语义表示的中枢理论将语义知识的神经基础分为两个基本组成部分:感觉运动模态特定区域和至关重要的语义中枢区域。我们先前在语义痴呆患者中的研究发现,枢纽区域位于左梭状回。然而,因为这个区域位于语义痴呆患者的脑损伤范围内,尚不清楚语义缺陷是由枢纽区域本身的结构损伤还是由其与其他大脑区域的断开引起的。中风患者左梭状回没有任何损伤,但在语义处理中表现出模态和模态特异性缺陷。因此,在这项研究中,我们从脑网络角度对79例卒中患者的语义中枢区域进行了验证,并探讨了与之相关的白质连接.首先,我们收集了一般语义任务和模态特定语义任务的弥散加权成像和行为表现数据(评估形式上的对象知识,颜色,动议,声音,操纵和功能)。然后,我们使用相关性和回归分析来检查中风患者全脑结构网络中脑区域的节点程度值与一般语义表现之间的关联。结果表明,左梭状回的连通性显着预测一般语义表现,表明该区域是语义中心。要识别语义中心的语义相关连接,然后,我们将连接到左梭状回的每个束的白质完整性值分别与一般和特定于模态的语义处理性能相关联。我们发现,中枢区域通过与左上颞极的白质连接来完成一般语义处理,颞中回,颞下回和海马。中枢区域和左侧海马体之间的连通性,颞上极,颞中回,颞下回和海马旁回在物体形式上有差异,颜色,动议,声音,操作和功能处理。在统计上消除了潜在混杂变量的影响(即全脑病变体积,感兴趣区域的病变体积和在非语义控制任务上的表现),观察到的效果仍然显著。一起,我们的研究结果支持左梭状回作为卒中患者的语义枢纽区域的作用,并揭示了其在网络中的关键连通性.本研究为人脑语义记忆的神经解剖学组织提供了新的见解和证据。
The hub-and-spoke theory of semantic representation fractionates the neural underpinning of semantic knowledge into two essential components: the sensorimotor modality-specific regions and a crucially important semantic hub region. Our previous study in patients with semantic dementia has found that the hub region is located in the left fusiform gyrus. However, because this region is located within the brain damage in patients with semantic dementia, it is not clear whether the semantic deficit is caused by structural damage to the hub region itself or by its disconnection from other brain regions. Stroke patients do not have any damage to the left fusiform gyrus, but exhibit amodal and modality-specific deficits in semantic processing. Therefore, in this study, we validated the semantic hub region from a brain network perspective in 79 stroke patients and explored the white matter connections associated with it. First, we collected data of diffusion-weighted imaging and behavioural performance on general semantic tasks and modality-specific semantic tasks (assessing object knowledge on form, colour, motion, sound, manipulation and function). We then used correlation and regression analyses to examine the association between the nodal degree values of brain regions in the whole-brain structural network and general semantic performance in the stroke patients. The results revealed that the connectivity of the left fusiform gyrus significantly predicted general semantic performance, indicating that this region is the semantic hub. To identify the semantic-relevant connections of the semantic hub, we then correlated the white matter integrity values of each tract connected to the left fusiform gyrus separately with performance on general and modality-specific semantic processing. We found that the hub region accomplished general semantic processing through white matter connections with the left superior temporal pole, middle temporal gyrus, inferior temporal gyrus and hippocampus. The connectivity between the hub region and the left hippocampus, superior temporal pole, middle temporal gyrus, inferior temporal gyrus and parahippocampal gyrus was differentially involved in object form, colour, motion, sound, manipulation and function processing. After statistically removing the effects of potential confounding variables (i.e. whole-brain lesion volume, lesion volume of regions of interest and performance on non-semantic control tasks), the observed effects remained significant. Together, our findings support the role of the left fusiform gyrus as a semantic hub region in stroke patients and reveal its crucial connectivity in the network. This study provides new insights and evidence for the neuroanatomical organization of semantic memory in the human brain.