constructs. Interventions for early-onset dental fear should aim to modify both the dental fear and the personality vulnerabilities that may contribute to the development of dental fear early in the life-course.     

Challenging anxious cognitions or accepting them? Exploring the efficacy of the cognitive elements of cognitive behaviour therapy and acceptance and commitment therapy in the reduction of children's fear of the dark

Anxiety is highly prevalent in pre-adolescent children. Distorted cognitions are characteristic for dysfunctional levels of anxiety. However, applying cognitive elements in pre-adolescent children cannot be fully ascertained, as it is not until adolescence before children can apply logical and abstract reasoning in a sophisticated manner. Cognitive behaviour therapy (CBT) and acceptance and commitment therapy (ACT) both target distorted cognitions. Whereas CBT encourages children to change the content of negative cognitions by applying cognitive restructuring, ACT stimulates youth to have a more accepting attitude towards these thoughts by applying cognitive defusion. The current study examined the efficacy of applying cognitive elements and compared the cognitive elements of CBT and ACT in pre-adolescent children. We included no behavioural elements to specifically study the developmental appropriateness of the cognitive elements in this age group. Highly anxious children, aged 8–12 years were randomised to a 30-minute cognitive restructuring (n = 21) or cognitive defusion intervention (n = 22). Subjective fear of the dark levels, behavioural darkness toleration, and comprehension and fun associated with the interventions were assessed. Both interventions had a significantly positive impact on children's fear of the dark. Cognitive restructuring led to more favourable results on subjective fear than cognitive defusion, no differences were found for darkness toleration.     

Manifestations, acquisition and diagnostic categories of dental fear in a self-referred population

This study aimed to clarify how manifestations and acquisition relate to diagnostic categories of dental fear in a population of self-referred dental fear patients, since diagnostic criteria specifically related to dental fear have not been validated. DSM III-R diagnostic criteria for phobias were used to compare with four existing dental fear diagnostic categories, referred to as the Seattle system. Subjects were 208 persons with dental fear who were telephone interviewed, of whom a subsample of 155 responded to a mailed Dental Anxiety Scale (DAS), State-Trait Anxiety Inventory and a modified FSS-II Geer Fear Scale (GFS). Personal interviews and a Dental Beliefs Scale of perceived trust and social interaction with dentists were also used to evaluate a subsample of 80 patients selected by sex and high dental fear. Results showed that the majority of the 80 patients (66%), suffered from social embarrassment about their dental fear problem and their inability to do something about it. The largest cause of their fear (84%) was reported to be traumatic dental experiences, especially in childhood (70%). A minority of patients (16%) could not isolate traumatic experiences and had a history of general fearfulness or anxiety. Analysis of GFS data for the 155 subjects showed that fear of snakes and injuries were highest among women; heights and injections among men. Fear of blood was rarely reported. Spearman correlations between GFS individual items and DAS scores indicated functional independence between dental fear and common fears such as blood, injections and enclosures in most cases. Only in specific types of dental fear did these results support Rachman and Lopatka's contention that fears are thought to summate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Adolescent dental fear and control: prevalence and theoretical implications.

This study examined the prevalence and etiology of dental fear in a large, representative sample of Singapore adolescents. Participants completed a questionnaire regarding fear of the dentist, dental beliefs and their most recent dental visit. The population prevalence of high dental fear was 115 fearful children per 1000 population (SE = 0.02). Children who reported painful treatment and perceived lack of control at the dentist were 13.7 times more likely to report high fear and 15.9 times less likely to be willing to return to the dentist or dental nurse. The etiology of severe clinical fear appears strongly related to direct conditioning in the presence of pain and vulnerability.     

Self-speech and self-regulation of high-and low-anxious children in the dental situation: An interview study

This study is conducted to assess children's self-speech and self-regulation during a dental visit. Forty children, aged 8–12 yr, were interviewed individually in the dental clinic. There were 20 children with high, phobic-like dental fear and 20 with low dental fear. Results showed that two-thirds of the children, equally distributed over high- and low-anxious children, reported self-speech. High dental fear was related to a specific type of self-speech, while low dental fear was not. Less than one-half of the children reported self-regulation. Level of fear was neither related to the occurrence nor the nature of the self-regulation. Moreover, the self-regulation, which the children reported, was not of the complex variety as described in various theoretical models.     

Components of dental fear in adults?

