The hippocampus is an essential brain area for learning and memory. However, the network mechanisms underlying memory storage, consolidation and retrieval remain incompletely understood. Place cell sequences during theta oscillations are thought to be replayed during non-theta states to support consolidation and route planning. In animals with medial entorhinal cortex (MEC) lesions, the temporal organization of theta-related hippocampal activity is disrupted, which allows us to test whether replay is also compromised. Two different analyses-comparison of co-activation patterns between running and rest epochs and analysis of the recurrence of place cell sequences-reveal that the enhancement of replay by behavior is reduced in MEC-lesioned versus control rats. In contrast, the degree of intrinsic network structure prior and subsequent to behavior remains unaffected by MEC lesions. The MEC-dependent temporal coordination during theta states therefore appears to facilitate behavior-related plasticity, but does not disrupt pre-existing functional connectivity.

中文翻译：

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没有内侧内嗅皮层的输入，海马CA1的重播变得不那么突出，但变得更加僵硬。

海马是学习和记忆的必不可少的大脑区域。但是，内存存储，合并和检索所基于的网络机制仍未完全了解。人们认为在theta振荡期间放置单元格序列会在非theta状态下重播，以支持合并和路线规划。在具有内侧内嗅皮层（MEC）病变的动物中，与θ相关的海马活动的时间组织受到破坏，这使我们能够测试重放是否也受到损害。两种不同的分析-跑步和休息时期之间共激活模式的比较，以及位置细胞序列重复发生的分析-揭示在MEC病变的大鼠与对照组相比，行为重演的增强降低了。相比之下，行为之前和之后的内在网络结构程度仍不受MEC病变的影响。因此，在θ状态期间依赖于MEC的时间协调似乎促进了与行为相关的可塑性，但并未破坏先前存在的功能连接性。