目的：探究雌性和雄性C57野生型小鼠在条件性恐惧消退实验中是否存在行为学上的差异，为在恐惧 学习与消退相关研究中平等使用不同性别的小鼠提供参考。方法：通过声音介导的条件性恐惧学习、消退、 检索实验，检测条件刺激呈现时的恐惧水平、僵直次数、单次僵直的恐惧水平以及运动能力等指标，比较不同 性别小鼠之间的行为学差异。结果：在条件性恐惧学习和消退实验中，雌性和雄性小鼠在4个行为学指标上 无显著差异；条件性恐惧检索实验中雌性小鼠在第1次条件刺激呈现时单次僵直恐惧水平更高，其余行为学 指标无显著差异。 结论：不同性别的C57 野生型小鼠在条件性恐惧学习和消退实验中没有行为学差异，可 平等地用于研究中；在对恐惧消退记忆的维持能力上雌性和雄性小鼠可能存在差异，在恐惧记忆研究中要谨 慎使用。

To investigate whether behavioral differences exist between female and male wild-type C57 mice in conditioned fear extinction experiments, providing a reference for the equal use of both sexes in fear conditioning and extinction-related studies. Methods: Fear levels, freezing episodes, freezing level per episode, and locomotor activity during conditioned stimulus presentation were measured through auditory-cued fear conditioning, extinction, and retrieval experiments. Behavioral differences between sexes were compared. Results: In fear conditioning and extinction experiments, no significant differences were observed between female and male mice across the four behavioral metrics. During the fear extinction retrieval test, female mice exhibited a higher freezing level per episode upon the first conditioned stimulus presentation, while no significant differences were found in other metrics. Conclusion: Wild-type C57 mice of both sexes show no behavioral differences in fear conditioning and extinction experiments, supporting their equal use in such studies. However, potential sex-based differences in the ability to maintain extinction memory suggest caution when investigating fear memory retention.