Search

In this human fear conditioning study, the online development of conditioned US-expectancy to discrete cues and background contexts was measured in two groups. In the paired group (n = 30), the CS was systematically followed by an aversive shock (US). In the unpaired group (n = 30), CS and US were presented explicitly unpaired. Using US-expectancy ratings, we replicated the basic finding already illustrated in humans with startle modulation. In the paired group, the CS elicited more US-expectancy than the context, whereas in the unpaired group, the context elicited more US-expectancy than the CS. Interestingly, we also observed a trial-by-trial development of conditioning to the context in the unpaired group as indicated by a significant linear trend. This gradual development and the evidence for the role of US-expectancy in contextual fear add to the idea that cued and contextual fear rely on the same basic associative processes.

Fear extinction is a reduction in conditioned fear responses following repeated exposure to the feared cue in the absence of any aversive event. Exposure treatments for anxiety disorders such as posttraumatic stress disorder can be conceptualized as clinical analogues of extinction. Extinguished fear often reappears over time after extinction, an occurrence known as spontaneous recovery. Recent animal studies from our group suggest that spontaneous recovery can be abolished if extinction occurs within minutes of fear acquisition. To date, the limited number of human studies of fear extinction have shown that short interval extinction does not prevent the return of conditioned fear. For this reason, we performed an in-depth parametric analysis of human fear extinction using fear- potentiated startle measures. We employed both single cue and differential conditioning paradigms in which participants were fear conditioned by repeatedly pairing a colored light (conditioned stimulus) and an aversive airblast to the throat (unconditioned stimulus). Participants were then extinguished either 10 min (Immediate) or 72 hr (Delayed) later. Testing for spontaneous recovery occurred 96 hr after acquisition in both groups. In the single cue paradigm, subjects in the Immediate and Delayed groups exhibited differences in context conditioning but not fear conditioning. In the differential conditioning paradigm, there were no differences in context

In a human fear conditioning experiment, with on-line expectancy ratings and electrodermal responding as indices of fear, two neutral stimuli (pictures of geometric shapes) were first established as reliable predictors of an electric shock. In the subsequent extinction phase, the two stimuli were repeatedly presented in compound, without the shock. The final test phase consisted of individual stimulus presentations again, which resulted in a strong return of the conditioned responses. This effect was not observed in non-conditioned control stimuli. Hence, behavioral effects of extinction seem highly specific to the stimulus constellation that has gone through the extinction procedure. We argue that pharmacological, behavioral and/or cognitive manipulations that could prevent configural processing of stimulus constellations have direct clinical potential.

Clinical fear of spiders was assessed in 39 patients before and after exposure treatment and at a 3-month follow-up. The assessment included behavioral, physiological and self-report measures. Some patients were tested in the treatment context (group Same), while others were tested in a different context (group Different). Both groups demonstrated a significant fear reduction from pre- to post-treatment in all measures, which persisted at the 3-month follow-up. Contrary to our expectations, no clear difference was observed between the groups at any moment. However, a 1-year follow-up test of the self-report measure revealed a return of fear in group Same, but not in group Different. These results show (1) that the effects of exposure treatment persisted over contexts and time in the short term, and (2) that conducting treatment and tests in different contexts enhanced efficiency of exposure treatment in the long term.

Associative learning plays an important role in the development of anxiety disorders, but a thorough understanding of the variables that impact such learning is still lacking. We investigated whether individual differences in autobiographical memory specificity are related to discrimination learning and generalization. In an associative learning task, participants learned the association between two pictures of female faces and a non-aversive outcome. Subsequently, six morphed pictures functioning as generalization stimuli (GSs) were introduced. In a sample of healthy participants (Study 1), we did not find evidence for differences in discrimination learning as a function of memory specificity. In a sample of anxiety disorder patients (Study 2), individuals who were characterized by low memory specificity showed deficient discrimination learning relative to high specific individuals. In contrast to previous findings, results revealed no effect of memory specificity on generalization. These results indicate that impaired discrimination learning, previously shown in patients suffering from an anxiety disorder, may be – in part – due to limited memory specificity. Together, these studies emphasize the importance of incorporating cognitive variables in associative learning theories and their implications for the development of anxiety disorders. In addition, re-analyses of the data (Study 3) showed that patients suffering from panic disorder showed higher outcome expectancies in the presence of the stimulus that was never followed by an outcome during discrimination training, relative to patients suffering from other anxiety disorders and healthy participants. Because we used a neutral, non-aversive outcome (i.e., drawing of a lightning bolt), these data suggest that learning abnormalities in panic disorder may not be restricted to fear learning, but rather reflect a more general associative learning deficit that also manifests in fear irrelevant contexts. ispartof: Frontiers in Psychology vol:6 pages:1-12 ispartof: location:Switzerland status: published

