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RF Westbrook"Extinction of Pavlovian conditioned fear responses in rats."

Abstract :


A series of experiment studied spontaneous recovery of fear responses (freezing) to an extinguished conditioned stimulus (CS) in rats.
The initial experiments demonstrated that: a remotely extinguished CS elicited more freezing on a common extinction test than a recently extinguished one; this difference survived retraining; and the CS undergoing recovery suffered greater loss than the one lacking recovery. Additional experiments showed that an excitor extinguished in compound with a CS undergoing recovery suffered greater loss than an excitor extinguished in compound with a CS lacking recovery. Extinction of a compound composed of a CS undergoing recovery and one lacking recovery produced greater loss to the CS undergoing recovery. The results show that spontaneous recovery deepens extinction. They suggest that response loss is regulated by common and individual error terms.

Selected publications

Thein, T., Westbrook, R. F., & Harris, J. A. (in press). How the associative strengths of stimuli combine in compound: summation and overshadowing. Journal of Experimental Psychology: Animal Behavior Processes.
Li, S. H., & Westbrook, R. F. (in press). Massed extinction trials produce better short-term but worse long-term loss of context conditioned fear responses than spaced trials. Journal of Experimental Psychology: Animal Behavior Processes.

Alain Marchand