The consolidation of spatial memory depends on the reactivation (‘replay’) of hippocampal place cells that were active during recent behaviour. Such reactivation is observed during sharp-wave ripples (SWRs)—synchronous oscillatory electrical events that occur during non-rapid-eye-movement (non-REM) sleep 1 – 8 and whose disruption impairs spatial memory 3 , 5 , 6 , 8 . Although the hippocampus also encodes a wide range of non-spatial forms of declarative memory, it is not yet known whether SWRs are necessary for such memories. Moreover, although SWRs can arise from either the CA3 or the CA2 region of the hippocampus 7 , 9 , the relative importance of SWRs from these regions for memory consolidation is unknown. Here we examine the role of SWRs during the consolidation of social memory—the ability of an animal to recognize and remember a member of the same species—focusing on CA2 because of its essential role in social memory 10 – 12 . We find that ensembles of CA2 pyramidal neurons that are active during social exploration of previously unknown conspecifics are reactivated during SWRs. Notably, disruption or enhancement of CA2 SWRs suppresses or prolongs social memory, respectively. Thus, SWR-mediated reactivation of hippocampal firing related to recent experience appears to be a general mechanism for binding spatial, temporal and sensory information into high-order memory representations, including social memory. Social memory is consolidated in the brain through the reactivation of neuronal firing by sharp-wave ripples in the CA2 region of the hippocampus, in a similar way to the consolidation of spatial memory.

中文翻译：

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海马 CA2 尖波涟漪重新激活并促进社会记忆

空间记忆的巩固取决于在最近的行为中活跃的海马位置细胞的重新激活（“重放”）。在尖波波纹 (SWR) 期间观察到这种重新激活 - 同步振荡电事件发生在非快速眼动 (非快速眼动) 睡眠 1-8 期间，其中断会损害空间记忆 3、5、6、8。尽管海马体还编码了广泛的非空间形式的陈述性记忆，但尚不清楚 SWR 是否对于此类记忆是必要的。此外，虽然 SWR 可以来自海马 7、9 的 CA3 或 CA2 区域，但来自这些区域的 SWR 对于记忆巩固的相对重要性尚不清楚。在这里，我们研究了 SWR 在社会记忆巩固过程中的作用——动物识别和记住同一物种成员的能力——重点关注 CA2，因为它在社会记忆中的重要作用 10-12。我们发现，在对以前未知的同种进行社会探索期间活跃的 CA2 锥体神经元的集合在 SWR 期间被重新激活。值得注意的是，CA2 SWR 的破坏或增强分别抑制或延长社会记忆。因此，与近期经验相关的 SWR 介导的海马放电再激活似乎是将空间、时间和感觉信息绑定到包括社会记忆在内的高级记忆表征中的一般机制。