Potentially life-threatening interoceptive sensations easily engage the behavioral defensive system. Resulting fear and anxiety toward interoceptive threat are functionally distinct states that are hypothesized to play a prominent role in the etiology of panic disorder. The present study aimed to investigate whether fear- and anxiety-potentiated startle responses occur to predictable and unpredictable interoceptive threat, respectively. Therefore, we modified the NPU threat test (SchmitzGrillon, ) and replaced the aversive electrocutaneous stimulus with an aversive interoceptive stimulus (a breathing occlusion, making it briefly impossible to breathe). Healthy participants (N = 48) underwent three instructed conditions. A visual cue signaled the occlusion in the predictable condition (P), whereas another cue was unrelated to the occurrence of the occlusion in the unpredictable condition (U). The safe condition (N) also had a visual cue, but no occlusion. Both fear- and anxiety-potentiated startle blink responses were observed in response to predictable and unpredictable respiratory threat, respectively. The current study presents and validates the NPU respiratory threat test (NPUr) as an ecologically valid paradigm to study both anxiety and fear in response to a panic-relevant interoceptive threat. The paradigm allows future testing of contextual generalization, investigation of different clinical groups, and more explicit comparisons of defensive responding to interoceptive versus exteroceptive threats.

Despite the effectiveness of exposure therapy for treating anxiety disorders, a number of patients fail to benefi t or experience a return of fear after treatment. Research suggests that anxious individuals show defi cits in the mechanisms believed to underlie exposure therapy, such as inhibitory learning. Targeting these processes may help improve the effi cacy of expo- sure-based procedures. The primary aim of this paper is to provide examples to clinicians for how to apply this model to optimize exposure therapy with anxious clients, in ways that distinguish it from a "fear habituation" approach and "belief disconfi rma- tion" approach within standard cognitive-behavior therapy. Exposure optimization strategies include 1) expectancy violation, 2) deepened extinction, 3) occasional reinforced extinction, 4) removal of safety signals, 5) variability, 6) retrieval cues, 7) multiple contexts, and 8) affect labeling. Case studies illustrate methods of applying these techniques with a variety of anxiety disorders.

To account for disparate findings in the literature on automatic evaluation, Gawronski, Rydell, Vervliet, and De Houwer (2010) proposed a representational theory that specifies the contextual conditions under which automatic evaluations reflect initially acquired attitudinal information or subsequently acquired counterattitudinal information. The theory predicts that automatic evaluations should reflect the valence of expectancy-violating counterattitudinal information only in the context in which this information had been learned. In contrast, automatic evaluations should reflect the valence of initial attitudinal information in any other context, be it the context in which the initial attitudinal information had been acquired (ABA renewal) or a novel context in which the target object had not been encountered before (ABC renewal). The current article presents a meta-analysis of all published and unpublished studies from the authors' research groups regardless of whether they produced the predicted pattern of results. Results revealed average effect sizes of d = 0.249 for ABA renewal (30 studies, N = 3,142) and d = 0.174 for ABC renewal (27 studies, N = 2,930), both of which were significantly different from zero. Effect sizes were moderated by attention to context during learning, order of positive and negative information, context-valence contingencies during learning, and sample country. Although some of the obtained moderator effects are consistent with the representational theory, others require theoretical refinements and future research to gain deeper insights into the mechanisms underlying contextual renewal.

A marked signature of fear extinction is its vulnerability for relapse. Here, we departed from the standard extinction principle and examined the ability of habituation to reduce conditioned fear reactions and prevent relapse. In a human fear conditioning paradigm, we first established one visual stimulus as a signal for an impending aversive electrical stimulation, while another visual stimulus was never followed by this stimulation. Next, the screen color changed and participants were either exposed to the visual stimuli without electrical stimulation (extinction treatment) or to the electrical stimulation without the visual stimuli (habituation treatment). Finally, the screen color changed back and the two visual stimuli were tested. Verbal ratings showed a return of conditioned shock-expectancy in the two groups, while skin conductance reactivity showed conditioned discrimination following exposures to the visual stimuli, but not following exposures to the electrical stimulation. We conclude that an habituation treatment outperforms an extinction treatment, and that shock-expectancy and skin conductance can dissociate under some conditions. publisher: Elsevier articletitle: Beyond extinction: Habituation eliminates conditioned skin conductance across contexts journaltitle: International Journal of Psychophysiology articlelink: http://dx.doi.org/10.1016/j.ijpsycho.2014.11.010 content_type: article copyright: Copyright © 2014 Elsevier B.V. All rights reserved. ispartof: International Journal of Psychophysiology vol:98 issue:3 pages:529-534 ispartof: location:Netherlands status: published

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.

