Induction of conditioned avoidance via mental imagery.

There is a growing interest on how mental imagery may be involved in the onset and maintenance of anxiety-related disorders. Here, we used an experimental design to investigate whether a key symptom across anxiety-related disorders, namely avoidance, can be induced via mental imagery. Healthy participants first learned that one neutral stimulus (A) was associated with a mild electric shock and two other neutral stimuli (B and C) were not. They then learned to cancel the shock when A was presented, by pressing a button on a keyboard ('behavioral avoidance'). Next, they were asked to imagine that stimulus B was followed by the shock (i.e., without actual B or shock presentations; Experiment 1; N = 66) or they were shown B and asked to imagine the shock (i.e., without actual shock presentations; Experiment 2; N = 60). Finally, in the test phase, they were shown each of the three stimuli (without the shock) and given the opportunity to make the avoidance response. Results showed that participants tended to avoid B in the test phase in Experiment 1, even though it had never been presented with the shock but not in Experiment 2. We discuss how the findings may explain the acquisition of avoidance in the presentation of innocuousstimuli across anxiety-related disorders.

Side effects of induced lateral eye movements during aversive ideation.

BACKGROUND AND OBJECTIVES: Eye Movement Desensitization and Reprocessing (EMDR) is a treatment for posttraumatic stress disorder. It uses a dual-task approach, in which patients recall an aversive memory while making lateral eye movements. Research has shown that this 'eye movements' intervention reduces subjective memory vividness and emotionality. This study examined whether it also reduces memory accuracy on a visual discrimination task. METHODS: Participants (68 undergraduates) underwent an aversive conditioning phase, in which two pictures of male faces were followed by shock. Then they recalled one face with (experimental condition) and one without (control condition) making lateral eye movements. Finally, they completed a stimulus discrimination test with slightly different faces shortly after the intervention and one day later. RESULTS: Results showed that the eye movements intervention led to increased false-positive rates one day later. LIMITATIONS: Our intervention targeted newly formed memory rather than consolidated memory. CONCLUSIONS: The results inform theory about EMDR's mechanisms of change and suggest that the treatment may have side effects regarding memory accuracy.

Secondary extinction reduces reinstatement of threat expectancy and conditioned skin conductance responses in human fear conditioning.

BACKGROUND AND OBJECTIVES: Secondary extinction refers to the phenomenon that extinction of one conditioned stimulus (CS) results in the reduction of conditioned responses for other CSs conditioned with the same unconditioned stimulus (US). Previous research with rats has demonstrated that secondary extinction can interfere with the return of conditioned fear after a reinstatement manipulation. Here we investigated this phenomenon in two pre-registered studies in humans. METHOD: In both experiments, distinct CSs were paired with an electrical stimulation. Next, conditioned reactions to both CSs were extinguished and thereafter reinstated through the administration of three unsignaled electrical stimulations. Crucially, before participants continued with the reinstatement test, half of the participants received secondary extinction trials whereas the other half did not receive these trials. RESULTS: Our results indicate that secondary extinction reduced reinstatement of threat expectancies and skin conductance responses, but the effect on skin conductance was only found in the second experiment. LIMITATIONS: The studies were conducted in a laboratory setting with healthy students. Additional research will be required to determine the feasibility of applying secondary extinction in a (sub)clinical context. CONCLUSIONS: To our knowledge, this is the first demonstration of secondary extinction and its effect on reinstatement of conditioned fear in humans. We relate our findings to the earlier research with rats and discuss their relevance for exposure therapy.

Generalisation of threat expectancy increases with time.

Excessive fear generalisation is a feature characteristic of clinical anxiety and has been linked to its aetiology. Previous animal studies have shown that the mere passage of time increases fear generalisation and that brief exposure to training cues prior to long-term testing reverses this effect. The current study examined these phenomena in humans. Healthy participants learned the relationship between the presentation of a picture of a neutral male face and the delivery of a mild shock. One group was immediately tested with a novel picture of a somewhat different male face (generalisation test). Another group was tested one week later. A third group was also tested one week later and was additionally exposed to the training picture prior to testing. During picture presentations, shock-expectancy ratings were obtained as a measure of fear. Fear generalisation increased from the immediate test to the 1-week follow-up test. This result could not be attributed to level of neuroticism or a general increase in fear (incubation). Furthermore, the time-dependent increase in fear generalisation vanished following brief exposure to the training picture. Results indicate that human fear generalisation is a temporally dynamic process and that memory for stimulus details can be re-established following a reminder treatment.

Safety Behavior After Extinction Triggers a Return of Threat Expectancy.

