Refine
Document Type
- Article (4)
Language
- English (4)
Has Fulltext
- yes (4)
Is part of the Bibliography
- no (4)
Keywords
- - (3)
- anxiety disorders (1)
- attentive immobility (freezing) (1)
- expectancy violation (1)
- exposure therapy (1)
- extinction (1)
- fear bradycardia (1)
- fear conditioning (1)
- mechanisms of change (1)
- prediction error (1)
Institute
Publisher
- S. Karger AG (1)
- SAGE Publications (1)
- Springer Nature (1)
Extinction learning is suggested to be a central mechanism during exposure-based cognitive behavioralpsychotherapy. A positive association between the patients’pretreatment extinction learning performance andtreatment outcome would corroborate the hypothesis. Indeed, there isfirst correlational evidence between reducedextinction learning and therapy efficacy. However, the results of these association studies may be hampered byextinction-training protocols that do not match treatment procedures. Therefore, we developed an extinction-trainingprotocol highly tailored to the procedure of exposure therapy and tested it in two samples of 46 subjects in total. Byusing instructed fear acquisition training, including a consolidation period overnight, we wanted to ensure that theconditioned fear response was well established prior to extinction training, which is the case in patients with anxietydisorders prior to treatment. Moreover, the extinction learning process was analyzed on multiple response levels,comprising unconditioned stimulus (US) expectancy ratings, autonomic responses, defensive brain stem reflexes, andneural activation using functional magnetic resonance imaging. Using this protocol, we found robust fearconditioning and slow-speed extinction learning. We also observed within-group heterogeneity in extinction learning,albeit a stable fear response at the beginning of the extinction training. Finally, we found discordance betweendifferent response systems, suggesting that multiple processes are involved in extinction learning. The paradigmpresented here might help to ameliorate the association between extinction learning performance assessed in thelaboratory and therapy outcomes and thus facilitate translational science in anxiety disorders
Abstract
During fear conditioning, a cue (CS) signals an inevitable distal threat (US) and evokes a conditioned response that can be described as attentive immobility (freezing). The organism remains motionless and monitors the source of danger while startle responses are potentiated, indicating a state of defensive hypervigilance. Although in animals vagally mediated fear bradycardia is also reliably observed under such circumstances, results are mixed in human fear conditioning. Using a single‐cue fear conditioning and extinction protocol, we tested cardiac reactivity and startle potentiation indexing low‐level defensive strategies in a fear‐conditioned (n = 40; paired presentations of CS and US) compared with a non‐conditioned control group (n = 40; unpaired presentations of CS and US). Additionally, we assessed shock expectancy ratings on a trial‐by‐trial basis indexing declarative knowledge of the previous contingencies. Half of each group underwent extinction under sham or active transcutaneous vagus nerve stimulation (tVNS), serving as additional proof of concept. We found stronger cardiac deceleration during CS presentation in the fear learning relative to the control group. This learned fear bradycardia was positively correlated with conditioned startle potentiation but not with declarative knowledge of CS‐US contingencies. TVNS abolished differences in heart rate changes between both groups and removed the significant correlation between late cardiac deceleration and startle potentiation in the fear learning group. Results suggest, fear‐conditioned cues evoke attentive immobility in humans, characterized by cardiac deceleration and startle potentiation. Such defensive response pattern is elicited by cues predicting inevitable distal threat and resembles conditioned fear responses observed in rodents.
Individual responses to behavioral treatment of anxiety disorders vary considerably, which requires a better understanding of underlying processes. In this study, we examined the violation and change of threat beliefs during exposure. From 8,484 standardized exposure records of 605 patients with different anxiety disorders, learning indicators were derived: expectancy violation as mismatch between threat expectancy before exposure and threat occurrence, expectancy change as difference between original and adjusted expectancy after exposure, and prediction-error learning rate as extent to which expectancy violation transferred into change. Throughout sessions, high threat expectancy but low occurrence and adjusted expectancy indicated successful violation and change of threat beliefs by exposure. Expectancy violation, change, and learning rate substantially varied between patients. Not expectancy violation itself, but higher learning rate and expectancy change predicted better treatment outcome. Successful exposure thus requires expectancy violation to induce actual expectancy change, supporting learning from prediction error as transdiagnostic mechanism underlying successful exposure therapy.