The purpose of this study was to analyze fear extinction and reinstatement in humans using fear-potentiated startle. Participants were fear conditioned using a simple discrimination procedure with colored lights as the conditioned stimuli (CSs) and an airblast to the throat as the unconditioned stimulus (US). Participants were extinguished 24 h after fear conditioning. Upon presentation of unsignaled USs after extinction, participants displayed significant fear reinstatement. In summary, these procedures produced robust fear-potentiated startle, significant CS+/CS− discrimination, within-session extinction, and significant reinstatement. This is the first demonstration of fear extinction and reinstatement in humans using startle measures.

Two experiments investigated the perceptual generalization of acquisition and extinction in human contingency learning. In Experiment 1, the degree of perceptual similarity between the acquisition stimulus and the generalization stimulus was manipulated over five groups. This successfully generated a generalization gradient of acquisition. In the subsequent phase, the response to the generalization stimulus was extinguished in each group. Finally, the acquisition stimulus was presented again. The response recovered differently over groups, thereby establishing the generalization gradient of extinction. In Experiment 2, the acquisition stimulus itself was extinguished before the set of generalization stimuli was tested between groups. One group evidenced a response recovery at test, which suggests that the gradient of acquisition is somewhat broader than the gradient of extinction.

A well-demonstrated phenomenon in traditional Pavlovian conditioning research with humans is that of experimental extinction. In contrast, human evaluative conditioning research suggests that evaluative learning shows marked resistance to extinction. Here, the authors replicate both findings concurrently. Two differential fear conditioning experiments with an electrocutaneous stimulus as the unconditioned stimulus evidenced (a) sensitivity to extinction using an autonomic skin-conductance measure and (b) complete resistance to extinction using an affective-priming measure. The results corroborate the idea that evaluative conditioning is more resistant to extinction than is expectancy learning (F. Baeyens, P. Eelen, & G. Crombez, 1995).

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.

Using a conditioned suppression task, we investigated simultaneous (XA−/A+) vs. sequential (X → A−/A+) Feature Negative (FN) discrimination learning in humans. We expected the simultaneous discrimination to result in X (or alternatively the XA configuration) becoming an inhibitor acting directly on the US, and the sequential discrimination in X becoming a negative occasion setter acting indirectly on the A–US link. After simultaneous FN training, X+ training completely abolished discriminative XA/A responding (Experiment 1), and X transferred inhibition to new targets B regardless of their training history (B+ or YB−/B+) (Experiment 2), suggesting X became a simple inhibitor. After sequential FN training, X showed the predicted selective transfer to a target B that also had been modulated (Y → B−/B+), not to a simple excitor (B+) (Experiment 4), but turning X into an excitor (X+) likewise disrupted discriminative X → A/A responding (Experiment 3). This suggests that X acquired a combination of modulatory and direct inhibitory properties, and that the joint contribution of both components is necessary for the suppression of the target-induced US activation.

Exposure therapy is an effective approach for treating anxiety disorders, although a substantial number of individuals fail to benefit or experience a return of fear after treatment. Research suggests that anxious individuals show deficits in the mechanisms believed to underlie exposure therapy, such as inhibitory learning. Targeting these processes may help improve the efficacy of exposure-based procedures. Although evidence supports an inhibitory learning model of extinction, there has been little discussion of how to implement this model in clinical practice. The primary aim of this paper is to provide examples to clinicians for how to apply this model to optimize exposure therapy with anxious clients, in ways that distinguish it from a 'fear habituation' approach and 'belief disconfirmation' approach within standard cognitive-behavior therapy. Exposure optimization strategies include (1) expectancy violation, (2) deepened extinction, (3) occasional reinforced extinction, (4) removal of safety signals, (5) variability, (6) retrieval cues, (7) multiple contexts, and (8) affect labeling. Case studies illustrate methods of applying these techniques with a variety of anxiety disorders, including obsessive-compulsive disorder, posttraumatic stress disorder, social phobia, specific phobia, and panic disorder. publisher: Elsevier articletitle: Maximizing exposure therapy: An inhibitory learning approach journaltitle: Behaviour Research and Therapy articlelink: http://dx.doi.org/10.1016/j.brat.2014.04.006 content_type: article copyright: Copyright © 2014 Elsevier Ltd. All rights reserved. ispartof: Behaviour Research and Therapy vol:58 pages:10-23 ispartof: location:England status: published

