Interfering with emotional processing resources upon associative threat memory reactivation does not affect memory retention.

Ample evidence suggests that memories enter a labile state upon retrieval, requiring reconsolidation processes in order to be retained. During this period of instability, various interventions can be applied to modify problematic memories. A novel behavioral intervention was designed, aimed at disrupting amygdala-based cognitive processing following the retrieval of a conditioned threat memory, in order to prevent its reconsolidation. We fear-conditioned participants on day 1, and reactivated their memory on day 2. Following reactivation, the reactivation plus emotional working memory task (R + EWMT) group completed an EWMT, while the reactivation only (RO) group served as a no-task control. On day 3, all participants were tested for memory retention, followed by a test for sensitivity to reinstatement. We observed successful acquisition and reactivation in fear-potentiated startle responding, skin conductance responding and US expectancies in both groups. Differential fear responding was fully preserved in the R + EWMT group relative to the RO group at the beginning of retention testing, and both groups were comparably sensitive to reinstatement. Thus, we failed to obtain any evidence that the execution of an EWMT after threat memory reactivation impairs reconsolidation. Further research is indicated to clarify whether threat memory reconsolidation can be disrupted by taxing relevant WM resources.

Acquisition and extinction of operant pain-related avoidance behavior using a 3 degrees-of-freedom robotic arm.

Ample empirical evidence endorses the role of associative learning in pain-related fear acquisition. Nevertheless, research typically focused on self-reported and psychophysiological measures of fear. Avoidance, which is overt behavior preventing the occurrence of an aversive (painful) stimulus, has been largely neglected so far. Therefore, we aimed to fill this gap and developed an operant conditioning procedure for pain-related avoidance behavior. Participants moved their arm to a target location using the HapticMaster (FCS Robotics; Moog Inc, East Aurora, New York), a 3 degrees-of-freedom, force-controlled robotic arm. Three movement trajectories led to the target location. If participants in the Experimental Group took the shortest/easiest trajectory, they always received a painful stimulus (T1 = 100% reinforcement; no resistance). If they deviated from this trajectory, the painful stimulus could be partly or totally prevented (T2 = 50% reinforcement; T3 = 0% reinforcement), but more effort was needed (T2 = moderate resistance and deviation; T3 = strongest resistance and largest deviation). The Yoked Group received the same reinforcement schedule irrespective of their own behavior. During the subsequent extinction phase, no painful stimuli were delivered. Self-reported pain-expectancy and pain-related fear were assessed, and avoidance behavior was operationalized as the maximal distance from the shortest trajectory. During acquisition, the Experimental Group reported more pain-related fear and pain-expectancy to T1 vs T2 vs T3 and deviated more from the shortest trajectory than the Yoked Group. During subsequent extinction, avoidance behavior, self-reported fear, and pain-expectancy decreased significantly, but conditioned differences persisted despite the absence of painful stimuli. To conclude, this operant learning task might provide a valid paradigm to study pain-related avoidance behavior in future studies.

Preexposure to (un)predictable shock modulates discriminative fear learning between cue and context: an investigation of the interaction between fear and anxiety.

It has been suggested that prior experiences with unpredictable/uncontrollable stressors facilitate subsequent fear learning and the development of anxiety disorders. However, animal research documents that preexposure to unpredictable stressors (USs) impede later fear conditioning with that US. These differential predictions were tested in a human experimental model of clinical anxiety. One (US-only) group was preexposed to unpredictable shocks, a second (Unpaired) group received explicitly unpaired presentations of a neutral shape and the shock, and a third (Paired) group received paired shape-shock presentations. Next, all groups received training with a novel shape, using the same shock (50% reinforcement). Fear responding was assessed through startle modulation and online shock-expectancy ratings. Results showed retarded fear learning in the unpredictable groups compared to the predictable group. We argue that prior experiences of unpredictability may still contribute to the development of clinical anxiety, by impeding adaptive fear learning and perpetuating the perception of unpredictability/uncontrollability.

Dissociations between ABA-, ABC-, and AAB-renewal of Pavlovian modulation in human sequential feature positive discrimination learning.

Using a conditioned suppression preparation, we investigated extinction and aba-, abc-, and aab-renewal of Pavlovian modulation in human sequential Feature Positive (FP) discrimination learning, X → A+/A-. Extinction treatment was administered in the acquisition context a (aaa- and aab-groups) or in a new context b (aba- and abc-groups) and comprised X → A- extinction trials. Discriminative X → A/A responding was lost in all groups when tested in the extinction context. In the aba-group, the discriminative X → A/A responding totally recovered when retested in the acquisition context a. For the aaa-, the aab-, and the abc-group, discriminative X → A/A responding did not reappear when tested for renewal in, respectively, contexts a, b, and c. The demonstration of aba-renewal of extinguished modulation, but not abc- and aab-renewal, suggests that extinction in a context different from the acquisition context and a return to the original acquisition context might both be critical for renewal of Pavlovian modulation in human FP-discrimination learning.

Exposure to the context and removing the unpredictability of the US: two methods to reduce contextual anxiety compared.

Chronic anxiety may differ from cued fear and hence require other treatment strategies. In a human fear conditioning paradigm, chronic anxiety to the experimental context was experimentally induced by presenting unpredictable shocks. Two methods to reduce chronic anxiety were tested and compared. First, in parallel with the standard extinction procedure, participants were exposed to the anxiety-eliciting context in the absence of shocks (context-exposure group). Second, an alternative procedure was tested in which the previously unpredictable shocks were now signaled by a specific cue (signaled group). A control group continued to receive unsignaled shocks. Results indicated that chronic contextual anxiety, as measured by fear-potentiated startle and US-expectancy ratings, was equally reduced in the context-exposure group as in the signaled group compared with the control group. When applied to the treatment of, for example, panic disorder, these findings support the idea that exposure to the context in which the unpredictable panic attacks occurred and making unpredictable panic attacks predictable, are both valuable methods in order to reduce chronic anxiety.

Reducing chronic anxiety by making the threatening event predictable: an experimental approach.

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.