White matter basis for the hub-and-spoke semantic representation: evidence from semantic dementia

作者：Yan Chen, Lin Huang, Keliang Chen, Junhua Ding, Yumei Zhang, Qing Yang, Yingru Lv, Zaizhu Han, Qihao Guo · 发表于：Brain · 年份：2020 · DOI：10.1093/brain/awaa057 · 被引用次数：43 · 研究领域：Neurobiology of Language and Bilingualism、EEG and Brain-Computer Interfaces、Dementia and Cognitive Impairment Research

The hub-and-spoke semantic representation theory posits that semantic knowledge is processed in a neural network, which contains an amodal hub, the sensorimotor modality-specific regions, and the connections between them. The exact neural basis of the hub, regions and connectivity remains unclear. Semantic dementia could be an ideal lesion model to construct the semantic network as this disease presents both amodal and modality-specific semantic processing (e.g. colour) deficits. The goal of the present study was to identify, using an unbiased data-driven approach, the semantic hub and its general and modality-specific semantic white matter connections by investigating the relationship between the lesion degree of the network and the severity of semantic deficits in 33 patients with semantic dementia. Data of diffusion-weighted imaging and behavioural performance in processing knowledge of general semantic and six sensorimotor modalities (i.e. object form, colour, motion, sound, manipulation and function) were collected from each subject. Specifically, to identify the semantic hub, we mapped the white matter nodal degree value (a graph theoretical index) of the 90 regions in the automated anatomical labelling atlas with the general semantic abilities of the patients. Of the regions, only the left fusiform gyrus was identified as the hub because its structural connectivity strength (i.e. nodal degree value) could significantly predict the general semantic processing of the pat...