Fear generalization, in which conditioned fear responses generalize or spread to related stimuli, is a defining feature of anxiety disorders. The behavioral consequences of maladaptive fear generalization are that aversive experiences with one stimulus or event may lead one to regard other cues or situations as potential threats that should be avoided, despite variations in physical form. Theoretical and empirical interest in the generalization of conditioned learning dates to the earliest research on classical conditioning in nonhumans. Recently, there has been renewed focus on fear generalization in humans due in part to its explanatory power in characterizing disorders of fear and anxiety. Here, we review existing behavioral and neuroimaging empirical research on the perceptual and non-perceptual (conceptual and symbolic) generalization of fear and avoidance in healthy humans and patients with anxiety disorders. The clinical implications of this research for understanding the etiology and treatment of anxiety is considered and directions for future research described.

Adaptive anxiety relies on a balance between the generalization of fear acquisition and fear extinction. Research on fear (extinction) generalization has focused mostly on perceptual similarity, thereby ignoring the importance of conceptual stimulus relations in humans. The present study used a laboratory procedure to create de novo conceptual categories of arbitrary stimuli and investigated fear and extinction generalization among these stimuli. A matching-to-sample task produced two four-member categories of abstract figures. Next, a member from one category was coupled with an aversive electrical stimulation, while a member from the other category was presented alone. As expected, conditioned fear responses generalized to the other members of the first category (skin conductance and online shock-expectancy). Subsequent extinction of the conditioned member also generalized to the other members. However, extinguishing a non-conditioned member failed to reduce fear of the conditioned member itself. We conclude that fears generalize readily across conceptually related stimuli, but that the degree of extinction generalization depends on the stimulus subjected to extinction. ispartof: PLoS One vol:9 issue:5 ispartof: location:United States status: published

Background and Objectives: The degree of (over)generalization (to the self, over situations) is an important characteristic of depression and anxiety disorders. Little is known about cognitive mechanisms underlying this (over)generalization. In this context, the present study examined the effect of an abstract processing style (compared to a more concrete processing style) on generalization of angry faces to the self. An abstract processing style refers to thoughts about the meaning, causes and consequences of events or situations (‘Why’-thinking). Methods: To test the impact of an abstract processing experimentally, images of angry faces were paired with the name of the participant and happy faces were paired with another person’s name while participants adopted either an abstract (‘Why’) or a concrete (‘How’) processing style. A surprise recognition task, where participants were asked to indicate whether they had seen the faces before, served as a test of generalization of angry faces to the self. Results: Results indicated that participants who adopted an abstract processing style showed more generalization of angry faces to the self and a trend towards more generalization of happy faces to the other person, relative to participants who adopted a concrete processing style. Limitations: Our sample was a non-clinical student sample and thus conclusions about the generalizability to clinical samples should be done with caution. Conclusions: These results suggest that abstract thought may underlie the generalization of bad/failure/angry feelings toward the self (‘Everyone is always angry with me’) and of good feelings towards other people (‘Everyone is always nicer to other people’) that is often seen in depression and social anxiety disorder. publisher: Elsevier articletitle: “Why is everyone always angry with me?!”: When thinking ‘why’ leads to generalization journaltitle: Journal of Behavior Therapy and Experimental Psychiatry articlelink: http://dx.doi.org/10.1016/j.jbtep.2014.11.008 content_type: article copyright: Copyright © 2014 Elsevier Ltd. All rights reserved. ispartof: Journal of Behavior Therapy and Experimental Psychiatry vol:47 pages:34-41 ispartof: location:Netherlands status: published

The peak of learned responding normally occurs at the learning stimulus itself, but can shift to a different stimulus after discriminative learning. This provides important information about the nature of the generalization mechanism, and reveals alternative pathways through which learned responses can increase. Over two experiments, we established the peak-shift effect in a human predictive learning paradigm. Participants were asked to predict the occurrence of a neutral outcome (drawing of a lightning bolt) based on preceding geometrical figures (rings of different sizes). During learning, the middle-sized ring was sometimes followed by the outcome, whereas a larger ring was never followed by the outcome. At test, we presented larger and smaller rings (Experiment 1), or only a slightly smaller ring (Experiment 2). We consistently observed highest prediction of the outcome to the slightly smaller ring. Predictive estimations in humans can reach their height to stimuli that have never actually participated in the learning experiences. We argue that the results are most in line with an associative learning account, rather than an adaptation-level or a rule-learning account.

