女性生理周期对条件性恐惧习得和消退的影响

Influence of Female Menstrual Cycle on the Acquisition and Extinction of Conditioned Fear

动物研究显示,雌激素调节条件性恐惧习得和消退,但是,人类的性激素对条件性恐惧习得和消退的影响还不太清楚。因此,本研究以大学生为研究对象,考察女性不同生理周期对条件性情境恐惧的习得和消退的影响。20名经前期和20名经期女被试暴露于3种情境下:无厌恶刺激情境(N)、可预测情境(P)和不可预测情境(U),预测此3种情境下是否出现厌恶刺激。以在线索条件下和无线索条件下对厌恶刺激的主观预期值为因变量。研究结果显示:在习得阶段,经期女性在P情境下的条件性线索恐惧的主观预期值高于经前期女性;经前期女性在3种情境下的条件性情境恐惧的主观预期值都高于经期女性,但只在N情境和P情境,与经期女性相比,经前期女性对厌恶刺激的主观预期值存在显著差异。在消退阶段,与经期女性相比,经前期女性在3种情境下的条件性情境恐惧的主观预期值更高,且经前期女性对厌恶刺激的主观预期值在N情境和P情境显著高于经期女性。该结果显示,经前期女性对条件性情境恐惧易习得难消退,表明此生理阶段的性激素影响大脑的情绪调节功能,从而影响条件性情境恐惧。

Animal studies have shown that estrogens exert important influence on the acquisition and extinction of conditioned fear, however, the gonadal hormone regulation of fear in human is not known. The purpose of the present study is to examine effects of female menstrual phases on the conditioned fear acquisition and extinction. Twenty female college students in luteal phase and 20 female college students in menses phase participated in the experiment. They were exposed to three conditions： 1） predictable aversive stimuli were signaled by a cue; 2） aversive stimuli were administered unpredictably; 3） no aversive stimuli were anticipated. Aversive unconditioned stimulus （US） expectancy was used to assess anxious responses to the threat cue and to contexts associated with each condition. The results showed that, at the acquisition stage, females in luteal phase （FL） showed higher US expectance for the conditioned context fear in N and P context than females in menses phase （FM）; at the extinction stage, FL had a significantly higher US expectancy in N and P context compared to FM. In other words, the females of luteal phase acquired the conditioned context fear response more effectively and extinguished more slowly than females of menses phase. These data suggest that menstrual cycle can possibly influence the conditioned context fear responses in females. This phenomenon suggests that the gonadal hormone level of luteal phase may affect fear regulation.