[Long-Term Contextual Memory in Mice: Persistence and Associability with Reinforcement].

Abstract

Animals can associate memory of a context with unconditioned stimuli even if there is a long time in- terval between acquisition of contextual memory and its subsequent reinforcement. This phenomenon of context preexposure effect was first described and investigated in rats. Here we studied the possibility of associating previously acquired memory about a context with unconditioned stimulus (immediate shock) in mice. We showed that fear memory in this model was specific for the previously explored context but not for the context of immediate shock. Associative learning was possible when acquisition of contextual memory and presentation unconditioned stimulus (immediate shock) were spaced in the range of 30 min-30 days interval. Resulting memory was stable and persisted for at least 30 days. Our results open new avenues for studies of neuronal mechanisms of associative memory using transgenic re- porter mice.