Although enhanced fear conditioning has been implicated in the origins of social anxiety disorder (SAD), laboratory evidence in support of this association is limited. Using a paradigm employing socially relevant unconditioned stimuli, we conducted two separate studies to asses fear conditioning in individuals with SAD and non-clinical individuals with high social anxiety (subclinical social anxiety [SSA]). They were compared with age-matched and gender-matched individuals with another anxiety disorder (panic disorder with agoraphobia) and healthy controls (Study 1) and with individuals with low social anxiety (Study 2). Contrary to our expectations, in both studies, self-report measures (ratings of anxiety, unpleasantness and arousal to the conditioned stimuli) of fear conditioning failed to discriminate between SAD or SSA and the other participant groups. Our results suggest that enhanced fear conditioning does not play a major role in pathological social anxiety.We used a social conditioning paradigm to study fear conditioning in clinical and subclinical social anxiety. We found no evidence of enhanced fear conditioning in social anxiety individuals. Enhanced fear conditioning may not be a hallmark of pathological social anxiety.

Little is known about the role of discrete stimulus features in the regulation of fear. This study examined the effects of feature learning on the acquisition and extinction of fear conditioning. Human participants were fear conditioned to a yellow triangle (CS+) using an electrical shock. We manipulated feature learning through differential conditioning. The nonconditioned control stimulus (CS−) was a red triangle in one group (Color-Relevant), but a yellow circle in the other group (Shape-Relevant). Next, two generalization stimuli were tested that shared the shape- or color-feature with the CS+ (a blue triangle and a yellow square). Online shock-expectancy ratings and skin conductance responding showed that the CS− determined the pattern of fear generalization: the same-color stimulus elicited more fear in Group Color-Relevant, versus the same-shape stimulus in group Shape-Relevant. Furthermore, extinguishing these two generalization stimuli had no detectable effect on fear of the CS+. These results show that fear generalization is influenced by feature learning through differential conditioning, and that exposures to different features of a stimulus are not sufficient to extinguish fear of that stimulus as a whole.

Prevention is better than cure, but little is known about effective prevention of anxiety disorders. Individuals vulnerable for trauma-exposure would benefit from effective techniques to prevent the development of post-traumatic stress. One reason for the apparent standstill in this literature may be the exclusive focus on the development of fear, while pre-clinical anxiety treatment research has turned to impaired extinction of fear as the main mechanism underlying abnormal anxiety. Conditioning theories propose latent inhibition as a technique to prevent the development of fears, but the effects on fear extinction have not been examined in detail. I conducted two experiments to evaluate the effects of latent inhibition on extinction in a standard human fear conditioning paradigm, which serves as a model for post-traumatic stress disorder. Skin conductance reactivity and online expectancy ratings revealed slower rates of fear acquisition in the latent inhibition groups, as well as a speeded extinction effect early in extinction. However, extinction of expectancy ratings was less complete in the latent inhibition groups. The beneficial effects of the latent inhibition technique may be in promoting early success of self-exposures or exposure treatment and motivating the patient to continue on the exposure path

ispartof: Biological Psychology vol:92 issue:1 pages:1- ispartof: location:Netherlands status: published

Individuals seem to differ in conditionability, i.e., the ease by which the contingent presentation of two stimuli will lead to a conditioned response. In contemporary learning theory, individual differences in the etiology and maintenance of anxiety disorders are, among others, explained by individual differences in temperamental variables (Mineka and Zinbarg, 2006). One such individual difference variable is how people process a learning experience when the conditioning stimuli are no longer present. Repeatedly thinking about the conditioning experience, as in worry or rumination, might prolong the initial (fear) reactions and as such, might leave certain individuals more vulnerable to developing an anxiety disorder. However, in human conditioning research, relatively little attention has been devoted to the processing of a memory trace after its initial acquisition, despite its potential influences on subsequent performance. Post-acquisition processing can be induced by mental reiteration of a conditioned stimulus-unconditioned stimulus (CS-US)-contingency. Using a human conditioned suppression paradigm, we investigated the effect of repeated activations of a CS-US-contingency memory on the level of conditioned responding at a later test. Results of three experiments showed more sustained responding to a "rehearsed" CS+ as compared to a "non-rehearsed" CS+. Moreover, the second experiment showed no effect of rehearsal when only the CS was rehearsed instead of the CS-US-contingency. The third experiment demonstrated that mental CS-US-rehearsal has the same effect regardless of whether it was cued by the CS and a verbal reference to the US or by a neutral signal, making the rehearsal "purely mental." In sum, it was demonstrated that post-acquisition activation of a CS-US-contingency memory can impact conditioned responding, underlining the importance of post-acquisition processes in conditioning. This might indicate that individuals who are more prone to mentally rehearse information condition more easily. ispartof: Frontiers in Psychology vol:4 issue:MAY pages:305-305 ispartof: location:Switzerland status: published

