ИСТИНА

Natural learning generally involves complex stimuli consisting of several sensory modalities. Elemental learning theories suggest that each component of compound signal is encoded and associated separately. Configural theories predict that representation of the entire complex signal is formed and is associated with the second event. We developed a mouse model of fear conditioning to a compound tone-light cue or its separate components and used it to test these alternative theories. First, we studied the dynamics of memories for compound cue and its separate components and found that they mature over different time after conditioning. The same dissociation of these memories was observed in the extinction experiments. Second, we performed c-Fos imaging of cellular activity in frontal, prelimbic, cingular, retrosplenial, parietal, primary and secondary visual, primary and secondary auditory cortices after conditioning to the entire compound cue or to its components. We found that compound-cue and single-cue conditioning produced distinct patterns of cortical activation - prelimbic and frontal associative cortices were activated by conditioning to compound cue but not to single cues. Third, we showed that only retrieval of memory by the entire compound cue but not by single cues activated prelimbic, parietal, primary visual and mediolateral secondary visual cortices. Fourth, we performed in vivo two-photon imaging of retrieval-induced c-Fos expression in the parietal cortex of fos-EGFP transgenic mice and found that there are at least three neuronal populations with different response specificity to the compound signal and its components. Taken together, our data suggests that complex signals can establish both integral and elemental neuronal representations, these representations can be used separately in behavior and can have different dynamics in the long-term memory. Supported by RSF 23-78-00010.