K3-Flp;Gad2Cre DCZ Day 0 Only 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).

情境恐惧条件反射实验：小鼠在光照周期（早6点至晚6点）内开展为期3天的情境恐惧条件反射实验方案。在条件反射实验日（第0天）前，小鼠先接受3天的适应训练，每日1小时，4只小鼠为一组，置于中性适应环境中。为构建差异与相似兼具的情境环境，实验采用MedAssociates公司的实验箱与可更换插板，设置两个独立房间。情境A与B置于同一房间，情境C置于另一房间。每个情境均配置特定参数（地板、天花板、气味、声音、光照以及转运容器），详见扩展数据图3-1。其中情境B旨在与A高度相似，仅6项参数中的2项（地板与转运容器）发生了改变（扩展数据图3-1）。

所有实验日或仅如结果章节所述的特定实验日，在小鼠被放入行为实验箱（MedAssociates）前10分钟，通过腹腔注射（intraperitoneally，简称i.p.）给予生理盐水或1.0 mg/kg的DCZ（Ferrari、Ogbeide-Latario等，2022）。在习得训练阶段，小鼠先经历3分钟的基线期，随后接受4次足底电击（电流强度1 mA、时长2秒、电击间隔1分钟）（Zelikowsky、Bissiere等，2013）。末次电击结束1分钟后，习得训练结束，小鼠被转运回饲养笼。

24小时后即测试日1，小鼠按前述流程进行适应与给药。本数据集采用CC-BY-NC-ND 4.0国际许可协议发布。随后将小鼠暴露于情境A或"相似"情境B（采用平衡抵消设计），暴露时长为8分钟。实验结束后将小鼠返回动物房的饲养笼，至少静置5小时后，再更换至另一情境开展测试。24小时后，重复上述流程开展测试日2，此时将"相似"情境B替换为差异显著的"中性"情境C。

行为分析阶段，通过自动化近红外视频追踪设备及计算机软件（VideoFreeze，MedAssociates）生成组分文件以提取目标数据。对于第0天的条件反射实验，提取首次电击前3分钟的数据以分析基线冻结百分比与活动指数；同时提取每次电击前30秒的数据，以绘制恐惧习得曲线并分析冻结百分比。对于测试日1与测试日2，计算整个8分钟实验时段内的冻结时间百分比。

所有用于行为实验的小鼠均经过验证，确保病毒表达与靶向准确性。若小鼠未在CA3/门区表达病毒，或病毒在CA3/门区外的感染量高于区内，则将其排除于所有分析之外（扩展数据图3-1）。