MRI Imaging of the Corticostriatal and Hippocampal Systems in SLI

描述（由申请人提供）：皮质纹状体系统在特殊语言障碍（SLI）中的作用尽管语言习得在人类中几乎是普遍的，但有些人不如其他人熟练。语言习得不良是许多神经精神疾病的共同特征；然而，像特殊语言障碍（SLI）那样，没有明显原因的个体也可能出现语言发育不良。特殊语言障碍是一种常见的神经发育障碍，大约有7%到8%的学龄儿童患有这种疾病，并一直持续到成年。特殊语言障碍的病因不明；然而，基于新出现的行为证据，支持程序学习和强化学习的皮质纹状体系统可能至少部分地解释了特殊语言障碍的语言学习困难。目前，关于皮质纹状体系统，尤其是皮质下结构在特殊语言障碍中的作用的脑成像数据很少。因此，我们想知道是否有神经解剖学和神经功能证据表明，皮质纹状体系统对认知学习很重要，也有助于语言的个体差异。为了解决这个问题，该项目将跟踪最近一项实验性结构成像研究（SLI=12, Control=12）的发现，使用解剖磁共振成像（MRI）和扩散张量成像（DTI）来检查基底节区和丘脑的宏观结构和微观结构，这是皮质纹状体系统的主要皮层下组成部分。试验结果提供了强有力的证据（效应量> 0.8），表明各组间感兴趣区域的相对体积和分数各向异性（FA）存在差异。在这个拟议的项目中，我们将首先扩大试点结果，将样本量增加到每组35名参与者（特殊语言障碍，对照组），并将年龄范围扩大到青少年，因为青春期是大脑发生深刻变化的时期。然后，我们将通过扩散张量束图和静息状态功能MRI比较有和没有特殊语言障碍的青少年皮质纹状体环路的结构和功能连接。最后，我们将研究特殊语言障碍个体的脑-行为关系

DESCRIPTION (provided by applicant): The Role of the Corticostriatal System in Specific Language Impairment (SLI) Although the acquisition of language is nearly universal among humans, some are less adept than others. Poor acquisition of language is a common feature of many neuropsychiatric disorders; however, poor language development can occur in individuals who have no obvious causes as found in specific language impairment (SLI). SLI is a common neurodevelopmental disorder occurring in approximately 7 to 8% of school-age children that persists well into adulthood. The etiology of SLI is unknown; however, based on emerging behavioral evidence, the corticostriatal system that supports procedural and reinforcement learning may account for, at least in part, language learning difficulties in SLI. At this time, thre is little brain imaging data looking at the role of the corticostriatal system, subcortical structues in particular, in SLI. Thus, we have asked whether there is neuroanatomical and neurofunctional evidence showing that the corticostriatal system important to cognitive learning also contributes to individual differences in language. To address this question, the proposed project will follow up the findings from a recent pilot structural imaging study (SLI=12, Control=12) using anatomical magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to examine the macrostructure and the microstructure of the basal ganglia and the thalamus, which are the primary subcortical components of the corticostriatal system. The pilot results provided strong evidence (effect sizes > 0.8) of differences in the relative volume and fractional anisotropy (FA) of the regions of interest between groups. In this proposed project, we will first expand on the pilot findings by increasing the sample size up to 35 participants per group (SLI, control), and extend the age range to adolescents, given that adolescence is a time of profound brain change. Then, we will compare structural and functional connectivity in the corticostriatal loops between adolescents with and without SLI by using diffusion tensor tractography and resting-state functional MRI. Last, we will examine the brain-behavior relationship in individuals with SLI to enhance the translation of brain findings to clinical applications. We hypothesize that individuals with SLI will show macrostructural and microstructural abnormality in the basal ganglia (in particular the putamen and the nucleus accumbens based on our pilot findings) and the thalamus. In addition, individuals with SLI will show altered white matter organization of the corticostriatal loops as well as abnormal functional synchrony of the basal ganglia with the cortical regions. We also hypothesize that individuals with SLI will have poor performance on cognitive tasks that have been well established to involve the corticostriatal loops, and the brain measures will predict language status and cognitive learning performance. Completion of the aims will bring insights into the role of the corticostriatal system in SLI. The proposed project wll have a positive impact on the neural mechanisms underlying individual differences in language acquisition. 1