Longitudinal Differences in Human Hippocampal Connectivity During Episodic Memory Processing.
Longitudinal Differences in Human Hippocampal Connectivity During Episodic Memory Processing.
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DOI：
10.1093/texcom/tgaa010
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发表时间：
2020-01-01
影响因子：
--
通讯作者：
Lega, Bradley
中科院分区：
文献类型：
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作者：
Choi, Kyuwan;Bagen, Lisa;Lega, Bradley
纵向海马功能专业化的问题是至关重要的人类情景记忆，因为这种现象的准确理解将影响记忆功能的理论，并带来实际后果的颞叶手术患者的临床管理。实施的机器人辅助立体脑电描记术技术癫痫地图提供了我们的小组有机会获得记录同时从前部和后部的人类海马，使我们能够创建一个无与伦比的数据集的人类受试者与同时的前部和后部海马记录沿着与几个皮层区域。利用这些数据，我们解决了几个关键问题，在人类记忆中的功能海马连接。首先，我们问是否在情节记忆编码和检索的功能网络是显着不同的前与后海马（PH）。我们还研究了2- 5 Hz与4- 9 Hz θ频率范围内的连接如何不同，直接解决了这些独立频带中的每一个在大脑皮层相互作用中的相对贡献。虽然我们报告了一些重叠的连接，但我们观察到的证据表明，在与额叶和顶叶连接以及聚集连接的半球差异相关的记忆编码过程中，前后海马网络存在明显差异。我们根据建议的AT/PM记忆系统框架这些发现。我们还观察到前海马和后海马网络之间不同的编码与检索连接模式，我们发现右半球的PH整体连接更大，并且这些网络在额叶和顶叶连接方面存在显着差异。我们把这些发现的背景下，现有的理论治疗人类记忆系统，特别是建议的AT/PM系统。在记忆提取过程中，我们观察到皮层和海马之间的慢θ（2- 5 Hz）和快θ（4- 9 Hz）连接之间的显着差异。最后，我们测试这些不同的θ频率振荡如何在海马内传播，使用相位斜率指数来估计编码和检索过程中慢θ和快θ振荡的方向。我们发现的证据表明，2- 5 Hz的振荡旅行在后到前的方向，而5- 9 Hz的振荡旅行从前到后。两者合计，我们的研究结果描述了记忆相关的功能连接的差异沿着人类海马体的纵轴，将告知解释模型的海马体功能，试图整合啮齿动物和人类的数据。
The question of longitudinal hippocampal functional specialization is critical to human episodic memory because an accurate understanding of this phenomenon would impact theories of mnemonic function and entail practical consequences for the clinical management of patients undergoing temporal lobe surgery. The implementation of the robotically assisted stereo electroencephalography technique for seizure mapping has provided our group with the opportunity to obtain recordings simultaneously from the anterior and posterior human hippocampus, allowing us to create an unparalleled data set of human subjects with simultaneous anterior and posterior hippocampal recordings along with several cortical regions. Using these data, we address several key questions governing functional hippocampal connectivity in human memory. First, we ask whether functional networks during episodic memory encoding and retrieval are significantly different for the anterior versus posterior hippocampus (PH). We also examine how connections differ across the 2-5Hz versus 4-9Hz theta frequency ranges, directly addressing the relative contribution of each of these separate bands in hippocampal-cortical interactions. While we report some overlapping connections, we observe evidence of distinct anterior versus posterior hippocampal networks during memory encoding related to frontal and parietal connectivity as well as hemispheric differences in aggregate connectivity. We frame these findings in light of the proposed AT/PM memory systems. We also observe distinct encoding versus retrieval connectivity patterns between anterior and posterior hippocampal networks, we find that overall connectivity is greater for the PH in the right hemisphere, and further that these networks significantly differ in terms of frontal and parietal connectivity. We place these findings in the context of existing theoretical treatments of human memory systems, especially the proposed AT/PM system. During memory retrieval, we observe significant differences between slow-theta (2-5Hz) and fast-theta (4-9Hz) connectivity between the cortex and hippocampus. Finally, we test how these distinct theta frequency oscillations propagate within the hippocampus, using phase slope index to estimate the direction slow-theta and fast-theta oscillations travel during encoding and retrieval. We uncover evidence that 2-5Hz oscillations travel in the posterior-to-anterior direction, while 5-9Hz oscillations travel from anterior-to-posterior. Taken together, our findings describe mnemonically relevant functional connectivity differences along the longitudinal axis of the human hippocampus that will inform interpretation of models of hippocampal function that seek to integrate rodent and human data.