Department of Clinical Psychology and Psychobiology, University of Barcelona, Pg. Vall d'Hebron 171, 08035, Barcelona, Catalonia, Spain.
Department of Psychiatry and Legal Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain.
Brain Imaging Behav. 2021 Aug;15(4):2109-2120. doi: 10.1007/s11682-020-00406-3. Epub 2020 Oct 13.
The link between literacy difficulties and brain alterations has been described in depth. Resting-state fMRI (rs-fMRI) has been successfully applied to the study of intrinsic functional connectivity (iFc) both in dyslexia and typically developing children. Most related studies have focused on the stages from late childhood into adulthood using a seed to voxel approach. Our study analyzes iFc in an early childhood sample using the multivariate pattern analysis. This facilitates a hypothesis-free analysis and the possible identification of abnormal functional connectivity patterns at a whole brain level. Thirty-four children with literacy difficulties (LD) (7.1 ± 0.69 yr.) and 30 typically developing children (TD) (7.43 ± 0.52 yr.) were selected. Functional brain connectivity was measured using an rs-fMRI acquisition. The LD group showed a higher iFc between the right middle frontal gyrus (rMFG) and the default mode network (DMN) regions, and a lower iFc between the rMFG and both the bilateral insular cortex and the supramarginal gyrus. These results are interpreted as a DMN on/off routine malfunction in the LD group, which suggests an alteration of the task control network regulating DMN activity. In the LD group, the posterior cingulate cortex also showed a lower iFc with both the middle temporal poles and the fusiform gyrus. This could be interpreted as a failure in the integration of information between brain regions that facilitate reading. Our results show that children with literacy difficulties have an altered functional connectivity in their reading and attentional networks at the beginning of the literacy acquisition. Future studies should evaluate whether or not these alterations could indicate a risk of developing dyslexia.
读写困难与大脑改变之间的联系已被深入描述。静息态 fMRI(rs-fMRI) 已成功应用于阅读障碍和正常发育儿童的内在功能连接(iFc)研究。大多数相关研究都集中在使用种子到体素方法的从儿童晚期到成年期的阶段。我们的研究使用多变量模式分析分析了早期儿童样本中的 iFc。这便于进行无假设分析，并有可能在全脑水平上识别异常的功能连接模式。选择了 34 名有读写困难（LD）的儿童（7.1±0.69 岁）和 30 名正常发育的儿童（TD）（7.43±0.52 岁）。使用 rs-fMRI 采集来测量功能大脑连接。LD 组显示右额中回（rMFG）和默认模式网络（DMN）区域之间的 iFc 较高，rMFG 与双侧岛叶皮层和缘上回之间的 iFc 较低。这些结果被解释为 LD 组的 DMN 开/关常规功能障碍，这表明调节 DMN 活动的任务控制网络发生了改变。在 LD 组中，后扣带回皮层与中颞极和梭状回之间的 iFc 也较低。这可以解释为促进阅读的大脑区域之间的信息整合失败。我们的研究结果表明，在开始识字阶段，读写困难的儿童在阅读和注意力网络中存在功能连接改变。未来的研究应该评估这些改变是否可以指示发展阅读障碍的风险。
