Orthographic processing is a critical stage in visual word recognition. However, the white-matter pathways that support this processing are unclear, as prior findings might have been confounded by impure behavioral measures, potential structural reorganization of the brain, and limited sample sizes. To address this issue, we investigated the correlations between the integrity of 20 major tracts in the whole brain and the pure orthographic index across 67 patients with short-term brain damage. The integrity of the tracts was measured by the lesion volume percentage and the mean fractional anisotropy value. The orthographic index was calculated as the residual of the orthographic tasks after regressing out corresponding nonorthographic tasks and the orthographic factor from the principal component analysis (PCA) on the basis of four orthographic tasks. We found significant correlations associated with the left inferior longitudinal fasciculus (ILF), even after controlling for the influence of potential confounding variables. These observations strengthen evidence for the vital role of the left ILF in orthographic processing.

中文翻译：

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左下纵束支持正字处理：来自病变行为映射分析的证据

正字法处理是视觉词识别的关键阶段。然而，支持这种处理的白质通路尚不清楚，因为先前的发现可能被不纯的行为测量、潜在的大脑结构重组和有限的样本量所混淆。为了解决这个问题，我们研究了 67 名短期脑损伤患者的全脑 20 个主要脑区的完整性与纯正字法指数之间的相关性。通过病变体积百分比和平均分数各向异性值测量束的完整性。正字索引计算为在四个正字任务的基础上从主成分分析 (PCA) 中回归出相应的非正字任务和正字因子后的正字任务的残差。我们发现与左下纵束 (ILF) 相关的显着相关性，即使在控制了潜在混杂变量的影响之后也是如此。这些观察结果加强了左侧 ILF 在正字法处理中的重要作用的证据。