Integrating Optogenetics and Fear Conditioning

Data shown are representative results from 4 OMP-ChIEF mice and 4 wild type mice (all males, 6-7 weeks old). Experimental animals were prepared by the surgical implantation of the optical fiber in the mouse olfactory bulb. A behavioral training commenced using a modified 'two-arms maze,' derived from the 'Y' maze design. Two arms of the maze are marked as light zone and safe zone. During training, light stimulation paired with mild foot shocks was applied as the mice fully entered into the light zone. The Safe zone remained accessible to the mice to avoid the foot shocks. The light stimulation involved ten 50 ms pulses with 150 ms intervals, triggered externally by a Master-8 timer.<b>Light zone aversion assessment task</b>To ensure unbiased testing conditions, the electric grid shock floor was removed from the "two-arms maze," eliminating foot shock exposure during the testing sessions. Mouse activity within the maze was evaluated in blocks of three trials, each lasting 15 minutes. Movement within the "two-arms maze" was tracked using Any-maze video tracking software (Stoelting, IL, USA) to calculate time spent in each arm. Additionally, heatmaps were generated for every trial, visually displaying the duration spent by mice in distinct areas of the arena. Color ranges within the heatmap represented varying durations, with blue indicating the shortest and red indicating the longest time spent in specific regions.<br>

本次展示的数据为4只OMP-ChIEF小鼠与4只野生型（wild type）小鼠的代表性实验结果，所有小鼠均为6~7周龄雄性。实验动物通过外科手术在小鼠嗅球植入光纤制备而成。实验采用改良自Y型迷宫的"双臂迷宫"开展行为训练，迷宫的两个臂分别标记为光照区（light zone）与安全区（safe zone）。训练阶段中，当小鼠完全进入光照区时，将施加伴随轻微足底电击的光刺激；小鼠可自由进入安全区以规避足底电击。该光刺激由Master-8定时器外部触发，包含10个50ms脉冲，脉冲间隔为150ms。
**光照区厌恶评估任务**
为保证测试条件无偏，实验移除了"双臂迷宫"的电网电击底板，消除了测试阶段的足底电击暴露。迷宫中小鼠的活动以3个试次为一组进行评估，每组试次时长15分钟。采用Any-maze视频追踪软件（美国伊利诺伊州Stoelting公司）追踪"双臂迷宫"内的小鼠活动，以计算其在各臂的停留时间。此外，为每个试次生成热图，直观展示小鼠在迷宫区域内不同位置的停留时长。热图的色阶代表不同的停留时长，蓝色表示对应区域停留时间最短，红色则表示停留时间最长。