Natbrainlab, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King's College London, London, UK.
Cereb Cortex. 2014 Mar;24(3):691-706. doi: 10.1093/cercor/bhs351. Epub 2012 Nov 15.
The exact anatomical localization of right hemisphere lesions that lead to left spatial neglect is still debated. The effect of confounding factors such as acute diaschisis and hypoperfusion, visual field defects, and lesion size may account for conflicting results that have been reported in the literature. Here, we present a comprehensive anatomical investigation of the gray- and white matter lesion correlates of left spatial neglect, which was run in a sample 58 patients with subacute or chronic vascular strokes in the territory of the right middle cerebral artery. Standard voxel-based correlates confirmed the role played by lesions in the posterior parietal cortex (supramarginal gyrus, angular gyrus, and temporal-parietal junction), in the frontal cortex (frontal eye field, middle and inferior frontal gyrus), and in the underlying parietal-frontal white matter. Using a new diffusion tensor imaging-based atlas of the human brain, we were able to run, for the first time, a detailed analysis of the lesion involvement of subcortical white matter pathways. The results of this analysis revealed that, among the different pathways linking parietal with frontal areas, damage to the second branch of the superior longitudinal fasciculus (SLF II) was the best predictor of left spatial neglect. The group study also revealed a subsample of patients with neglect due to focal lesion in the lateral-dorsal portion of the thalamus, which connects the premotor cortex with the inferior parietal lobule. The relevance of fronto-parietal disconnection was further supported by complete in vivo tractography dissection of white matter pathways in 2 patients, one with and the other without signs of neglect. These 2 patients were studied both in the acute phase and 1 year after stroke and were perfectly matched for age, handedness, stroke onset, lesion size, and for cortical lesion involvement. Taken together, the results of the present study support the hypothesis that anatomical disconnections leading to a functional breakdown of parietal-frontal networks are an important pathophysiological factor leading to chronic left spatial neglect. Here, we propose that different loci of SLF disconnection on the rostro-caudal axis can also be associated with disconnection of short-range white matter pathways within the frontal or parietal areas. Such different local disconnection patterns can play a role in the important clinical variability of the neglect syndrome.
导致左侧空间忽略的右侧大脑半球病变的确切解剖定位仍存在争议。混杂因素（如急性去传入和灌注不足、视野缺损和病变大小）的影响可能导致文献中报告的相互矛盾的结果。在这里，我们对 58 例右侧大脑中动脉区域亚急性或慢性血管性中风患者的灰质和白质病变相关性进行了全面的解剖学研究。标准体素基相关性证实了病变在后顶叶皮层（缘上回、角回和颞顶交界处）、额叶皮层（额眼区、中额和下额回）以及下顶叶-额叶白质中的作用。使用新的基于弥散张量成像的人脑图谱，我们首次能够对皮质下白质通路的病变累及进行详细分析。该分析的结果表明，在连接顶叶和额叶的不同通路中，损伤二级上纵束（SLF II）是预测左侧空间忽略的最佳指标。组研究还揭示了一小部分患者由于丘脑外侧-背侧部分的局灶性病变而导致忽略，该部位连接了运动前皮层和下顶叶。在前两个没有忽略迹象的患者的活体追踪术中对 2 名患者的白质通路进行了完全解剖，进一步支持了额顶叶断开的相关性。这 2 名患者在中风发作后 1 年进行了急性和慢性期研究，在年龄、利手、中风发作、病变大小和皮质病变受累方面完全匹配。综上所述，本研究的结果支持以下假设：导致顶叶-额叶网络功能崩溃的解剖分离是导致慢性左侧空间忽略的重要病理生理因素。在这里，我们提出，在头尾轴上的不同 SLF 断开位置也可能与额叶或顶叶区域内的短程白质通路的断开相关。这种不同的局部断开模式可以在忽略综合征的重要临床变异性中发挥作用。
