Elucidating the role of experience in the functional neural specialization for reading

当儿童学习阅读时，与视觉和语言处理相关的大脑区域形成了专门的皮质回路，主要涉及左半球的枕颞、颞顶和额叶区域--大脑的“阅读网络”。阅读经验驱动视觉文字处理的功能性神经特化。迄今为止，经验在功能性神经专业化中的关键作用尚未得到研究，因为大多数研究仅研究了具有阅读经验的儿童阅读的神经发育轨迹-当他们在政府规定的年龄（6岁）入学时开始正式识字教学的儿童。我们现有的研究大脑中阅读功能的方法无法将经验和年龄的离散效应分开。一个重要的理论进展将是测试大脑的阅读网络是如何通过阅读经验形成的，或者在整个发展过程中缺乏阅读经验。难民儿童的重新安置为解决这些悬而未决的问题提供了一个机会。对难民儿童来说，流离失所和移徙往往意味着一段时间的学业中断和阅读经验有限。随着不同年龄的难民儿童在加拿大重新定居，他们在学校学习一种新的语言并学习阅读。难民儿童在语言和阅读经验方面的个体差异提供了一个“自然范式”，从中我们可以检验关于视觉文字处理的功能性神经专门化中经验作用的具体假设。拟议的研究计划利用发展认知神经科学（功能性神经成像）的最新工具来研究视觉文字处理神经系统的出现，这些儿童经历了不同时期的中断学校教育，并在不同年龄恢复学校教育/学习阅读。我们的目标是研究语言和视觉文字处理的神经基础在叙利亚难民儿童谁经历了中断的学校教育和最近重新定居在加拿大，和其他新来的孩子谁经历了连续的学校教育。第二，我们的目标是检查纵向变化的神经激活和功能连接的语音，词汇语义和视觉文字处理的阅读经验的年龄的函数，并检查如何纵向神经变化对应于儿童的阅读技能随着时间的推移。为了做到这一点，我们跟踪了阿富汗难民儿童的语言和视觉文字处理的神经激活和功能连接，这些儿童经历了中断的学校教育，并将在未来两年抵达加拿大。研究经验在阅读功能性神经特化中的作用，将为我们提供重要的理论和实践启示，使我们更深入地了解神经系统在不同发展经验中的发展，以及神经系统在发展过程中不断变化的可塑性。

As children learn to read, brain regions associated with visual and language processing form specialized cortical circuits involving predominantly left-hemisphere occipitotemporal, temporoparietal, and frontal regions-the brain's `reading network'. Reading experience drives the functional neural specialization for visual word processing. To date, the critical role of experience in functional neural specialization has remained unexamined because most research has only examined neurodevelopmental trajectories for reading in children with reading experience-children who begin formal literacy instruction when they enroll in school at a government-mandated age (6 years). Our existing approaches to studying the emergence of reading function in the brain cannot separate the discrete effects of experience and age. An important theoretical advance would be to test how the brain's reading network forms through reading experience or lack thereof across development. The resettlement of refugee children provides an opportunity to address these outstanding issues. For refugee children, displacement and migration often corresponds to a period of interrupted schooling and limited reading experience. As refugee children of different ages resettle in Canada, they learn a new language and learn to read at school. Individual differences in language and reading experiences among refugee children provide a `natural paradigm' from which we can test specific hypotheses concerning the role of experience in functional neural specialization for visual word processing. The proposed research program leverages the latest tools of developmental cognitive neuroscience (functional neuroimaging) to examine the emergence of neural systems for visual word processing in children who have experienced variable periods of interrupted schooling and resumed schooling/learning to read at different ages. We aim to examine the neural bases for language and visual word processing in Syrian refugee children who've experienced interrupted schooling and recently resettled in Canada, and other newcomer children who've experienced continuous schooling. Second, we aim to examine longitudinal changes in neural activation and functional connectivity for phonological, lexical-semantic, and visual word processing as a function of age of reading experience, and examine how longitudinal neural changes correspond to children's reading skills over time. To do so, we track neural activation and functional connectivity for language and visual word processing in Afghan refugee children who've experienced interrupted schooling and who will arrive in Canada over the next two years. Examining the role of experience in the functional neural specialization for reading will provide important theoretical and practical insights-we gain a deeper understanding of the development of neural systems across diverse developmental experiences, and the changing plasticity of neural systems across development.