Background The metabolic challenge of trauma disrupts hippocampal functioning, which is necessary for processing the complex co-occurring elements comprising the traumatic context. Poor contextual memory of trauma may subsequently contribute to intrusive memories and overgeneralization of fear. Glucose consumption following trauma may be a means to protect hippocampal functioning and contextual fear learning. This study experimentally examined the effect of glucose on hippocampal-dependent contextual learning versus cued fear learning in humans. Methods Forty-two male participants underwent cued conditioning with an unconditional stimulus (US) (shock) paired with a discrete conditional stimulus (geometric shape) and context conditioning (requiring hippocampal processing) with a US unpredictably paired with a background context (picture of room). Participants were then blindly randomized to consume either a 25 g glucose or sweet-tasting placebo drink and returned for a test phase 24 hours later. Measures included acoustic startle response, US expectancy, blood glucose levels, and arousal ratings. Results The glucose group showed superior retention of hippocampal-dependent contextual learning at test relative to the placebo group, as demonstrated by acoustic startle response and US expectancy ratings. Glucose and placebo groups did not differ on any measure of cued fear learning at test. Conclusions This study provides experimental evidence that in mildly stressed humans postconditioning glucose consumption improves retention of hippocampal-dependent contextual learning but not cued learning. Ultimately, glucose consumption following trauma may be a means of improving learning about the traumatic context, thereby preventing subsequent development of symptoms of posttraumatic stress.

Return of fear following successful exposure therapy is a common problem. More insight into the characteristics of extinction learning is crucial in enhancing the efficiency of therapeutic interventions. In particular, understanding the mechanisms that underlie the generalization of extinction learning to other discrete stimuli is indispensable. Presently, little is known about the molecular and genetic mechanisms underlying this phenomenon. In this study, we attempt to develop a new conditioning protocol to study return of fear, caused by a stimulus change after extinction, in the most commonly used mouse strain of behavioral genetics, C57BL/6J. Perceptual changes to an auditory fear conditioned stimulus led to return of fear after initially successful fear-reduction, relative to appropriate control treatment. We argue that this protocol will be a useful tool to unravel the neurobiological underpinnings that regulate generalization of extinction and return of fear. Key questions for future research include the identification of crucial brain structures, neurotransmitters and signaling pathways that underly this behavioral phenomenon. Arguably, such research will open up new perspectives for neurobiological therapy augmentation.

At the core of anxiety disorders is the inability to use contextual information to modulate behavioral responses to potentially threatening events. Models of the pathogenesis of anxiety disorders incorporate stress and concomitant stress hormones as important vulnerability factors, while others emphasize sex as an important factor. However, translational basic research has not yet investigated the effects of stress hormones and sex on the ability to use contextual information to modulate responses to threat. Therefore, the purpose of the present study was threefold: first, we aimed at developing an experimental paradigm specifically capable of capturing contextual modulation of the expression of fear. Second, we tested whether cortisol would alter the contextualization of fear expression. Third, we aimed at assessing whether alterations in contextualization due to cortisol were different for men and women. Healthy participants (n = 42) received placebo or hydrocortisone (20 mg) prior to undergoing a newly developed differential contextual fear-conditioning paradigm. The results indicated that people rapidly acquire differential contextual modulation of the expression of fear, as measured by fear potentiated startle (FPS) and skin conductance responses (SCR). In addition, cortisol impaired the contextualization of fear expression leading to increased fear generalization on FPS data in women. The opposite pattern was found in men. Finally, as assessed by SCR, cortisol impaired differential conditioning in men. The results are in line with models suggesting heightened vulnerability in women for developing anxiety disorders after stressful events. ispartof: Frontiers in behavioral neuroscience vol:6 issue:67 pages:1-14 ispartof: location:Switzerland status: published

The main behavioral signature of fear extinction is its fragility. This is exemplified by the renewal effect, where a change in the background context produces recovery of fear to a conditioned-and-extinguished stimulus. Renewal is the backbone of a widely accepted theory of extinction in animal research, as well as an important experimental model to screen novel treatment techniques. This has led to an explosion of fear renewal research in humans. However, the mere observation of return of fear in a renewal procedure is not sufficient to validate this particular theory of extinction in the tested sample/procedure. Here, we systematically outline a set of experimental tests that aid in evaluating alternative extinction/renewal mechanisms. We examine published renewal studies in human fear conditioning and conclude that the prevailing theory of extinction is often taken for granted, but critical tests are lacking. Including these tests in future research will not only reveal the fear extinction mechanism in humans, but also inspire further developments in extinction treatment research.

