Cerebral Function Unit, Greater Manchester Neuroscience Centre, Salford Royal NHS Foundation Trust, Salford, UK; Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
Cerebral Function Unit, Greater Manchester Neuroscience Centre, Salford Royal NHS Foundation Trust, Salford, UK; Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
Cortex. 2018 Oct;107:188-203. doi: 10.1016/j.cortex.2017.08.024. Epub 2017 Aug 31.
Semantic dementia, a circumscribed disorder of semantic knowledge, provides a unique model for understanding the neural basis for semantic representation. The study addressed areas of contention: the relative roles of the left and right temporal lobe, the contribution of anterior versus posterior temporal cortex and the status of the anterior temporal lobes as amodal hub. Naming and word comprehension was examined in 41 semantic dementia patients, 31 with left-predominant and 10 right-predominant atrophy. In keeping with expectation, naming and comprehension were significantly poorer in left-predominant patients. Structural magnetic resonance image analysis, using a visual rating scale, showed strong inverse correlations between naming scores and severity of both left anterior and posterior temporal lobe atrophy. By contrast, comprehension performance was more strongly correlated with left posterior temporal atrophy. Analysis of naming errors revealed a correlation between anterior temporal atrophy and associative/functional descriptive responses, implying availability of semantic information. By contrast, 'don't know' responses, indicative of loss of semantic knowledge, were linked to left posterior temporal lobe atrophy. Semantic errors, the hallmark of semantic dementia, were linked to right hemisphere atrophy, especially the right posterior temporal lobe. Matched visual-verbal tasks (famous face and name identification, Pyramids and Palm trees pictures and words, animal knowledge from 3-D models and animal names) administered to nine patients elicited variable correspondence between performance on nonverbal and verbal versions of the task. Marked performance dissociations were demonstrated in some patients: poorer understanding of names/words in left-predominant patients and of faces/pictures/models in right-predominant cases. The findings are compatible with the notion of the anterior temporal lobes as areas of convergence, but are less easily accommodated within the framework of amodal conceptual representation. The data, which reconcile some apparent contradictions in the literature, are discussed in the light of the nature and distribution of degenerative change in semantic dementia.
语义痴呆症是一种局限于语义知识的紊乱，为理解语义表现的神经基础提供了一个独特的模型。该研究解决了一些争议问题：左、右颞叶的相对作用，前颞叶和后颞叶皮质的贡献，以及前颞叶作为非模态中枢的地位。对 41 名语义痴呆症患者（31 名左侧优势萎缩和 10 名右侧优势萎缩）进行了命名和单词理解测试。与预期一致，左侧优势患者的命名和理解能力明显较差。使用视觉评分量表的结构磁共振图像分析显示，命名得分与左前颞叶和后颞叶萎缩的严重程度呈强烈的负相关。相比之下，理解能力与左后颞叶萎缩的相关性更强。对命名错误的分析表明，前颞叶萎缩与联想/功能描述性反应之间存在相关性，这表明存在语义信息。相比之下，“不知道”的反应表明语义知识的丧失与左后颞叶萎缩有关。语义错误是语义痴呆症的标志，与右侧萎缩有关，尤其是右侧后颞叶。对 9 名患者进行了匹配的视觉语言任务（著名人脸和姓名识别、金字塔和棕榈树图片和单词、3D 模型和动物名称的动物知识），测试结果表明，在非语言和语言版本的任务中，患者的表现存在差异。在一些患者中表现出明显的表现差异：左侧优势患者对姓名/单词的理解能力较差，右侧优势患者对人脸/图片/模型的理解能力较差。这些发现与前颞叶作为汇聚区域的概念一致，但在非模态概念表示的框架内较难解释。根据语义痴呆症退行性变化的性质和分布，讨论了这些数据，以解决文献中的一些明显矛盾。