The functional relatedness between dental fear and multiple other fears was studied in a normative sample of 285 undergraduates. Rachman and Lopatka's work on the inter-dependence of multiple fears within individuals, as well as Lang's bioinformational theory of emotion, provided a theoretical background for this investigation. Fears about social contact, pain, mutilation (e.g. injury, blood, disfigurement), and being closed-in were assessed within the realm of verbal report; they were studied as possible components and/or concomitants of the dental fear construct. Multiple regression analyses with these variables utilized the Dental Fear Survey total score as a criterion variable. Fear of pain was found to be the most significant predictor of dental fear in both males and females. For females only, mutilation fear was the next strongest determinant. Fear of being closed-in was an additional significant dental fear predictor for both sexes. The possible role of social fears in the manifestation of dental fear was not confirmed and awaits further investigation. Results were consistent with the idea that there may often be a moderate degree of functional dependence between dental fear and the other fears identified here.     

Anxiety and immunologic disorder: phobia, generalized anxiety syndrome and panic attacks from the psychoimmunologic viewpoint with the intention of generating hypotheses]

From a behaviour therapist's viewpoint anxiety is perceived in a framework expanded to the psycho-neuro-immunological dimension. After describing phobic anxieties, cognitive mechanisms, and allergic-immunological disturbances, clinical experience won from 34 phobic patients treated with behavior therapy is demonstrated. 31 of these proved to be poly-allergic. A comparison of both physiological fear and allergic symptoms lets a relationship seem obvious between anaphylactic or collapse inclination and psychological fear reaction. Mediated by cognitive variables persons with emphatic perception may develop an association between anxiety and allergic processes with high probability, the reciprocal influence of which can increase with vehemence. Comprehensive psychologic-medical diagnostic and therapeutic measures could improve the effectivity of therapy as well as anxious patients' "compliance" and "coping skills".     

General and specific fears in referred and self-referred adult patients with extreme dental anxiety.

The levels of, and relationships between, dental fear and general fears and phobias were studied in 109 adult patients at a specialized dental fear clinic using two dental fear scales (the Dental Anxiety Scale and the Dental Fear Survey) together with the Fear Survey Schedule II (FSS-II) and some additional fear items. Referred and self-referred fearful dental patients answered mailed questionnaires in conjunction to being put on a 1 yr waiting list for treatment. Among feared objects and situations the separate item 'pain' revealed the highest mean scores for both men and women, followed by fear of suffocating, death of a loved one and sharp objects among women, and death of a loved one, suffocating and hypodermic needles among men. With few exceptions, women scored higher than men. The frequencies of extreme fears (6 and 7 on a 7-point scale) were high and 92.7% of the patients reported at least one extreme fear. Half of the subjects (49.5%) reported five fears or more. It was also shown that a number of FSS-II items correlated to dental fear indicating a relationship between general and dental fear. These results indicated that a large proportion of these dentally fearful individuals were prone to fear-associated reactions and behaviors, which has previously been shown to negatively influence the prognosis of treatment.     

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.     

The S-S construct of expectancy versus the S-R construct of fear: which motivates the acquisition of avoidance behavior?

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.     

Relaxation versus cognitive therapies for dental fear--a psychophysiological approach.

By separating 127 adult dental-phobic patients according to fear etiology and psychophysiologic response style, the authors investigated the outcome of 2 dental fear treatments. Before and after either relaxation or cognitively oriented treatment, subjects were exposed to neutral and fear-relevant video sequences while the subjects' forehead muscle tension, heart rate, and skin conductance were recorded. Pre- to postintervention differences in self-reported dental fear, general fear, and trait anxiety were analyzed together with psychophysiological data. Both treatments resulted in a significant reduction of dental fear. Despite significant interaction effects of Treatment Modality x Psychophysiological Response Style, it could not be concluded that patients with different fear etiologies or response styles benefit differentially from the 2 treatments given.     

Exposure to a novel context after extinction causes a renewal of extinguished conditioned responses: Implications for the treatment of fear

Renewal gives an experimental model for the relapse of fear symptoms following exposure therapy. While renewal of extinguished fear in humans has been observed following a return to the original context in which fear was acquired (ABA design), it has been more difficult to show upon presentation of a novel context (ABC design). The present experiment used a particularly strong context manipulation in a fear conditioning procedure. Context was manipulated by using large photographs of real environments taken from various angles and was present throughout the entire experiment. A renewal of cognitive expectancy was found in both ABA and ABC renewal designs, although it was larger in the former than in the latter. Response times in making the expectancy judgments increased when there was a change to a new context. The results demonstrate consistency in fear renewal effects between human and animal studies and suggest that relapse following exposure therapy via renewal remains a danger when people encounter a previously feared object in a novel context.     