Research has shown that automatic evaluations can be highly robust and difficult to change, highly malleable and easy to change, and highly context dependent. We tested a representational account of these disparate findings, which specifies the conditions under which automatic evaluations reflect (a) initially acquired information, (b) subsequently acquired, counterattitudinal information, or (c) a mixture of both. The account postulates that attention to contextual cues during the encoding of evaluative information determines whether this information is stored in a context-free representation or a contextualized representation. To the extent that attention to context cues is low during the encoding of initial information but is enhanced by exposure to expectancy-violating counterattitudinal information, initial experiences are stored in context-free representations, whereas counterattitudinal experiences are stored in contextualized representations. Hence, automatic evaluations tend to reflect the valence of counterattitudinal information only in the context in which this information was learned (occasion setting) and the valence of initial experiences in any other context (renewal effect). Four experiments confirmed these predictions, additionally showing that (a) the impact of initial experiences was reduced for automatic evaluations in novel contexts when context salience during the encoding of initial information was enhanced, (b) context effects were eliminated altogether when context salience during the encoding of counterattitudinal information was reduced, and (c) enhanced context salience during the encoding of counterattitudinal information produced context-dependent automatic evaluations even when there was no contingency between valence and contextual cues. Implications for automatic evaluation, learning theory, and interventions in applied settings are discussed.

Generalization of acquired responses appears to be a crucial, yet under investigated process in emotional disorders. Generalization occurs when a conditioned response is elicited by a stimulus different from the original conditioned stimulus. The expansion of complaints, often seen in emotional disorders, is at least in part due to processes of generalization. In the present study, generalization is approached from a memory perspective. It is hypothesized that generalization of conditioned responding is associated with autobiographical memory specificity. Higher levels of generalization are predicted for people who are characterized by limited memory specificity. In a human contingency-learning procedure, participants learned the association between two pictures of female faces and a schematic drawing of a lightning bolt. Subsequently, six morphed pictures functioning as generalization stimuli (GSs) were introduced and conditioned responses to these GSs were measured. The results showed that memory specificity was significantly associated with the extent of generalization. Participants low in autobiographical memory specificity exhibited significantly stronger conditioned responses to GSs as compared to participants high in autobiographical memory specificity.

Using a conditioned suppression task, two experiments examined retrospective revaluation effects after serial compound training in a release from overshadowing design. In Experiment 1, serial X → A+ training produced suppression to target A, which was enhanced when preceded by feature X, whereas X by itself elicited no suppression. Subsequent A− presentations extinguished responding to A, but had no effect on either responding to X → A or X alone. However, the addition of A− trials did enhance the ability of feature X to elicit suppression to a novel target, B, suggesting retrospective revaluation of X’s properties. Experiment 2 showed that the enhanced transfer effect, observed in Experiment 1, was independent of the training history of the target (B− or Y → B+/B−). Together, these results suggest that feature X did not retrospectively acquire excitatory strength or occasion setting power, but rather a generalized ability to increase responding to any other cue.

Exposure-based interventions are core to the psychosocial treatment of anxiety disorders. Protocols utilizing these elements are associated with some of the highest effect sizes in the anxiety treatment literature (e.g., Hofmann & Smits, 2008). These interventions rely on the use of experience to aid the learning of safety in relation to the core fears underlying anxiety disorders; yet, the efficacy of these interventions may be limited by a number of contextual and procedural challenges. This chapter provides a review of studies of these procedures and parameters and provides a conceptual overview of a heuristic for guiding exposure interventions. Relative to this heuristic we attend to the stimulus properties, duration, spacing, gradation, and, particularly, context of exposure interventions.

Animal studies have shown that fear memories can change when recalled, a process referred to as reconsolidation. We found that oral administration of the beta-adrenergic receptor antagonist propranolol before memory reactivation in humans erased the behavioral expression of the fear memory 24 h later and prevented the return of fear. Disrupting the reconsolidation of fear memory opens up new avenues for providing a long-term cure for patients with emotional disorders.

Panic disorder is characterized by both specific, phased fear and generalized, chronic anxiety. Standard extinction procedures are efficient in reducing specific fear. However, methods based on human conditioning research - that are capable of reducing chronic anxiety have not yet been thoroughly investigated. This study evaluates a new way of reducing chronic anxiety by signaling aversive events (or by making them more predictable). Using an experimental approach with healthy participants, specific fear and chronic anxiety were operationalized in a within-subjects fear-potentiated startle paradigm by, respectively, conditioning to a cue by presenting predictable shocks and conditioning to a context induced by unpredictable shocks. The results clearly demonstrate that context conditioning is reduced when a discrete cue is added that predicts the onset of the aversive event. The data suggest that making unpredictable events, such as for example panic attacks, predictable, may reduce the generalized and sustained anxiety that often complicates exposure treatment.

