Department of Psychology, University of Oregon, Eugene, OR, USA.
Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, USA.
Nat Commun. 2023 Jul 19;14(1):4350. doi: 10.1038/s41467-023-40100-8.
Converging, cross-species evidence indicates that memory for time is supported by hippocampal area CA1 and entorhinal cortex. However, limited evidence characterizes how these regions preserve temporal memories over long timescales (e.g., months). At long timescales, memoranda may be encountered in multiple temporal contexts, potentially creating interference. Here, using 7T fMRI, we measured CA1 and entorhinal activity patterns as human participants viewed thousands of natural scene images distributed, and repeated, across many months. We show that memory for an image's original temporal context was predicted by the degree to which CA1/entorhinal activity patterns from the first encounter with an image were re-expressed during re-encounters occurring minutes to months later. Critically, temporal memory signals were dissociable from predictors of recognition confidence, which were carried by distinct medial temporal lobe expressions. These findings suggest that CA1 and entorhinal cortex preserve temporal memories across long timescales by coding for and reinstating temporal context information.
跨物种的汇聚证据表明，海马体 CA1 区和内嗅皮层支持时间记忆。然而，关于这些区域如何在长时间尺度（例如，数月）上保存时间记忆的证据有限。在长时间尺度上，记忆可能会在多个时间背景下遇到，这可能会产生干扰。在这里，我们使用 7T fMRI，当人类参与者观看数千张自然场景图像时，我们测量了 CA1 和内嗅皮层的活动模式，这些图像分布在多个月中并重复出现。我们表明，对图像原始时间上下文的记忆可以通过在图像第一次遇到时的 CA1/内嗅皮层活动模式在几分钟到几个月后再次遇到时的重新表达程度来预测。至关重要的是，时间记忆信号与识别置信度的预测因素可分离，后者由不同的内侧颞叶表达携带。这些发现表明，CA1 和内嗅皮层通过对时间上下文信息进行编码和重新建立来在长时间尺度上保存时间记忆。
