State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China.
Chinese Institute for Brain Research, Beijing, China.
Nat Commun. 2024 Aug 21;15(1):7185. doi: 10.1038/s41467-024-51582-5.
The consolidation of discrete experiences into a coherent narrative shapes the cognitive map, providing structured mental representations of our experiences. In this process, past memories are reactivated and replayed in sequence, fostering hippocampal-cortical dialogue. However, brain-wide engagement coinciding with sequential reactivation (or replay) of memories remains largely unexplored. In this study, employing simultaneous EEG-fMRI, we capture both the spatial and temporal dynamics of memory replay. We find that during mental simulation, past memories are replayed in fast sequences as detected via EEG. These transient replay events are associated with heightened fMRI activity in the hippocampus and medial prefrontal cortex. Replay occurrence strengthens functional connectivity between the hippocampus and the default mode network, a set of brain regions key to representing the cognitive map. On the other hand, when subjects are at rest following learning, memory reactivation of task-related items is stronger than that of pre-learning rest, and is also associated with heightened hippocampal activation and augmented hippocampal connectivity to the entorhinal cortex. Together, our findings highlight a distributed, brain-wide engagement associated with transient memory reactivation and its sequential replay.
离散经验整合为连贯的叙述形成认知地图，为我们的经验提供结构化的心理表征。在这个过程中，过去的记忆被重新激活并按顺序回放，促进海马体-皮质对话。然而，大脑广泛参与与记忆回放的顺序激活（或重放）仍然在很大程度上未被探索。在这项研究中，我们采用同时进行的 EEG-fMRI 来捕捉记忆重放的空间和时间动态。我们发现，在心理模拟过程中，过去的记忆会通过 EEG 以快速序列的方式被重放。这些短暂的重放事件与海马体和内侧前额叶皮层的 fMRI 活动增强有关。重放的发生增强了海马体和默认模式网络（一组对表示认知地图至关重要的大脑区域）之间的功能连接。另一方面，当受试者在学习后休息时，与任务相关的项目的记忆再激活比学习前的休息更强，并且还与海马体的激活增强以及海马体与内嗅皮层的连接增强有关。总之，我们的研究结果强调了与短暂记忆再激活及其顺序重放相关的分布式、大脑广泛参与。
