Modeling Associative Fear Learning with Multisensory Cues in Mice

Animals in natural environments encounter multiple simultaneous cues, but standard fear conditioning paradigms typically use only one simple cue. We developed a complex cued fear conditioning (CCFC) task in mice with a combined auditory-visual conditioned stimulus to better represent natural conditions. We aimed to determine how multimodal cues affect fear memory formation and to identify optimal training parameters for robust long-term memory. We first selected contexts that did not elicit anxiety manifested in freezing. After that, we chose parameters for the cued fear conditioning task – a clear tone (9 kHz, 80 dB), a blinking light (5Hz), and a 0.75mA footshock. The freezing percentage to the stimuli was measured one week later to assess memory retention. Memory for each component was also tested separately after complex-cue training. Mice trained with a complex conditioned stimulus (light + tone) exhibited significant freezing responses to each component when tested individually, irrespective of the order of presentation, indicating robust long-term memory formation for both elements. The use of non-anxiogenic testing contexts and precisely synchronized multimodal cues in this Complex Cued Fear Conditioning (CCFC) paradigm facilitates the induction of strong and enduring associative fear memories. This approach enhances the ecological validity of fear learning models by more closely approximating natural threat cues. The observed retention of memory for individual components of the complex stimulus underscores the utility of the CCFC paradigm for investigating the encoding and retrieval of multimodal fear memories.