engleski

Timing of extinction relative to acquisition: A parametric analysis of fear extinction in humans

Fear extinction is a reduction in conditioned fear responses following repeated exposure to the feared cue in the absence of any aversive event. Exposure treatments for anxiety disorders such as posttraumatic stress disorder can be conceptualized as clinical analogues of extinction. Extinguished fear often reappears over time after extinction, an occurrence known as spontaneous recovery. Recent animal studies from our group suggest that spontaneous recovery can be abolished if extinction occurs within minutes of fear acquisition. To date, the limited number of human studies of fear extinction have shown that short interval extinction does not prevent the return of conditioned fear. For this reason, we performed an in-depth parametric analysis of human fear extinction using fear- potentiated startle measures. We employed both single cue and differential conditioning paradigms in which participants were fear conditioned by repeatedly pairing a colored light (conditioned stimulus) and an aversive airblast to the throat (unconditioned stimulus). Participants were then extinguished either 10 min (Immediate) or 72 hr (Delayed) later. Testing for spontaneous recovery occurred 96 hr after acquisition in both groups. In the single cue paradigm, subjects in the Immediate and Delayed groups exhibited differences in context conditioning but not fear conditioning. In the differential conditioning paradigm, there were no differences in context

time of exinction ; acquisition ; feaf exctinction

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