Hexadirectional Modulation of High-Frequency Electrophysiological Activity in the Human Anterior Medial Temporal Lobe Maps Visual Space
Hexadirectional Modulation of High-Frequency Electrophysiological Activity in the Human Anterior Medial Temporal Lobe Maps Visual Space
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DOI：
10.1016/j.cub.2018.09.035
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发表时间：
2018-10
期刊：
影响因子：
9.2
通讯作者：
T. Staudigl;M. Leszczyński;J. Jacobs;S. Sheth;C. Schroeder;O. Jensen;Christian F. Doeller
中科院分区：
文献类型：
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作者：
T. Staudigl;M. Leszczyński;J. Jacobs;S. Sheth;C. Schroeder;O. Jensen;Christian F. Doeller
网格单元是空间导航的核心构件之一[1]。啮齿动物内嗅觉皮质网格细胞的单细胞记录揭示了空间导航过程中局部环境的六角形编码[1]。在虚拟导航期间的人类单细胞记录中也发现了类似网格的活动[2]。人类功能磁共振成像研究进一步提供了证据，即网格状信号也可以在宏观水平上获得[3-7]。非人灵长类动物[8]和人类[9，10]的研究都表明，内嗅皮层中的网格状编码在运动过程中超越了空间导航，为视觉探索过程中视觉空间的网格状映射提供了证据-类似于啮齿类动物在空间导航期间的网格细胞位置编码。然而，人类网格密码的电生理学相关性仍不清楚。在这里，我们基于两个独立的数据集：健康受试者的非侵入性脑磁图(MEG)和癫痫患者的内嗅脑电信号(EEG)记录，提供了人类高频活动对视觉空间进行网格状、六向编码的证据。这两个数据集都一致地显示了宽带高频活动(60-120 GHz)的六向调制。我们的发现首次为网格状的脑磁图信号提供了证据，表明人类内嗅皮层以网格状的方式对视觉空间进行编码[8-10]，并支持网格编码超越了运动过程中的环境映射的观点[4-6，11]。由于其毫秒级的精度，脑磁图记录允许在相关行为期间将网格状活动与历元联系起来，从而为以高时间分辨率进行基于脑磁图的新的网格编码研究打开了可能性。
Grid cells are one of the core building blocks of spatial navigation [1]. Single-cell recordings of grid cells in the rodent entorhinal cortex revealed hexagonal coding of the local environment during spatial navigation [1]. Grid-like activity has also been identified in human single-cell recordings during virtual navigation [2]. Human fMRI studies further provide evidence that grid-like signals are also accessible on a macroscopic level [3–7]. Studies in both non-human primates [8] and humans [9, 10] suggest that grid-like coding in the entorhinal cortex generalizes beyond spatial navigation during locomotion, providing evidence for grid-like mapping of visual space during visual exploration—akin to the grid cell positional code in rodents during spatial navigation. However, electrophysiological correlates of the grid code in humans remain unknown. Here, we provide evidence for grid-like, hexadirectional coding of visual space by human high-frequency activity, based on two independent datasets: non-invasive magnetoencephalography (MEG) in healthy subjects and entorhinal intracranial electroencephalography (EEG) recordings in an epileptic patient. Both datasets consistently show a hexadirectional modulation of broadband high-frequency activity (60–120 Hz). Our findings provide first evidence for a grid-like MEG signal, indicating that the human entorhinal cortex codes visual space in a grid-like manner [8–10], and support the view that grid coding generalizes beyond environmental mapping during locomotion [4–6, 11]. Due to their millisecond accuracy, MEG recordings allow linking of grid-like activity to epochs during relevant behavior, thereby opening up the possibility for new MEG-based investigations of grid coding at high temporal resolution.