Individual expression of conditioned safety but not of conditioned relief is correlated with contextual fear.

Stimuli that are either presented directly after or explicitly unpaired to an aversive event can be associated with the relief or absence of the aversive event. Such stimuli then become conditioned stimuli (CS) for relief or safety, respectively, and are able to induce appetitive-like behavioral responses, e.g. startle attenuation. Of note, the aversive event is not only associated with the stimuli but also with the context in which the aversive event occurs. However, it is poorly understood whether this context affects the expression of conditioned relief or safety. Using laboratory rats, we demonstrated that the individual effects of a safety CS, but not of a relief CS, is strongly correlated with the fear-inducing properties of the experimental context. This suggest that the expression of conditioned safety is more sensitive to contextual fear than conditioned relief. Our findings are in line with the idea that a safety CS works as a conditioned inhibitor (here: of contextual fear). As safety learning is affected in anxiety disorders, the context-sensitivity of safety CS could be considered in the therapy of anxiety disorder patients.