No Sex Difference in Contextual Control over the Expression of Latent Inhibition and Extinction in Pavlovian Fear Conditioning in Rats

Abstract

Three experiments with Wistar rats searched for a sex difference in contextual control over the expression of latent inhibition and extinction. Experiment 1 used a latent inhibition procedure; Experiments 2 and 3 employed an extinction preparation. All experiments used a shock as the unconditioned stimulus, a tone as the conditioned stimulus, and suppression of food magazine visits as the measure of conditioned responding to the tone. Each experiment revealed a reliable context effect on conditioned responding to the tone; after conditioning in a separate context, conditioned responding in the former latent inhibition or extinction context was attenuated relative to conditioned responding in a control context. There was no sex difference in the magnitude of this effect. These results are discussed in the framework of sex differences in the hippocampus and of the putative role of this structure in various instances of contextual learning.