Semantic processing, a core of language comprehension, involves the activation of brain regions dispersed extensively across the frontal, temporal, and parietal cortices that compose the semantic network. To comprehend the functional structure of this semantic network and how it prepares for semantic processing, we investigated its intrinsic functional connectivity (FC) and the relation between this pattern and semantic processing ability in a large sample from the Human Connectome Project (HCP) dataset. We first defined a well-studied brain network for semantic processing, and then we characterized the within-network connectivity (WNC) and the between-network connectivity (BNC) within this network using a voxel-based global brain connectivity (GBC) method based on resting-state functional magnetic resonance imaging (fMRI). The results showed that 97.73% of the voxels in the semantic network displayed considerably greater WNC than BNC, demonstrating that the semantic network is a fairly encapsulated network. Moreover, multiple connector hubs in the semantic network were identified after applying the criterion of WNC > 1 SD above the mean WNC of the semantic network. More importantly, three of these connector hubs (i.e., the left anterior temporal lobe, angular gyrus, and orbital part of the inferior frontal gyrus) were reliably associated with semantic processing ability. Our findings suggest that the three identified regions use WNC as the central mechanism for supporting semantic processing and that task-independent spontaneous connectivity in the semantic network is essential for semantic processing.

语义处理是语言理解的核心，涉及广泛分布在构成语义网络的额叶、颞叶和顶叶皮层的大脑区域的激活。为了理解这个语义网络的功能结构以及它如何为语义处理做准备，我们在人类连接组计划（HCP）数据集中的大样本中研究了其内在的功能连接（FC）以及该模式与语义处理能力之间的关系。我们首先定义了一个经过充分研究的用于语义处理的大脑网络，然后我们使用基于体素的全局大脑连接（GBC）方法来表征该网络内的网络内连接（WNC）和网络间连接（BNC）静息态功能磁共振成像（fMRI）。结果表明，语义网络中 97.73% 的体素显示出比 BNC 更大的 WNC，这表明语义网络是一个相当封装的网络。此外，在应用语义网络的平均 WNC 以上的 WNC > 1 SD 的标准后，识别了语义网络中的多个连接器集线器。更重要的是，其中三个连接器中枢（即左前颞叶、角回和额下回的眼眶部分）与语义处理能力可靠相关。我们的研究结果表明，这三个确定的区域使用 WNC 作为支持语义处理的中心机制，并且语义网络中与任务无关的自发连接对于语义处理至关重要。