The hippocampal formation encodes maps of space and a key question in neuroscience is whether its spatial coding principles also provide a universal metric for the organization of nonspatial, conceptual information. Previous work demonstrated directional coding during navigation through a continuous stimulus feature space as well as mapping of distances in a feature space that was relevant for concept learning. Here we provide the first unambiguous evidence for a hippocampal representation of the actual concept space, by showing that the hippocampal distance signal selectively reflects the mapping of specifically conceptually relevant rather than of all feature dimensions. During fMRI scanning of 32 human participants (21 females), we presented everyday objects, which had beforehand been associated with specific values on three continuous feature dimensions. Crucially, only two dimensions were relevant to prior concept learning. We find that hippocampal responses to the objects reflect their relative distances in a space defined along conceptually relevant dimensions compared with distances in a space defined along all feature dimensions. These findings suggest that the hippocampus supports knowledge acquisition by dynamically encoding information in a space spanned along dimensions that are relevant in relation to define concepts.

SIGNIFICANCE STATEMENT How are neural representations of conceptual knowledge organized, such that humans are able to infer never experienced relations or categorize new exemplars? Map-like representations as supported by the hippocampal formation to encode physical space during navigation have been suggested as a suitable format. Here we provide the first evidence for a hippocampal representation of a conceptual space compared with a general feature-based space.

海马结构编码空间图，神经科学中的一个关键问题是其空间编码原理是否也为非空间概念信息的组织提供了通用度量。先前的工作演示了在导航过程中通过连续刺激特征空间进行方向编码以及与概念学习相关的特征空间中的距离映射。在这里，我们通过显示海马距离信号选择性地反映了特定概念相关而不是所有特征尺寸的映射，为实际概念空间的海马表示提供了明确的证据。在对32位人类参与者（21位女性）进行fMRI扫描时，我们展示了日常物品，预先与三个连续要素维上的特定值相关联。至关重要的是，只有两个方面与先前的概念学习有关。我们发现，对象的海马反应反映了沿概念相关尺寸定义的空间中的相对距离，而不是沿所有要素尺寸定义的空间中的距离。这些发现表明，海马通过在沿与定义概念相关的维度跨越的空间中动态编码信息来支持知识获取。我们发现，对象的海马反应反映了沿概念相关尺寸定义的空间中的相对距离，而不是沿所有要素尺寸定义的空间中的距离。这些发现表明，海马通过在沿与定义概念相关的维度跨度的空间中动态编码信息来支持知识获取。我们发现，对象的海马反应反映了沿概念相关尺寸定义的空间中的相对距离，而不是沿所有要素尺寸定义的空间中的距离。这些发现表明，海马通过在沿与定义概念相关的维度跨度的空间中动态编码信息来支持知识获取。

意义陈述如何组织概念知识的神经表示，以使人类能够推断出从未经历过的关系或对新范例进行分类？已经建议由海马结构支持的地图状表示法在导航期间编码物理空间是一种合适的格式。在这里，我们为概念空间与基于一般特征的空间进行海马表示提供了第一个证据。