Cognitive Brain Research Unit, Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Finland; School of Health and Rehabilitation Sciences, Queensland Aphasia Research Centre and UQ Centre for Clinical Research, The University of Queensland, Australia.
Cognitive Brain Research Unit, Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Finland.
Neuroimage. 2021 Nov 1;241:118411. doi: 10.1016/j.neuroimage.2021.118411. Epub 2021 Jul 20.
Current views on the neural network subserving reading and its deficits in dyslexia rely largely on evidence derived from functional neuroimaging studies. However, understanding the structural organization of reading and its aberrations in dyslexia requires a hodological approach, studies of which have not provided consistent findings. Here, we adopted a whole brain hodological approach and investigated relationships between structural white matter connectivity and reading skills and phonological processing in a cross-sectional study of 44 adults using individual local connectome matrix from diffusion MRI data. Moreover, we performed quantitative anisotropy aided differential tractography to uncover structural white matter anomalies in dyslexia (23 dyslexics and 21 matched controls) and their correlation to reading-related skills. The connectometry analyses indicated that reading skills and phonological processing were both associated with corpus callosum (tapetum), forceps major and minor, as well as cerebellum bilaterally. Furthermore, the left dorsal and right thalamic pathways were associated with phonological processing. Differential tractography analyses revealed structural white matter anomalies in dyslexics in the left ventral route and bilaterally in the dorsal route compared to the controls. Connectivity deficits were also observed in the corpus callosum, forceps major, vertical occipital fasciculus and corticostriatal and thalamic pathways. Altered structural connectivity in the observed differential tractography results correlated with poor reading skills and phonological processing. Using a hodological approach, the current study provides novel evidence for the extent of the reading-related connectome and its aberrations in dyslexia. The results conform current functional neuroanatomical models of reading and developmental dyslexia but provide novel network-level and tract-level evidence on structural connectivity anomalies in dyslexia, including the vertical occipital fasciculus.
目前关于阅读的神经网络及其在阅读障碍中的缺陷的观点在很大程度上依赖于功能神经影像学研究的证据。然而，理解阅读的结构组织及其在阅读障碍中的异常需要一种束路追踪方法，而这些研究并没有提供一致的发现。在这里，我们采用了全脑束路追踪方法，通过对 44 名成年人进行横断面研究，利用扩散 MRI 数据的个体局部连接矩阵，研究了结构白质连接与阅读技能和语音处理之间的关系。此外，我们还进行了定量各向异性辅助差异束追踪，以揭示阅读障碍（23 名阅读障碍者和 21 名匹配对照者）中的结构白质异常及其与阅读相关技能的相关性。连接分析表明，阅读技能和语音处理都与胼胝体（tapetum）、内囊前肢和后肢以及双侧小脑有关。此外，左背侧和右丘脑通路与语音处理有关。差异束追踪分析显示，与对照组相比，阅读障碍者在左侧腹侧通路和双侧背侧通路中存在结构白质异常。在胼胝体、内囊前肢、垂直枕状束和皮质纹状体及丘脑通路上也观察到连接缺陷。观察到的差异束追踪结果中的结构连接缺陷与阅读技能和语音处理较差相关。使用束路追踪方法，本研究为阅读相关连接组及其在阅读障碍中的异常提供了新的证据。结果符合当前阅读的功能神经解剖学模型和发展性阅读障碍，但提供了阅读障碍中结构连接异常的新的网络和束路水平证据，包括垂直枕状束。
