Department of Psychology, Northwestern University, Evanston, IL, 60208, USA.
MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, CB2 7EF, UK.
Sci Rep. 2021 Jan 14;11(1):1383. doi: 10.1038/s41598-020-80671-w.
Sleep's role in memory consolidation is widely acknowledged, but its role in weakening memories is still debated. Memory weakening is evolutionary beneficial and makes an integral contribution to cognition. We sought evidence on whether sleep-based memory reactivation can facilitate memory suppression. Participants learned pairs of associable words (e.g., DIET-CREAM) and were then exposed to hint words (e.g., DIET) and instructed to either recall ("think") or suppress ("no-think") the corresponding target words (e.g., CREAM). As expected, suppression impaired retention when tested immediately after a 90-min nap. To test if reactivation could selectively enhance memory suppression during sleep, we unobtrusively presented one of two sounds conveying suppression instructions during sleep, followed by hint words. Results showed that targeted memory reactivation did not enhance suppression-induced forgetting. Although not predicted, post-hoc analyses revealed that sleep cues strengthened memory, but only for suppressed pairs that were weakly encoded before sleep. The results leave open the question of whether memory suppression can be augmented during sleep, but suggest strategies for future studies manipulating memory suppression during sleep. Additionally, our findings support the notion that sleep reactivation is particularly beneficial for weakly encoded information, which may be prioritized for consolidation.
睡眠在记忆巩固中的作用已被广泛认可，但它在削弱记忆方面的作用仍存在争议。记忆削弱是进化有益的，并对认知做出了不可或缺的贡献。我们寻求证据来证明基于睡眠的记忆再激活是否可以促进记忆抑制。参与者学习了可联想的单词对（例如，DIET-CREAM），然后暴露于提示词（例如，DIET），并被指示回忆（“思考”）或抑制（“不思考”）相应的目标词（例如，CREAM）。正如预期的那样，在 90 分钟小睡后立即进行测试时，抑制会损害保留。为了测试再激活是否可以在睡眠期间选择性地增强记忆抑制，我们在睡眠期间不引人注目地呈现了两个传达抑制指令的声音之一，然后是提示词。结果表明，目标记忆再激活并没有增强抑制引起的遗忘。尽管没有预测到，但事后分析显示，睡眠线索增强了记忆，但仅针对在睡眠前编码较弱的抑制对。结果使睡眠期间是否可以增强记忆抑制的问题悬而未决，但为未来在睡眠期间操纵记忆抑制的研究提供了策略。此外，我们的发现支持这样一种观点，即睡眠再激活对于弱编码的信息特别有益，这些信息可能被优先用于巩固。