Compared to blocking of conditioned excitation, which is one of the most investigated cue competition phenomena, blocking of conditioned inhibition has more or less been neglected in conditioning research. We conducted a human causal learning study and found evidence for blocking of conditioned inhibition. The results favor the view that inhibition is the symmetrical opposite of excitation, underlying the same general principles.

Lesion studies in animals have identified a critical role of the hippocampus in context fear conditioning. To extend these findings to human volunteers, we used functional magnetic resonance imaging to investigate neural responses associated with context fear conditioning in humans. Our novel conditioning paradigm consisted of aversive electrical shocks ( unconditioned stimulus) that were delivered either cue or context related. Differential evoked responses, related to the conditioned stimulus (CS), were found in the anterior cingulate cortex and the bilateral insular cortices, regions that have been implicated in anticipatory anxiety. In case of context conditioning, a similar pattern was observed during the presentation of the entire context. In line with previous conditioning studies, differential responses in the amygdala showed a time by stimulus interaction, suggesting rapid adaptation of CS-specific responses. More importantly, a similar differential decay of activation was observed during context conditioning in the hippocampus, in agreement with a role of the hippocampus in the acquisition phase of human context fear conditioning. ispartof: Journal of Neuroscience vol:28 issue:36 pages:9030-9036 ispartof: location:United States status: published

The present study was set up to investigate cued and contextual fear in situations of (un)predictability in a human fear conditioning paradigm. Forty-nine participants were presented with two different contexts (switching on and off the central lighting of the experimental room). In the predictable context, a visual cue (CS I) was systematically followed by an electrocutaneous stimulus (US). In the unpredictable context, CS2 was presented explicitly unpaired with the US. Dependent variables were online US-expectancy ratings and fear-potentiated startle. First, in both measures, the results showed significantly more fear elicited by CS I than by CS2. Second, larger startle amplitudes during the intertrial intervals demonstrated more contextual fear in the unpredictable than in the predictable context. Hence, these findings illustrate that unpredictability increases contextual fear. Moreover, the US-expectancy ratings during the intertrial intervals were also higher in the unpredictable than in the predictable context. This last finding suggests that a chronic expectation of the threatening US is responsible for sustained levels of anxiety in unpredictable situations. (C) 2007 Elsevier B.V. All rights reserved. ispartof: Biological Psychology vol:77 issue:1 pages:39-46 ispartof: location:Netherlands status: published

El objetivo de este estudio fue investigar el rol de la (im)predictabilidad en el paradigma de condicionamiento de miedo, al analizar las diferencias tanto en el condicionamiento específico (cue) como en el contextual. Por consiguiente, se manipuló la presentación del estímulo incondicionado (EI) utilizando dos condiciones: una presentación apareada del EI con el estímulo condicionado —EC en adelante— (predecible) y una presentación no apareada del EI (impredecible). Se manipuló el contexto utilizando la luz central del cuarto experimental: condiciones de oscuridad y claridad. Las variables independientes fueron la respuesta de conductancia de la piel y la medición de la respuesta de sobresalto. Los participantes fueron 65 alumnos de primer año de psicología. Los resultados muestran más condicionamiento contextual en el bloque no apareado (impredecible) comparado con el apareado, y condicionamiento específico en el bloque apareado (predecible).

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.

In a human fear conditioning experiment, 32 participants were trained in a differential conditioning procedure with geometrical shapes as CS+ and CS- (four presentations each), and an electric shock as US. Measures of conditioned responding were skin conductance response (SCR) and retrospective US-expectancy ratings. For half of the participants (Generalization Group, GG), the subsequent extinction phase consisted of four nonreinforced presentations of generalization stimuli (GS+ and GS-). Participants from the Extinction control Group received an equal amount of nonreinforced presentations of the CSs. Finally, all participants were tested with the original CSs. The results from both measures clearly show an increase in the size of the discrimination upon the stimulus change after extinction in the GG. Because this pattern is not observed in the Extinction control Group, extinction performance appears to be somehow restricted to the perceptual characteristics of the extinction stimulus. Interestingly, the size of the conditioned SCR discrimination in the GG is not influenced by the stimulus change after acquisition. This observation points to a differential impact of stimulus change after acquisition vs. extinction treatment. The findings are discussed from the theoretical perspective of renewal and the clinical perspective of Return of Fear.

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.