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。     

A clinical study of child dental anxiety

Dental fear in children was studied using Rachman's theory of fear acquisition. Sixty children from two age groups (7-10 years, 11-14 years) participated in the project. The children were new patients attending a paediatric consultation clinic for specialised dental treatment. Thirty-one were diagnosed as being clinically anxious regarding dentistry and 29 were found to be nonanxious. Information regarding children's past experiences and present level of anxiety was obtained from the examining dentist, the children and their parents. Mothers were also interviewed and observed to ascertain their own anxieties and behaviour. The results showed that of Rachman's three pathways to fear, conditioning appeared largely responsible for the children's development of dental fear. Children's fear was more strongly associated with subjective experience of pain and trauma than with objective dental pathology. Indirect learning processes were found to be of only minor importance in this study.     

睡眠对恐惧学习的影响及其认知神经机制

睡眠问题可能会诱发恐惧相关情绪障碍(焦虑、创伤性应激障碍、恐怖症等),研究睡眠影响恐惧学习的认知神经机制,有助于增强对恐惧相关情绪障碍的预测、诊断和治疗。以往研究表明睡眠剥夺影响恐惧习得和消退主要是通过抑制vmPFC活动,阻碍其与杏仁核的功能连接,从而导致恐惧习得增强或是消退学习受损。进一步研究发现睡眠不同阶段对恐惧学习相关脑区有独特的影响:剥夺(缺乏)快速眼动睡眠会抑制vmPFC活动、增强杏仁核、海马激活,导致恐惧习得增强,消退学习受损,此外边缘皮层的功能连接减少破坏了记忆巩固(恐惧记忆和消退记忆);而慢波睡眠主要与海马变化有关,慢波睡眠期间进行目标记忆重激活可促进恐惧消退学习。未来研究需要增加睡眠影响恐惧泛化的神经机制研究、及昼夜节律中断对恐惧消退的影响,以及关注动物睡眠研究向人类睡眠研究转化中存在的问题。     

Cross-US reinstatement of human conditioned fear: Return of old fears or emergence of new ones?

Re-exposure to the unconditioned stimulus (US) following fear extinction in the laboratory produces reinstatement of fear. Similarly in clinical situations, anxiety patients may experience adverse events that reinstate fear following successful exposure therapy. The current study employed two USs, shock and loud noise, to examine whether a US that is qualitatively different but of the same valence as the original acquisition US can produce reinstatement in human fear conditioning. Both standard and cross-US reinstatement manipulations led to elevated fear as indexed by skin conductance. However, cross-US reinstatement was accompanied by elevated expectancy of the US that had been presented during the reinstatement manipulation, not the US that had been used to establish fear in acquisition. This result implies that reinstatement may involve the development of new fears. Context conditioning and cognitive processes were implicated as possible mechanisms. The current findings suggest that clinical relapse attributed to reinstatement may not always reflect the reactivation of old fears but may instead represent new fears worthy of clinical examination.     

Is pain sensitivity associated with dental avoidance?

The present investigation examined whether pain sensitivity is associated with dental avoidance. Whereas the aim of the first study was to determine whether pain sensitivity can be distinguished from dental fears and health concerns, the aim of the second study was to examine the structure of cognitive aspects of pain sensitivity, and the aim of the third study was to examine the relationships of pain sensitivity to anxiety sensitivity, fear, pain, and avoidance. In the first study (n = 222), a factor analysis performed with items from the Dental Phobia and Pain Sensitivity Inventory distinguished a pain sensitivity factor from factors relating to dental phobia and health concerns. The factor structure of the Pain Sensitivity Index was examined in the second study (n = 181), and similarly, a pain sensitivity factor was interpreted in the data. The third study (n = 65) found that although pain sensitivity correlated significantly with anxiety sensitivity, these constructs are not identical to each other. For instance, pain sensitivity but not anxiety sensitivity correlated significantly with blood-injury phobia. Pain sensitivity should be taken into account in future studies of dental phobia as pain sensitivity was found to be predictive of pain intensity, and pain intensity was found to be predictive of dental avoidance.