Differential effects of immediate vs. delayed extinction training and the variation of the time interval between extinction training and test on the return of fear: neural and peripheral-physiological correlates
Final Report Abstract
Within clinical psychology, extinction processes are central models for the maintenance and treatment of anxiety disorders and have increasingly become the focus of research in recent years. Within affective learning processes, a distinction is often made between different phases: (1) fear acquisition, (2) extinction training and (3) retention test (also called extinction test). An important question in the context of extinction relates to the significance of the time at which extinction training is carried out. In humans, extinction training is often carried out either immediately (i.e. directly after fear acquisition) or with a delay (e.g. 24 hours later). To date, only a few studies have compared the two time points (immediate vs. delayed). In these studies, delayed extinction training was found to lead to higher conditioned fear responses during the retention test. These results support previous memory models that assume that memory traces are more fragile (and thus more easily changed) immediately after immediate encoding, while memory traces are more difficult to change after delayed extinction training due to deeper consolidation. The project described here investigated the core question of whether an experimental variation in the timing of extinction training (immediate vs. delayed) is associated with altered neuronal processing and differential responsivity with regard to the recurrence of conditioned fear responses. Furthermore, various factors that may be associated with fear learning or extinction were investigated. To answer the core question, a multi-day differential fear extinction paradigm was conducted with a total of four groups. The four groups differed in the time interval between fear acquisition and extinction training (immediate vs. delayed) and the time interval between extinction training and retention test (1 day vs. 7 days). The immediate extinction of the conditioned stimulus led to a greater retention of fear at the beginning of extinction training, as indicated by an increase in the skin conductance response. A return of fear was observed in both extinction groups, with a trend toward a greater return of fear in immediate extinction. The return of fear was, on average, higher in groups that underwent an early test. The neuroimaging results demonstrate the successful acquisition and retention of fear across different groups, as well as the activation of the left nucleus accumbens during extinction training. Interestingly, the delayed extinction group exhibited a more pronounced bilateral nucleus accumbens activation during the test.
Publications
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Neural correlates of immediate versus delayed extinction when simultaneously varying the time of the test in humans. Cerebral Cortex, 33(15), 9325-9338.
Kampa, Miriam; Hermann, Andrea; Stark, Rudolf & Klucken, Tim
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The impact of past childhood adversity and recent life events on neural responses during fear conditioning. Journal of Neuroimaging, 34(2), 217-223.
Kampa, Miriam; Stark, Rudolf & Klucken, Tim
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The impact of extinction timing on pre-extinction arousal and subsequent return of fear. Learning & Memory, 31(4), a053902.
Kampa, Miriam; Stark, Rudolf & Klucken, Tim
