K3-Flp;Gad2-Cre Contextual Fear Conditioning Data

Contextual Fear Conditioning: Mice underwent a 3-day contextual fear conditioning protocolduring their light cycle (6am-6pm). Mice were habituated for 3 days prior to conditioning day (Day 0) for 1 hour in squads of 4 to a neutral habituation room. To create distinct and similar contextual environments, chambers and interchangeable inserts from MedAssociates were used in two rooms. Contexts A and B were presented in the same room, and context C was presented in a different room. Each context was assigned a specific set of features (floor, roof, scent, sound, light, and transport vessels) as described in Extended data Figure 3-1. Context B is meant to closely resemble A, thus only 2 of 6 features (floor and transport) were altered (Extended data Figure 3-1). Mice were injected intraperitoneally (i.p.) with saline or 1.0 mg/kg DCZ (Ferrari, Ogbeide-Latario et al. 2022) 10 minutes prior to being placed into behavior boxes (MedAssociates) on all days or only on a specific day as described in the results section. During acquisition, mice received 4 shocks (1 mA, 2-second duration, 1-minute inter-shock interval), delivered after an initial 3-minute baseline period (Zelikowsky, Bissiere et al. 2013). One minute after the final shock, acquisition ended, and mice were transported back to their home cage. 24 hours later, on test day 1, mice were habituated and injected as described earlier. Conditioned available under aCC-BY-NC-ND 4.0 International license. Mice were exposed to context A for 8 minutes or to the “similar” context B (counter balanced). Mice were returned to their home cage in the vivarium for a minimum of 5 hours before being tested in the alternative context. Twenty-four hours later, this process was repeated for test day 2, with the distinct, “neutral” context C replacing the “similar” context B. To analyze behavior, component files were made to extract the desired data using automated near-infrared video tracking equipment and computer software (VideoFreeze, MedAssociates). For conditioning day 0, the 3-minutes prior to the first shock were extracted to analyze baseline percent component freezing and motion index. The 30 seconds preceding each shock were also extracted to analyze the percent component freezing for fear acquisition curves. For test days 1 and 2, the percent time freezing was calculated for the entire 8-minute session. All mice used for behavior were verified for correct virus expression and targeting. Mice were excluded from all analyses if they did not express virus in the CA3/hilus region or had more infection outside the CA3/hilus region than inside (Extended Data Figure 3-1).