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

随着儿童学习阅读，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，主要涉及大脑的“阅读网络”--左半球的枕颞区、颞顶区和额区。阅读体验推动了视觉文字处理的功能神经专门化。到目前为止，经验在功能神经特化中的关键作用仍然没有得到检验，因为大多数研究只研究了有阅读经验的儿童阅读的神经发展轨迹--有阅读经验的儿童在政府规定的年龄(6岁)入学时开始接受正式识字指导。我们现有的研究大脑中阅读功能出现的方法不能分离经验和年龄的离散影响。一项重要的理论进步将是测试大脑的阅读网络是如何通过阅读经验或缺乏阅读经验而形成的。重新安置难民儿童为解决这些悬而未决的问题提供了机会。对于难民儿童来说，流离失所和移徙往往意味着学校教育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体验上的个体差异提供了一个“自然范式”，我们可以从中检验关于经验在视觉文字处理的功能神经专门化中的作用的具体假设。这项拟议的研究计划利用发展认知神经科学(功能神经成像)的最新工具，研究在不同年龄经历了不同时期的中断学校教育和恢复学校教育/学习阅读的儿童中，视觉文字处理神经系统的出现情况。我们的目标是研究叙利亚难民儿童的语言和视觉文字处理的神经基础，这些儿童经历了中断的学校教育，最近在加拿大重新定居，以及其他经历了连续教育的新来的儿童。第二，我们的目标是考察语音、词汇-语义和视觉文字加工的神经激活和功能连通性随阅读经验年龄的纵向变化，并检验随着时间的推移，纵向神经变化如何与儿童的阅读技能相对应。为了做到这一点，我们追踪了阿富汗难民儿童的神经激活和语言和视觉文字处理的功能连接，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。考察经验在阅读功能神经特化中的作用将提供重要的理论和实践见解--我们通过不同的发展经验对神经系统的发展有更深入的了解，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.