Cognitive Neuroimaging Unit U992, INSERM, CEA DRF/Institut-Joliot/NeuroSpin, Université Paris-Saclay, Université Paris-Sud, 91191, Gif/Yvette, France.
Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, 75013, Paris, France.
Brain Struct Funct. 2019 May;224(4):1519-1536. doi: 10.1007/s00429-019-01855-3. Epub 2019 Mar 6.
Shortly after reading instruction, a region in the ventral occipital temporal cortex (vOTC) of the left hemisphere, the Visual Word Form Area (VWFA), becomes specialized for written words. Its reproducible location across scripts suggests important anatomical constraints, such as specific patterns of connectivity, notably to spoken language areas. Here, we explored the structural connectivity of the emerging VWFA in terms of its specificity relative to other ventral visual regions and its stability throughout the process of reading instruction in ten children studied longitudinally over 2 years. Category-specific regions for words, houses, faces, and tools were identified in the left vOTC of each subject with functional MRI. With diffusion MRI and tractography, we reconstructed the connections of these regions at two time points (mean age ± standard deviation: 6.2 ± 0.3, 7.2 ± 0.4 years). We first showed that the regions for each visual category harbor their own specific connectivity, all of which precede reading instruction and remain stable throughout development. The most specific connections of the VWFA were to the dorsal posterior parietal cortex. We then showed that microstructural changes in these connections correlated with improvements in reading scores over the first year of instruction but not 1 year later in a subsample of eight children (age: 8.4 ± 0.3 years). These results suggest that the VWFA location depends on its connectivity to distant regions, in particular, the left inferior parietal region which may play a crucial role in visual field maps and eye movement dynamics in addition to attentional control in letter-by-letter reading and disambiguation of mirror-letters during the first stages of learning to read.
在阅读说明后不久，左半球腹侧枕颞皮质（vOTC）中的一个区域，即视觉词形区（VWFA），开始专门处理书面文字。其在不同文字中的可重复位置表明存在重要的解剖学限制，例如特定的连接模式，特别是与口语语言区域的连接。在这里，我们从其相对于其他腹侧视觉区域的特异性以及在阅读教学过程中的稳定性两个方面，探讨了新兴 VWFA 的结构连接。在 10 名儿童中进行了为期 2 年的纵向研究，我们使用功能磁共振成像（fMRI）在每个被试者的左 vOTC 中识别出单词、房屋、面孔和工具的类别特异性区域。通过弥散磁共振成像（dMRI）和轨迹追踪，我们在两个时间点重建了这些区域的连接（平均年龄±标准差：6.2±0.3、7.2±0.4 岁）。我们首先表明，每个视觉类别区域都具有其自身特定的连接，所有这些连接都先于阅读教学，并且在整个发展过程中保持稳定。VWFA 最特异的连接是到背侧后顶叶皮层。然后我们表明，这些连接的微观结构变化与阅读分数在第一年教学中的提高相关，但在 8 名儿童的子样本中（年龄：8.4±0.3 岁）1 年后则没有相关性。这些结果表明，VWFA 的位置取决于其与远距离区域的连接，特别是左顶下小叶，它可能除了在逐字阅读和镜面对齐的识别中发挥注意力控制作用外，还在视觉场图和眼球运动动力学中发挥关键作用。
