Table_1_The Interaction of REM Fragmentation and Night-Time Arousal Modulates Sleep-Dependent Emotional Memory Consolidation.DOCX

The sleep-to-forget, sleep-to-remember (SFSR) hypothesis states that the neurobiological environment provided by rapid-eye movement (REM)-rich sleep decouples the content of an emotional memory from its attendant emotional arousal. This decoupling allows divergent attenuation and enhancement effects (i.e., erosion of the memory’s emotional tone and simultaneous strengthening of its content). However, support for this proposal is mixed. An alternative account suggests there might be convergent attenuation and enhancement (i.e., elevated emotional arousal is positively coupled with enhanced emotional memory). We tested predictions emerging from the SFSR hypothesis using (a) individuals diagnosed with post-traumatic stress disorder (PTSD; n = 21), (b) trauma-exposed non-PTSD individuals (n = 19), and (c) healthy controls (n = 20). We included PTSD-diagnosed individuals because they typically experience altered REM sleep, impaired emotional memory, and heightened emotional arousal in response to threatening stimuli. Participants were assessed before and after both an 8-h period of polysomnographically monitored sleep and an 8-h period of waking activity. The assessment included exposure to negatively valenced, positively valenced, and neutral pictures before the 8-h delay, and a recognition task afterward. We measured emotional arousal by recording psychophysiological responses to the pictures, both pre- and post-delay. Results indicated no significant between-group differences in emotional memory accuracy or arousal. However, after a sleep-filled delay, pictures of all categories were recognized with equal accuracy, whereas after a wake-filled delay, negative pictures were recognized preferentially. Furthermore, the findings demonstrated that a sleep-filled delay was associated with attenuated emotional arousal to pictures of all categories, whereas a wake-filled delay was associated with a rise in emotional arousal across the day. Intriguingly, poorer recognition accuracy for valenced (but not neutral) pictures was predicted by an interaction of increased REM fragmentation and increased emotional arousal. In summary, we found some support for the SFSR hypothesis in the way it describes the REM- and arousal-based mechanisms that process emotional material. We also, however, found disconfirming evidence regarding the outcome of that process (i.e., sleep did not favor consolidation of emotional over neutral memory), and we demonstrated a convergence between attenuation of emotional arousal and weakening of emotional content relative to neutral content.

睡眠-遗忘、睡眠-记忆（SFSR）假说提出，富含快速眼动（rapid-eye movement, REM）睡眠所营造的神经生物学环境，可将情绪性记忆的内容与其伴随的情绪唤醒相分离。这种分离会产生差异化的衰减与增强效应——即削弱记忆的情绪基调，同时强化其记忆内容本身。然而，针对该假说的支持证据存在分歧。另一替代理论则认为，二者可能出现趋同的衰减与增强效应，即情绪唤醒水平升高会与增强的情绪性记忆呈正相关。本研究基于SFSR假说的预测展开检验，招募了三类被试：（1）确诊为创伤后应激障碍（post-traumatic stress disorder, PTSD）的个体（n=21）；（2）曾暴露于创伤但未罹患PTSD的个体（n=19）；（3）健康对照被试（n=20）。之所以纳入PTSD确诊者，是因为此类群体通常存在快速眼动睡眠异常、情绪记忆受损，以及面对威胁性刺激时情绪唤醒水平升高的问题。所有被试均在两种8小时时段前后接受评估：一是经多导睡眠监测的睡眠时段，二是清醒活动时段。评估内容包括：在8小时延迟阶段前，让被试观看负性效价、正性效价及中性效价图片；延迟阶段后进行再认任务。研究通过记录被试对图片的心理生理反应，来测量其情绪唤醒水平，分别在延迟前后进行记录。研究结果显示，各组在情绪记忆准确性或唤醒水平上均无显著组间差异。不过，在经过睡眠填充的延迟阶段后，三类图片的再认准确率趋于一致；而在经过清醒填充的延迟阶段后，负性效价图片的再认准确率更优。此外，研究发现，睡眠填充的延迟阶段与所有类别图片所引发的情绪唤醒水平降低相关，而清醒填充的延迟阶段则与全天情绪唤醒水平升高相关。值得注意的是，效价图片（而非中性图片）的再认准确率更低，这可通过快速眼动睡眠片段化程度升高与情绪唤醒水平升高的交互作用来预测。综上，本研究在SFSR假说所描述的、基于快速眼动睡眠与唤醒的情绪信息加工机制方面，找到了部分支持证据。然而，我们也发现了与该假说的结果预测相悖的证据（即睡眠并未优先巩固情绪性记忆而非中性记忆），同时证实了情绪唤醒衰减与情绪性记忆内容相较于中性记忆内容减弱之间存在趋同效应。