Primary progressive aphasia (PPA) is a clinical neurodegenerative syndrome with word finding problems as a core clinical symptom. Many aspects of word finding have been clarified in psycholinguistics using picture naming and a picture-word interference (PWI) paradigm, which emulates naming under contextual noise. However, little is known about how word finding depends on white-matter tract integrity, in particular, the atrophy of tracts located ventrally to the Sylvian fissure. To elucidate this question, we examined word finding in individuals with PPA and healthy controls employing PWI, tractography, and computer simulations using the WEAVER++ model of word finding. Twenty-three individuals with PPA and twenty healthy controls named pictures in two noise conditions. Mixed-effects modelling was performed on naming accuracy and reaction time (RT) and fixel-based tractography analyses were conducted to assess the relation between ventral white-matter integrity and naming performance. Naming RTs were longer for individuals with PPA compared to controls and, critically, individuals with PPA showed a larger noise effect compared to controls. Moreover, this difference in noise effect was differentially related to tract integrity. Whereas the noise effect did not depend much on tract integrity in controls, a lower tract integrity was related to a smaller noise effect in individuals with PPA. Computer simulations supported an explanation of this paradoxical finding in terms of reduced propagation of noise when tract integrity is low. By using multimodal analyses, our study indicates the significance of the ventral pathway for naming and the importance of RT measurement in the clinical assessment of PPA.

原发性进行性失语症（PPA）是一种临床神经退行性综合症，其以寻字问题为核心临床症状。心理语言学已经使用图片命名和图片词干扰（PWI）范式澄清了单词查找的许多方面，该范式干扰了上下文噪声下的命名。但是，关于单词查找如何依赖于白色物质的完整性，尤其是位于西尔维安裂缝腹侧的物质的萎缩，知之甚少。为了阐明这个问题，我们检查了PPA和健康对照者在PPA中的单词发现情况，运用了PWI，文字记录法以及使用WEAVER ++单词发现模型进行计算机模拟。有两个PPA的个人和二十三个健康对照的人在两种噪声条件下命名图片。在命名准确性和反应时间（RT）上进行了混合效应建模，并进行了基于Fixel的束线照相术分析，以评估腹侧白色物质完整性与命名性能之间的关系。与对照组相比，PPA个体的RT命名时间更长，而且至关重要的是，PPA个体显示出更大的噪声影响。而且，这种噪声影响的差异与道的完整性有不同的关系。尽管噪音影响在很大程度上不依赖于对照组的管道完整性，但较低的管道完整性与PPA患者的较小噪音影响有关。计算机仿真支持这种悖论性发现的解释，即当道完整性较低时，可以减少噪声的传播。通过使用多峰分析，