As previously reported, some mice discriminated appropriately between CS+ and CS− based on their freezing behavior (referred to as discriminators, defined by at least 10% more freezing to the CS+ than the CS−; cutoff determined as in Likhtik et al., 2014), while other mice displayed generalized freezing to both stimuli (generalizers, <10% difference between CS+ and CS− freezing rates). During the CS+, freezing behavior was equivalent between discriminators and generalizers (Figure S1D); thus, we analyzed BLA LFP activity across all animals (n=23) during CS+ presentations on Day 4 to evaluate fear-related activity. In contrast, the explicitly unpaired CS− reflects a potentially aversive stimulus that was successfully associated with safety in discriminators (n=14), allowing us to subsequently evaluate safety-related physiological changes.