Safety behavior is involved in the maintenance of anxiety disorders, presumably because it prevents the violation of negative expectancies. Recent research showed that safety behavior is resistant to fear extinction. This fear conditioning study investigated whether safety behavior after fear extinction triggers a return of fear in healthy participants. Participants learned that two stimuli (A and C) were followed by an aversive loud noise ("threat"), and one stimulus (B) was not. Participants then learned to use safety behavior that prevented the loud noise. Next, A and C were no longer followed by the loud noise, which typically led to extinction of threat expectancy. Safety behavior then became available again for C, but not for A and B. All participants used safety behavior on these C trials. In a final test phase, A, B, and C were presented once without the availability to use safety behavior. At each stimulus presentation, participants rated threat expectancy by indicating to what extent they expected that the loud noise would follow. Compared with the last extinction trial, threat expectancy increased for C in the test phase, whereas it did not increase for A and B. Hence, safety behavior after the extinction of classically conditioned fear caused a partial return of fear. The findings suggest that safety behavior may be involved in relapse after exposure-based therapy for anxiety disorders.

Beyond Extinction: Prolonged Conditioning and Repeated Threat Exposure Abolish Contextual Renewal of Fear-Potentiated Startle Discrimination but Leave Expectancy Ratings Intact.

Extinction treatments decrease fear via repeated exposures to the conditioned stimulus (CS) and are associated with a return of fear. Alternatively, fear can be reduced via reductions in the perceived intensity of the unconditioned stimulus (US), e.g., through repeated exposures to the US. Promisingly, the few available studies show that repeated US exposures outperform standard extinction. US exposure treatments can decrease fear via two routes: (1) by weakening the CS-US association (extinction-like mechanism), and/or (2) by weakening the subjective US aversiveness (habituation-like mechanism). The current study further investigated the conditions under which US exposure treatment may reduce renewal, by adding a group in which CS-US pairings continued following fear acquisition. During acquisition, participants learned that one of two visual stimuli (CS+/CS-) predicted the occurrence of an aversive electrocutaneous stimulus (US). Next, the background context changed and participants received one of three interventions: repeated CS exposures, (2) repeated US exposures, or (3) continued CS-US pairings. Following repeated CS exposures, test presentations of the CSs in the original conditioning context revealed intact CS+/CS- differentiation in the fear-potentiated startle reflex, while the differentiation was abolished in the other two groups. Differential US expectancy ratings, on the other hand, were intact in all groups. Skin conductance data were inconclusive because standard context renewal following CS exposures did not occur. Unexpectedly, there was no evidence for a habituation-like process having taken place during US exposures or continued CS-US pairings. The results provide further evidence that US exposures outperform the standard extinction treatment and show that effects are similar when US exposures are part of CS-US pairings.

Eye movement during recall reduces objective memory performance: An extended replication.

Eye Movement Desensitization and Reprocessing (EMDR) therapy for posttraumatic stress disorder involves making eye movements (EMs) during recall of a traumatic image. Experimental studies have shown that the dual task decreases self-reported memory vividness and emotionality. However valuable, these data are prone to demand effects and little can be inferred about the mechanism(s) underlying the observed effects. The current research aimed to fill this lacuna by providing two objective tests of memory performance. Experiment I involved a stimulus discrimination task. Findings were that EM during stimulus recall not only reduces self-reported memory vividness, but also slows down reaction time in a task that requires participants to discriminate the stimulus from perceptually similar stimuli. Experiment II involved a fear conditioning paradigm. It was shown that EM during recall of a threatening stimulus intensifies fearful responding to a perceptually similar yet non-threat-related stimulus, as evidenced by increases in danger expectancies and skin conductance responses. The latter result was not corroborated by startle EMG data. Together, the findings suggest that the EM manipulation renders stimulus attributes less accessible for future recall.

Countering fear renewal: changes in the UCS representation generalize across contexts.

After treatment of anxiety disorders, fear often returns. Analogue studies show that outside the extinction context the conditional stimulus (CS) activates the acquisition memory (CS predicts unconditional stimulus; UCS), rather than the extinction memory (CS does not predict UCS). Conditioning theory postulates that fear also diminishes after a reduction in the subjective cost of the UCS, which can occur in absence of any changes in the CS-UCS association. We hypothesized that fear reduction via "UCS deflation" generalizes across context. Healthy students underwent acquisition in context A with neutral CSs and 100dB white noise as UCS. One group received post-conditioning UCS exposure, in which UCS intensity decreased over time ("ABAdefl"). Another group received UCS presentations at equal intensity ("ABActrl"). Two groups did a filler task ("ABB"; "ABA"). Then, all groups underwent extinction in context B and were retested in context A (ABA-groups) or B (ABB-group). During each CS participants rated UCS expectancy and UCS cost. Results showed the typical increase in UCS expectancy following the context switch from extinction to test phase. In contrast, UCS deflation caused a reduction in cost ratings that was maintained after the context change. Findings suggest that UCS deflation techniques may reduce fear renewal.

