Contextual Fear after Signalled versus Unsignalled Shocks: Effect of Extent of Prior Experience with Context and Signal

• Published in: The Quarterly journal of experimental psychology. B, Comparative and physiological psychology Vol. 49; no. 2; pp. 148 - 173
• Main Author: Maes, J.H. Roald
• Format: Journal Article
• Language: English
• Published: London, England Taylor & Francis Group 01.05.1996; SAGE Publications
• ISSN: 0272-4995; 1464-1321
• DOI: 10.1080/713932622

In the first two experiments, rats were differentially familiarized with a discrete stimulus and/ or a context prior to receiving either shocks signalled by that stimulus or unsignalled shocks in that context. As indexed by freezing, in none of the pre-exposure conditions did the signalled-shock rats consistently acquire less contextual fear than the unsignalled-shock animals. Both pre-exposure to the stimulus and relatively short pre-exposure to the future conditioning context resulted in more contextual fear in the signalled-shock than in the unsignalled-shock subjects. In a third experiment, freezing in the target conditioning context was especially enhanced in rats that had been familiarized with a stimulus, conditioned with the stimulus as a signal for shock, and subsequently further conditioned to the stimulus in a different, non-target context. The level of freezing to the stimulus in a neutral test context was positively related to the level of freezing in the target conditioning context in all experiments. These results were discussed in terms of context-shock, stimulus-shock, and context-stimulus associations.