生理周期对情景记忆的影响

来自进化心理学的理论及研究结果提示, 女性性激素可能是情景记忆的重要影响因素, 但是, 具体机制尚不清晰。本研究以女性生理周期性激素水平的自然变化构成的两个时期(卵泡后期、黄体中期)为自变量, 利用“What-Where-When Task”情景记忆任务(实验1), 结合事件相关电位(event-related potential, ERP)技术(实验2), 探讨生理周期不同阶段完成情景记忆任务的成绩及其可能的内在机制。实验1招募生理周期稳定的33名女性为被试, 在卵泡后期和黄体中期各参加一次实验, 随机顺序依次完成O任务(仅记忆物品, object)、P任务(仅记忆物品位置, position)、OO任务(记忆物品及其呈现顺序, object + order)、OP任务(记忆物品及其呈现位置, object + position)以及PO任务(记忆物品呈现位置及顺序, position + order)。结果发现, 在完成PO任务时, 黄体中期的回忆正确率显著高于卵泡后期。实验2借用事件相关电位技术, 进一步探究生理周期影响情景记忆PO任务的原因, 结果发现, 黄体中期额叶脑区的P300以及LPC波的振幅显著大于卵泡后期, 且完成PO任务时的感受性与右侧额叶P300振幅显著正相关。基于上述ERP的结果, 可以认为, 黄体中期在PO任务上的好成绩可能得益于显著增强的认知控制能力, 这一解释符合前人研究结论。总之, 本研究发现：生理周期对情景记忆中客体的空间位置与时间顺序整合的记忆产生显著影响, 黄体中期的记忆效果显著好于卵泡后期, 可能是因为该时期显著增强的认知控制能力。本研究有望为理解影响情景记忆的因素提供新的视角。

An effect of menstrual cycle phase on episodic memory

Episodic memory refers to the recollection of personally experienced events in a specific context. Evolutionary psychology findings have suggested that female sex hormones may be important influencing factors for episodic memory, but the specific mechanism underlying these influences are unclear. The aim of the present study was to examine whether periodic fluctuations of estrogen and progesterone over the menstrual cycle may influence episodic memory in the What-Where-When Task. Healthy women with stable menstrual cycles and not taking exogenous hormones were recruited for two experiments. In Experiment 1, episodic memory was tested with 33 women during the late follicular phase (FP) and during the mid-luteal phase (LP) with the following five tasks employing images of objects as stimuli: object-only, position-only, object-position binding, object-order binding, and position-order binding. The testing order was counter-balanced across subjects. After a learning phase, participants were asked to recollect elements according to the requirements of each task, and the accuracy rates of their recollections were recorded as dependent variables. The results of Experiment 1 showed that recollection accuracy differed between the late FP and mid-LP for only one of the tasks, namely the position-order binding task. Thus, in Experiment 2, event-related potentials (ERPs) were recorded during the performance of the position-order binding task, while recollection accuracy performance was evaluated. For the position-order binding task in both experiments, a significantly higher response accuracy rate was observed in the mid-LP than in the late FP. Regarding the ERP results, amplitudes of the P300 component and the late positive component (LPC) in frontal cortices, which has associated with cognitive control, were found to be higher in the mid-LP than in the late FP. The present results support the notion that people may have greater cognitive control of episodic memory in the mid-LP than in the late FP. In conclusion, the present results showed that menstrual cycle phase affects position-order binding memory performance and concomitant neural activities. Better episodic memory performance during the mid-LP, relative to the late FP, could be attributed to better cognitive control ability. This study provides new information on physiological factors that can affect episodic memory.