School of Psychology, University of Birmingham, Birmingham B15 2TT, United Kingdom.
Centre for Human Brain Health, University of Birmingham, Birmingham B15 2TT, United Kingdom.
Proc Natl Acad Sci U S A. 2019 Oct 22;116(43):21834-21842. doi: 10.1073/pnas.1914180116. Epub 2019 Oct 9.
Episodic memories hinge upon our ability to process a wide range of multisensory information and bind this information into a coherent, memorable representation. On a neural level, these 2 processes are thought to be supported by neocortical alpha/beta desynchronization and hippocampal theta/gamma synchronization, respectively. Intuitively, these 2 processes should couple to successfully create and retrieve episodic memories, yet this hypothesis has not been tested empirically. We address this by analyzing human intracranial electroencephalogram data recorded during 2 associative memory tasks. We find that neocortical alpha/beta (8 to 20 Hz) power decreases reliably precede and predict hippocampal "fast" gamma (60 to 80 Hz) power increases during episodic memory formation; during episodic memory retrieval, however, hippocampal "slow" gamma (40 to 50 Hz) power increases reliably precede and predict later neocortical alpha/beta power decreases. We speculate that this coupling reflects the flow of information from the neocortex to the hippocampus during memory formation, and hippocampal pattern completion inducing information reinstatement in the neocortex during memory retrieval.
情景记忆依赖于我们处理各种多感觉信息并将这些信息整合为连贯、可记忆的表现形式的能力。在神经水平上，这两个过程分别被认为分别由新皮质的α/β去同步化和海马的θ/γ同步化来支持。直观地说，这两个过程应该结合起来成功地创建和检索情景记忆，但这一假设尚未经过实证检验。我们通过分析在两个联想记忆任务中记录的人类颅内脑电图数据来解决这个问题。我们发现，在情景记忆形成过程中，海马体“快”γ（60 至 80 赫兹）功率的增加可靠地先于并预测新皮质α/β（8 至 20 赫兹）功率的降低；然而，在情景记忆检索过程中，海马体“慢”γ（40 至 50 赫兹）功率的增加可靠地先于并预测新皮质α/β功率的降低。我们推测这种耦合反映了在记忆形成过程中信息从新皮质流向海马体的情况，以及在记忆检索过程中，海马体模式完成诱导信息在新皮质中的重新出现。