Shaking that icky feeling: effects of extinction and counterconditioning on disgust-related evaluative learning.

Learned disgust appears to play an important role in certain anxiety disorders, and can be explained by the process of evaluative conditioning, in which an affective evaluative reaction evoked by an unconditional stimulus (US) is transferred to a conditional stimulus (CS). Much remains unknown about how disgust-related evaluative learning can be effectively eliminated. Study 1 of the present investigation examined the effects of extinction on reducing the negative evaluation of a CS that was acquired during disgust conditioning. Participants completed acquisition trials, with a disgusting picture as US and two neutral pictures as CS (CS+ was paired with the US; CS- was unpaired), followed by extinction trials ("CS only"; experimental condition) or a filler task (control condition). Extinction trials reduced acquired US expectancy to the CS+, but did not extinguish negative evaluations of the CS+. Study 2 examined the effects of counterconditioning on evaluative learned disgust. After disgust acquisition trials, counterconditioning trials followed in which the CS+ was paired with a pleasant US (experimental condition) or a filler task (control condition). Counterconditioning trials reduced acquired US expectancy to the CS+ and reduced evaluative conditioned disgust. Implications of the potential differential effects of extinction and counterconditioning on evaluative learning for exposure-based treatment of specific anxiety disorders are discussed.

How eye movements in EMDR work: changes in memory vividness and emotionality.

BACKGROUND AND OBJECTIVES: Eye movements (EM) during recall of an aversive memory is a treatment element unique to Eye Movement Desensitization and Reprocessing (EMDR). Experimental studies have shown that EM reduce memory vividness and/or emotionality shortly after the intervention. However, it is unclear whether the immediate effects of the intervention reflect actual changes in memory. The aim of this study was to test whether immediate reductions in memory vividness and emotionality persist at a 24 h follow up and whether the magnitude of these effects is related to the duration of the intervention. METHODS: Seventy-three undergraduates recalled two negative autobiographical memories, one with EM ("recall with EM") and one without ("recall only"). Half of participants recalled each memory for four periods of 24 s, the other half for eight periods of 24 s. Memory vividness/emotionality were self-rated at a pre-test, an immediate post-test, and a 24 h follow-up test. RESULTS: In both duration groups, recall with EM, but not recall only, caused an immediate decrease in memory vividness. There were no immediate reductions in memory emotionality. Furthermore, only the 'eight periods' group showed that recall with EM, but not recall only, caused a decrease in both memory emotionality and memory vividness from the pre-test to the follow-up. LIMITATIONS: Only self-report measures were used. CONCLUSIONS: The findings suggest that recall with EM causes 24-h changes in memory vividness/emotionality, which may explain part of the EMDR treatment effect, and these effects are related to intervention duration.

Impaired fear inhibition learning predicts the persistence of symptoms of posttraumatic stress disorder (PTSD).

Recent cross-sectional studies have shown that the inability to suppress fear under safe conditions is a key problem in people with posttraumatic stress disorder (PTSD). The current longitudinal study examined whether individual differences in fear inhibition predict the persistence of PTSD symptoms. Approximately 2 months after deployment to Afghanistan, 144 trauma-exposed Dutch soldiers were administered a conditional discrimination task (AX+/BX-). In this paradigm, A, B, and X are neutral stimuli. X combined with A is paired with a shock (AX+ trials); X combined with B is not (BX- trials). Fear inhibition was measured (AB trials). Startle electromyogram responses and shock expectancy ratings were recorded. PTSD symptoms were measured at 2 months and at 9 months after deployment. Results showed that greater startle responses during AB trials in individuals who discriminated between danger (AX+) and safety (BX-) during conditioning, predicted higher PTSD symptoms at 2 months and 9 months post-deployment. The predictive effect at 9 months remained significant after controlling for critical incidents during previous deployments and PTSD symptoms at 2 months. Responses to AX+ or BX- trials, or discrimination learning (AX+ minus BX-) did not predict PTSD symptoms. It is concluded that impaired fear inhibition learning seems to be involved in the persistence of PTSD symptoms.

Eye movements during recall of aversive memory decreases conditioned fear.

