Hippocampal place cell remapping occurs with memory storage of aversive experiences

Aversive stimuli can cause hippocampal place cells to remap their firing fields, but it is not known whether remapping plays a role in storing memories of aversive experiences. Here we addressed this question by performing in-vivo calcium imaging of CA1 place cells in freely behaving rats (n=14). Rats were first trained to prefer a short path over a long path for obtaining food reward, then trained to avoid the short path by delivering a mild footshock. Remapping was assessed by comparing place cell population vector similarity before acquisition versus after extinction of avoidance. Some rats received shock after systemic injections of the amnestic drug scopolamine at a dose (1 mg/kg) that impaired avoidance learning but spared spatial tuning and shock-evoked responses of CA1 neurons. Place cells remapped significantly more following remembered than forgotten shocks (drug-free versus scopolamine conditions); shock-induced remapping did not cause place fields to migrate toward or away f..., MiniLFOV calcium imaging system
To record calcium activity during unrestrained behavior, we utilized a large field-of-view version of the Miniscope imaging system, “MiniLFOV” (Guo et al. 2023). This open-source epifluorescence imaging camera weighs 13.9 g with a 3.6 x 2.3 mm field of view while maintaining a 2.5 um resolution at the center of view and 4.4 um at the periphery. The MiniLFOV can record at 22 Hz, has a 5MP CMOS imaging sensor, an electrowetting lens for digitally setting the focal plane, and a modular lens configuration to enable a longer working distance (either 1.8 mm, used here, or 3.5 mm). The system is 20x more sensitive than previous v3 Miniscopes, and twice as sensitive as current v4 Miniscopes. Power, communication, and image data are packed into a flexible 50 Ω coaxial cable (CW2040-3650SR, Cooner Wire) using power-over-coax filtering and a serializer/deserializer pair for bi-directional control communication with I2C protocol and uni-directional high bandwidth dat..., MATLAB 2016 (or later) or Octave.

厌恶性刺激可导致海马位置细胞（hippocampal place cells）重映射（remapping）其放电野，但目前尚不明确该重映射是否参与厌恶性经历的记忆存储。本研究通过对自由活动大鼠（n=14）的CA1区位置细胞开展在体钙成像，解答了这一科学问题。实验中，大鼠首先经训练优先选择短路径以获取食物奖赏，随后通过施加轻微足底电击，训练其回避该短路径。我们通过比较回避习得阶段与回避消退阶段的位置细胞群体向量相似度，评估细胞重映射情况。部分大鼠在全身注射记忆缺失药物东莨菪碱（剂量为1 mg/kg）后接受电击，该剂量可损害回避学习，但不会影响CA1神经元的空间调谐特性与电击诱发反应。结果显示，相较于被遗忘的电击（东莨菪碱给药组），记忆留存的电击（无给药组）可引发更显著的位置细胞重映射；电击诱导的重映射并未使放电野朝向或远离……

MiniLFOV钙成像系统
为记录自由活动动物的钙活动，我们采用了微型显微镜成像系统的大视野版本——"MiniLFOV"（Guo等，2023）。这款开源落射荧光成像相机重量仅13.9 g，视野尺寸为3.6×2.3 mm，视场中心分辨率达2.5 μm，边缘分辨率为4.4 μm。MiniLFOV可实现22 Hz的成像帧率，搭载500万像素CMOS成像传感器，配备可数字化调整焦平面的电润湿透镜，以及支持更长工作距离的模块化镜头配置（本研究使用1.8 mm工作距离，另有3.5 mm可选）。该系统的灵敏度较前代v3微型显微镜提升20倍，较当前v4微型显微镜提升1倍。系统通过一根柔性50 Ω同轴电缆（CW2040-3650SR，Cooner Wire）集成供电、通信与图像数据传输，采用同轴供电滤波技术与串行解串器对，实现基于I2C协议的双向控制通信，以及单向高带宽数据……

MATLAB 2016及以上版本或Octave。