The hippocampus replays experiences during quiet rest periods, and this replay benefits subsequent memory. A critical open question is how memories are prioritized for this replay. We used functional magnetic resonance imaging (fMRI) pattern analysis to track item-level replay in the hippocampus during an awake rest period after participants studied 15 objects and completed a memory test. Objects that were remembered less well were replayed more during the subsequent rest period, suggesting a prioritization process in which weaker memories-memories most vulnerable to forgetting-are selected for replay. In a second session 12 hours later, more replay of an object during a rest period predicted better subsequent memory for that object. Replay predicted memory improvement across sessions only for participants who slept during that interval. Our results provide evidence that replay in the human hippocampus prioritizes weakly learned information, predicts subsequent memory performance, and relates to memory improvement across a delay with sleep.

中文翻译：

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休息期间的人类海马重放会优先考虑弱知识，并预测记忆表现。

海马在安静的休息时间重播经验，并且此重播有益于后续的记忆。一个关键的悬而未决的问题是，如何为该重放优先考虑存储器。在参与者研究了15个对象并完成了一项记忆测试后，我们在清醒的休息时间内使用功能性磁共振成像（fMRI）模式分析来跟踪海马中的项目级重播。记忆力较差的对象会在随后的休息时间内进行更多的重放，这表明在优先级排序过程中，较弱的记忆（最容易遗忘的记忆）被选择进行重放。在12小时后的第二个会话中，对象在休息期间的重播次数更多，预示该对象的后续记忆更好。重播仅针对在该时间间隔内睡着的参与者，预测跨会话的内存改善。