Interactive Specialization in Language Impairment

描述(申请人提供)：这个项目将使用功能磁共振成像(FMRI)来研究语言发展的神经基础。在纵向设计中，幼儿将被给予单词水平和句子水平的任务，这些任务涉及语音、语义和形态句法加工。我们假设，通过增加与额叶皮质的相互作用(即连接性)，在不同的语言表征方面，颞顶叶皮质在发育过程中变得更加专业化。专门化的特征应该是颞顶皮质对涉及语言功能不同方面的任务的差异反应增加。该项目将测试交互式专业化认证 明确预测大脑发育差异的模型[1，2]，但几乎没有直接性 神经成像证据支持它[19]。这个模型的中心原则是，大脑区域之间的相互作用推动了进行某些计算的大脑区域的专门化。互动-特化模型的扩展预测，LI儿童应该在颞顶皮质缺乏专门化，这可能是由于颞顶和额叶区域之间的交互作用改变所致。大脑区域之间的功能连接将通过心理生理相互作用(PPI)来衡量，专业化将通过激活差异来衡量，但也将通过代表性相似性分析(RSA)来衡量。考察从学龄前到小学的语言发展是很重要的，因为这一过渡的标志是掌握了复杂的形态句法原则，对语义表征进行了细化和提炼，并提高了儿童处理音素信息的能力。检验我们最重要的假设的核心是量化幼儿的大脑变化，以及语言障碍(LI)中出现的差异。以前的功能磁共振研究一般使用横断面设计，只检查了一个年龄组，检查了广泛的年龄范围(即从幼儿园到青春期)和/或没有检查多个语言过程。此外，只有少数几项神经成像研究检查了儿童LI的大脑基础。我们的项目将通过使用纵向方法来研究幼儿多种语言过程的发展，从而克服这些缺点。在发育神经成像文献中很少使用纵向方法，但对于深入了解是什么机制驱动语言发展至关重要。我们项目的一个重要优势是使用理论上有动机的实验任务，基于广泛的行为文学来调查关于幼儿大脑发育的创新想法。使用复杂的变化模型还将使我们能够确定语言障碍的纵向增长是否代表了数量和质量的差异，以及神经成像指标是否可以唯一地预测那些可能在语言处理方面进一步落后的儿童。

DESCRIPTION (provided by applicant): This project will examine the neural basis of language development using functional magnetic resonance imaging (fMRI). In a longitudinal design, young children will be given word level and sentence level tasks that tap into phonological, semantic and morpho-syntactic processing. We hypothesize that temporo-parietal cortex becomes more specialized over development for distinct linguistic representations through increasing interaction (i.e. connectivity) with frontal cortex. Specialization should be characterized by increases in differential responses in temporo-parietal cortex to tasks tapping into distinct aspects of linguistic function. This project will test the interactive-specialization model that makes clear predictions of developmental brain differences [1, 2], but has little direct neuroimaging evidence to support it [19]. The central tenet of this model is that interaction between brain regions drives the specialization of brain regions for making certain computations. An extension of the interactive-specialization model predicts that children with LI should have lack of specialization in temporo-parietal cortex perhaps due to altered interaction between temporo-parietal and frontal regions. Functional connectivity between brain regions will be measured with Psychophysiological Interaction (PPI) and specialization will be measured with activation differences, but also with Representational Similarity Analysis (RSA). Examination of language development in the transition from preschool to elementary school is important because this transition is marked by mastery of complex morpho-syntactic principles, elaboration and refinement of semantic representations, and by increases in children's ability to process phonemic information. Central to testing our overarching hypothesis is quantifying brain changes in young children, and differences that emerge in language impairment (LI). Previous fMRI studies have generally used cross-sectional designs and have only examined one age group, have examined a wide age range (i.e. from kindergarten through adolescence) and/or have not examined multiple linguistic processes. Moreover, only a handful of neuroimaging studies have examined the brain basis of LI in children. Our project will overcome these shortcomings by using a longitudinal approach to examine the development of multiple linguistic processes in young children. Longitudinal approaches are rarely used in the developmental neuroimaging literature, but are crucial for gaining insights into what mechanisms drive language development. A significant strength of our project is the use of theoretically motivated experimental tasks based on extensive behavioral literature to investigate innovative ideas regarding brain development in young children. The use of sophisticated change models will also allow us to determine whether the longitudinal growth in language impairment represents a quantitative versus qualitative difference and whether neuroimaging measures can be used to uniquely predict those children who are likely to fall further behind in language processing.