Objective To investigate the way of fear conditioning memory model evoked and erased by foot-shock in tree shrew. Methods First, detect the tree shrew activities regularly in light/dark box. Second, test a suitable voltage degree of foot shock on tree shrew. Third, investigate the memory formation and erasing of fear conditioning on tree shrew of trial group. Results The duration of tree shrew (n=4) stay in the dark-box was significantly lon-ger than that of in the light box (P<0. 01) in normal condition. In the same environment of two light boxes, given different voltage degrees, the durations of tree shrew (n=6) stay in the stimulating chamber gradually reduced and the durations of tree shrew stay had significant difference between stimulatus chamber and no stimulatus chamber when the stimulus voltage up to 12 V ( P<0. 05 ) , 16 V ( P<0. 01 ) and 20 V ( P<0. 01 ) . The animal of trial group ( n=4 ) could build up the fear conditioning memory of the dark box with the stimulus of 16 V foot-shock in the dark box ( P<0. 001 ) . After formation of the fear conditioning memory, the same stimulus in light box ap-peared for 4 days. The durations of tree shrew stay in trial group (n=4) decreased in light box, and there was no significant difference between the trial group and the control group. Conclusion Tree shrew prefers to stay in the dark box. The suitable voltage for foot-shock on tree shrew is 16 V. The fear conditioning memory can be evoked and erased by foot-shock.%目的 探索足底电击诱导树鼩条件恐惧记忆模型的建立及抹除方法. 方法 测定在无刺激条件下,树鼩在明暗箱中的活动规律;然后用梯度刺激实验测定合适的足底电击电压;最后用合适的电压通过足底电击诱导并建立实验组树鼩条件恐惧记忆模型并抹除其记忆. 结果 正常条件下,树鼩(n=4)在暗箱中的停留时间明显多于明箱中的停留时间(P<0. 01);在两明箱中,足底电压梯度刺激实验显示,随着刺激电压的增加,树鼩(n=6)在有刺激的隔间中的停留时间逐渐减少. 12 V以后树鼩在有刺激隔间与无刺激隔间的停留时间差异有统计学意义[12 V(P <0. 05)、16 V(P <0. 01)、20 V(P<0. 01)];实验组(n=4)暗箱用16 V刺激电压足底电击能够形成明显的恐惧记忆( P<0. 001 ). 在形成明显的恐惧记忆后,在明箱中给予相应的足底电击4 d,实验组(n=4)树鼩在明箱中停留的时间逐渐减少,与对照组比较差异无统计学意义. 结论 树鼩更趋于停留在暗箱中;16 V为较为适合的足底电击电压;条件恐惧记忆能够被诱导并且被新的刺激完全抹除.
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