Distinct lines of research in both humans and animals point to a specific role of the hippocampus in both spatial and episodic memory function. The discovery of concept cells in the hippocampus and surrounding medial temporal lobe (MTL) regions suggests that the MTL maps physical and semantic spaces with a similar neural architecture. Here, we studied the emergence of such maps using MTL microwire recordings from 20 patients (9 female, 11 male) navigating a virtual environment featuring salient landmarks with established semantic meaning. We present several key findings. The array of local field potentials in the MTL contains sufficient information for above-chance decoding of subjects' instantaneous location in the environment. Closer examination revealed that as subjects gain experience with the environment the field potentials come to represent both the subjects' locations in virtual space and in high-dimensional semantic space. Similarly, we observe a learning effect on temporal sequence coding. Over time, field potentials come to represent future locations, even after controlling for spatial proximity. This predictive coding of future states, more so than the strength of spatial representations per se, is linked to variability in subjects' navigation performance. Our results thus support the conceptualization of the MTL as a memory space, representing both spatial- and nonspatial information to plan future actions and predict their outcomes.

SIGNIFICANCE STATEMENT Using rare microwire recordings, we studied the representation of spatial, semantic, and temporal information in the human MTL. Our findings demonstrate that subjects acquire a cognitive map that simultaneously represents the spatial and semantic relations between landmarks. We further show that the same learned representation is used to predict future states, implicating MTL cell assemblies as the building blocks of prospective memory functions.

对人类和动物的不同研究表明海马体在空间和情景记忆功能中发挥着特定作用。海马体和周围内侧颞叶 (MTL) 区域概念细胞的发现表明，MTL 使用类似的神经结构映射物理和语义空间。在这里，我们使用 20 名患者（9 名女性，11 名男性）的 MTL 微丝记录来研究此类地图的出现，这些患者在虚拟环境中导航，该虚拟环境具有已确定语义的显着地标。我们提出了几项关键发现。MTL 中的局部场电位阵列包含足够的信息，用于对受试者在环境中的瞬时位置进行超概率解码。更仔细的检查表明，随着受试者获得环境经验，场势开始代表受试者在虚拟空间和高维语义空间中的位置。类似地，我们观察到时间序列编码的学习效果。随着时间的推移，即使在控制了空间邻近性之后，场势也开始代表未来的位置。这种对未来状态的预测编码，比空间表征本身的强度更重要，与受试者导航表现的可变性相关。因此，我们的结果支持 MTL 作为记忆空间的概念，代表空间和非空间信息来规划未来的行动并预测其结果。

意义声明我们利用罕见的微丝录音，研究了人类 MTL 中空间、语义和时间信息的表示。我们的研究结果表明，受试者获得了一张同时代表地标之间的空间和语义关系的认知图。我们进一步表明，相同的学习表示可用于预测未来状态，这表明 MTL 细胞组件是未来记忆功能的构建块。