Department of Electrical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran.
Rayan Center for Neuroscience and Behavior, Ferdowsi University of Mashhad, Mashhad, Iran.
Sleep. 2019 Jul 8;42(7). doi: 10.1093/sleep/zsz085.
Memories selectively benefit from sleep. In addition to the importance of the consolidation of relevant memories, the capacity to forget unwanted memories is also crucial. We investigated the effect of suppressing unwanted memories on electroencephalography activity of subsequent sleep using a motivated forgetting (MF) paradigm as compared with a control non-forgetting task. Subjects were randomly assigned to nap or no-nap groups. We used a modified version of the think/no-think paradigm with dominant number of no-think words cued to be forgotten and included only subjects capable of suppressing unwanted memories by performing an initial subject inclusion experiment. In both groups and conditions, the performance of the subjects in recalling the word pairs learned in the beginning of the day was evaluated in a final recall test. We found that both nap and no-nap groups recalled significantly less no-think words in the MF condition compared to the control condition. Moreover, for the nap group, in the MF compared to the control condition, spindle power and density increased during stage 2 (S2) whereas they decreased during slow wave sleep (SWS). Interestingly, recall performance of no-think words was negatively correlated with spindle power during S2 whereas it was positively correlated with spindle power during SWS. These results indicate that sleep spindles are sensitive to the previous MF experiences and suggest a differential role of sleep spindles during S2 and SWS in memory processing during sleep.
记忆在睡眠中具有选择性。除了相关记忆巩固的重要性之外，遗忘不需要的记忆的能力也至关重要。我们使用动机遗忘 (MF) 范式来研究抑制不需要的记忆对后续睡眠脑电图活动的影响，并与控制非遗忘任务进行了比较。被试被随机分配到午睡或不午睡组。我们使用了一种改良的思维/不思维范式，其中有大量的不思维词被提示要遗忘，并仅包括那些能够通过进行初始主体纳入实验来抑制不需要的记忆的主体。在两组和两种条件下，在最终的回忆测试中评估了主体在回忆当天开始时学习的单词对的表现。我们发现，与对照组相比，午睡组和不午睡组在 MF 条件下对不思维词的回忆明显减少。此外，对于午睡组来说，与对照组相比，在 MF 条件下，纺锤波功率和密度在 S2 期间增加，而在 SWS 期间减少。有趣的是，不思维词的回忆表现与 S2 期间的纺锤波功率呈负相关，而与 SWS 期间的纺锤波功率呈正相关。这些结果表明，睡眠纺锤波对先前的 MF 体验很敏感，并表明睡眠纺锤波在 S2 和 SWS 期间在睡眠中的记忆处理中发挥了不同的作用。
