| Abstract: | Investigated whether fear extinction conducted under the influence of a benzodiazepine transfers to the undrugged state in rats. Fear was conditioned by pairing an experimental chamber with footshock and was assessed by observing freezing, a characteristic response of the rat to stimuli associated with shock. In Exp 1, both chlordiazepoxide (librium) and diazepam (valium) interfered wih extinction in a dose-dependent manner as indicated by freezing during an undrugged test. Further results with chlordiazepoxide suggested that the effect depended on the drug's specific combination with extinction and that it occurred even though the extinction procedure otherwise eliminated fear completely (Exp 2). Repeated preexposure to the drug, and the development of partial tolerance to its sedative effects, did not weaken the interference effect (Exp 3). Other evidence suggested that the drug signaled or retrieved extinction instead of disrupting learning or consolidation (Exp 4). The results are consistent with research suggesting that extinguished fear can be "renewed" if the exteroceptive contextual stimuli are changed after extinction. Extinction combined with either unique exteroceptive or interoceptive cues may be specific to its context. (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
