Trace fear conditioning: a role for context?

Fear conditioning can be rapidly obtained over long trace intervals, but its specificity with respect to both time and stimulus is uncertain. Long-trace fear conditioning often parallels contextual conditioning, and it is sensitive to hippocampal lesions. These properties of trace conditioning are not directly addressed by timing models and multiple-time-scale models of conditioning. It is proposed that during early stages of conditioning, a joint representation of the context and the stimulus trace may underlie conditioned responses, and that discriminative processes allow the emergence of specific responses in a later stage.