Anosognosia for hemiplegia (AHP) is a complex syndrome whose neural correlates are still under investigation. One hypothesis, mainly based on lesion mapping studies, is that AHP reflects a breakdown of neural systems of the right hemisphere involved in motor function. However, more recent theories have suggested that AHP may represent a disorder of cognitive systems involved in belief updating, self-referential or body processing. Two recent studies, using a method to estimate the degree of white matter disconnection from lesions, have indeed shown that patients with AHP suffer from damage of several long-range white matter pathways in association cortex. Here, we use a similar indirect disconnection approach to study a group of patients with motor deficits without anosognosia (hemiparesis or hemiplegia, HP, n = 35), or motor deficits with AHP (n = 28). The HP lesions came from a database of stroke patients, while cases of AHP were selected from the published literature. Lesions were traced into an atlas from illustrations of the publications using a standard method. There was no region in the brain that was more damaged in AHP than HP. In terms of structural connectivity, AHP patients had a similar pattern of disconnection of motor pathways to HP patients. However, AHP patients also showed significant disconnection of the right temporo-parietal junction, right insula, right lateral and medial prefrontal cortex. These associative cortical regions were connected through several white matter tracts, including superior longitudinal fasciculus III, arcuate, fronto-insular, frontal inferior longitudinal, and frontal aslant. These tracts connected regions of different cognitive networks: default, ventral attention, and cingulo-opercular. These results were not controlled for clinical variables as concomitant symptoms and other disorders of body representation were not always available for co-variate analysis. In conclusion, we confirm recent studies of disconnection demonstrating that AHP is not limited to dysfunction of motor systems, but involves a much wider set of large-scale cortical networks.

中文翻译：

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偏瘫失认症的多重网络断开

偏瘫失认症 (AHP) 是一种复杂的综合征，其神经相关性仍在调查中。一种主要基于病变映射研究的假设是 AHP 反映了与运动功能相关的右半球神经系统的故障。然而，最近的理论表明，层次分析法可能代表了一种涉及信念更新、自我参照或身体加工的认知系统障碍。最近的两项研究，使用一种方法来估计白质与病变断开的程度，确实表明 AHP 患者遭受了关联皮层中几个长程白质通路的损伤。在这里，我们使用类似的间接断开方法来研究一组没有失认症（偏瘫或偏瘫，HP，n = 35）的运动障碍患者，或 AHP 的运动缺陷（n = 28）。HP 病变来自中风患者数据库，而 AHP 病例则选自已发表的文献。使用标准方法从出版物的插图中将病变追踪到图谱中。AHP 中没有比 HP 更严重的大脑区域。在结构连通性方面，AHP 患者与 HP 患者有相似的运动通路断开模式。然而，AHP 患者也表现出右侧颞顶叶交界处、右侧岛叶、右侧和内侧前额叶皮层的显着断开。这些相关皮质区域通过几个白质束连接，包括上纵束 III、弓状、额岛岛、额下纵和额斜。这些束连接不同认知网络的区域：默认、腹侧注意力和扣带盖。这些结果没有针对临床变量进行控制，因为伴随症状和其他身体表征障碍并不总是可用于协变量分析。总之，我们证实了最近关于断开连接的研究，表明 AHP 不仅限于运动系统功能障碍，还涉及更广泛的大规模皮质网络。