Cognitive-behavioral therapy for anxiety disorders typically involves exposure to the conditioned stimulus (CS). Despite its status as an effective and primary treatment, many patients do not show clinical improvement or relapse. Contemporary learning theory suggests that treatment may be optimized by adding techniques that aim at revaluating the aversive consequence (US) of the feared stimulus. This study tested whether US devaluation via a dual task--imagining the US while making eye movements--decreases conditioned fear. Following fear acquisition one group recalled the US while making eye movements (EM) and one group merely recalled the US (RO). Next, during a test phase, all participants were re-presented the CSs. Dual tasking, relative to the control condition, decreased memory vividness and emotionality. Moreover, only in the dual task condition reductions were observed in self-reported fear, US expectancy, and CS unpleasantness, but not in skin conductance responses. Findings provide the first evidence that the dual task decreases conditioned fear and suggest it may be a valuable addition to exposure therapy.

EMDR and mindfulness. Eye movements and attentional breathing tax working memory and reduce vividness and emotionality of aversive ideation.

BACKGROUND AND OBJECTIVES: Eye Movement Desensitization and Reprocessing (EMDR) and Mindfulness-Based Cognitive Therapy (MBCT) are effective in reducing the subjective impact of negative ideation. In both treatments, patients are encouraged to engage in a dual-task (eye movements (EM) in the case of EMDR and attentional breathing (AB) in the case of MBCT) while they experience negative thoughts or images. Working memory theory explains the effects of EM by suggesting that it taxes limited working memory resources, thus rendering the image less vivid and emotional. It was hypothesized that both AB and EM tax working memory and that both reduce vividness and emotionality of negative memories. METHODS: Working memory taxation by EM and AB was assessed in healthy volunteers by slowing down of reaction times. In a later session, participants retrieved negative memories during recall only, recall + EM and recall + AB (study 1). Under improved conditions the study was replicated (study 2). RESULTS: In both studies and to the same degree, attentional breathing and eye movements taxed working memory. Both interventions reduced emotionality of memory in study 1 but not in study 2 and reduced vividness in study 2 but not in study 1. LIMITATIONS: EMDR is more than EM and MBCT is more than AB. Memory effects were assessed by self reports. CONCLUSIONS: EMDR and MBCT may (partly) derive their beneficial effects from taxing working memory during recall of negative ideation.

Odors eliciting fear: a conditioning approach to Idiopathic Environmental Intolerances.

Patients suffering from Idiopathic Environmental Intolerances (IEI) report health symptoms, referable to multiple organ systems, which are triggered by harmless odors and therefore medically unexplainable. In line with previous research that predominantly points towards psychological explanations, the present study tests the hypothesis that IEI symptoms result from learning via classical conditioning of odors to fear. A differential conditioning paradigm was employed. Hedonically different odors were compared on ease of fear acquisition. Conditioned stimuli (CSs) were Dimethyl Sulfide (unpleasant) and peach (pleasant). The unconditioned stimulus (US) was an electrical shock. During acquisition one odor (CS+) was followed by shock, while the other odor (CS-) was not. Next, fear extinction was tested by presenting both CS+ and CS- without US. Electrodermal response, odor evaluation, and sniffing behavior were monitored. Results showed successful fear conditioning irrespective of hedonic character as evidenced by electrodermal response. Acquired fear did not extinguish. There was no evidence of evaluative conditioning taking place, as CS evaluation did not change during fear acquisition. Early avoidance of the CS+, as deduced from odor inhalation measures, was demonstrated, but did not sustain during the entire acquisition phase. This study suggests that a fear conditioning account of IEI is only partially satisfactory.

EMDR: eye movements superior to beeps in taxing working memory and reducing vividness of recollections.

Posttraumatic stress disorder (PTSD) is effectively treated with eye movement desensitization and reprocessing (EMDR) with patients making eye movements during recall of traumatic memories. Many therapists have replaced eye movements with bilateral beeps, but there are no data on the effects of beeps. Experimental studies suggest that eye movements may be beneficial because they tax working memory, especially the central executive component, but the presence/degree of taxation has not been assessed directly. Using discrimination Reaction Time (RT) tasks, we found that eye movements slow down RTs to auditive cues (experiment I), but binaural beeps do not slow down RTs to visual cues (experiment II). In an arguably more sensitive "Random Interval Repetition" task using tactile stimulation, working memory taxation of beeps and eye movements were directly compared. RTs slowed down during beeps, but the effects were much stronger for eye movements (experiment III). The same pattern was observed in a memory experiment with healthy volunteers (experiment IV): vividness of negative memories was reduced after both beeps and eye movements, but effects were larger for eye movements. Findings support a working memory account of EMDR and suggest that effects of beeps on negative memories are inferior to those of eye movements.