Attentional Control and Fear Extinction in Subclinical Fear: An Exploratory Study

Conceptual-level disgust conditioning in contamination-based obsessive-compulsive disorder

Pavlovian fear conditioning and extinction represent learning mechanisms underlying exposure-based interventions. While increasing evidence indicates a pivotal role of disgust in the development of contamination-based obsessive-compulsive disorder (C-OCD), dysregulations in conditioned disgust acquisition and maintenance, in particular driven by higher-order conceptual processes, have not been examined. Here, we address this gap by exposing individuals with high (HCC, n = 41) or low (LCC, n = 41) contamination concern to a conceptual-level disgust conditioning and extinction paradigm. Conditioned stimuli (CS+) were images from one conceptual category partially reinforced by unconditioned disgust-eliciting stimuli (US), while images from another category served as non-reinforced conditioned stimuli (CS-). Skin conductance responses (SCRs), US expectancy and CS valence ratings served as primary outcomes to quantify conditioned disgust responses. Relative to LCC, HCC individuals exhibited increased US expectancy and CS+ disgust experience, but comparable SCR levels following disgust acquisition. Despite a decrease in conditioned responses from the acquisition phase to the extinction phase, both groups did not fully extinguish the learned disgust. Importantly, the extinction resilience of acquired disgust was more pronounced in HCC individuals. Together, our findings suggest that individuals with high self-reported contamination concern exhibit increased disgust acquisition and resistance to extinction. The findings provide preliminary evidence on how dysregulated disgust learning mechanism across semantically related concepts may contribute to C-OCD.

Deleting "fear" from "fear extinction": Estimating the individual extinction rate via non-aversive conditioning

Individual differences in extinction learning have attracted ample attention of researchers and are under investigation as a marker for the onset of anxiety disorders and treatment response. Unfortunately, the common paradigm for obtaining the extinction rate, which entails aversive stimulus pairings, is subject to practical limitations. Therefore, the present study assessed whether the use of an aversive stimulus is actually needed to get a good estimate of the extinction rate. A total of 161 undergraduate students completed a conditioning task with both an aversive and a non-aversive stimulus. Using latent class growth analysis (LCGA), distinct trajectories, representing normal and stunted extinction learning, were identified for both these stimulus types. Participants' membership in these classes largely overlapped for aversive and non-aversive stimulus pairings and respective extinction indices were significantly correlated. Thereby, findings suggest that the use of a non-aversive stimulus could suffice for successfully capturing individual differences in extinction learning. However, future studies are needed to confirm that conditioning with a non-aversive stimulus may serve to predict clinically relevant outcomes.

Fear Extinction Retention: Is It What We Think It Is?

There has been an explosion of research on fear extinction in humans in the past 2 decades. This has not only generated major insights, but also brought a new goal into focus: how to maintain extinction memory over time (i.e., extinction retention). We argue that there are still important conceptual and procedural challenges in human fear extinction research that hamper advancement in the field. We use extinction retention and the extinction retention index to exemplarily illustrate these challenges. Our systematic literature search identified 16 different operationalizations of the extinction retention index. Correlation coefficients among these different operationalizations as well as among measures of fear/anxiety show a wide range of variability in four independent datasets, with similar findings across datasets. Our results suggest that there is an urgent need for standardization in the field. We discuss the conceptual and empirical implications of these results and provide specific recommendations for future work.