Brain Organization Underlying Language Processing: The Effect of Environmental

尽管孩子们学习语言表面上很容易，但在学习语言的过程中存在着惊人的个体差异。 特定元素的发展过程，包括词汇和句法知识，手势的使用， 阅读的习得。儿童之间的一个重要差异是他们所处的语言环境。 暴露，这对语言增长的速度和时间有重大影响。 在我们正在进行的纵向语言研究（LLS）中，我们已经表明，学前技能水平是 受到学前教育的影响。下一步是确定早期输入和技能与后来的关系。 成就及其神经机制。在口语和阅读中，我们都注重单词 解码和句子理解在听觉和拼写水平。我们研究这个 发育生物学在典型发育儿童和早期单侧脑损伤儿童中的应用。 我们组织我们的生物学研究围绕几个假定的处理途径，在成人 大脑，在儿童时期发展，并受到儿童环境的影响， 体验.这种模式将口语和阅读分为两个不同的部分，单词解码 和句子理解。在口头形式，字解码涉及两个流，一个占主导地位的 左侧偏侧的"背侧流"，将声音映射到发音代表上， 代表了“腹侧流”，将声音映射到词汇意义上。在书面形式中，单个单词 解码似乎也涉及两条通路，都相对偏左，包括一条"背侧通路"， 通过分解（字素-音素转换）机制和"腹侧路径"解码单词 使用直接视觉（词汇/语义）识别。句子理解的机制 相对独立于模态，由前颞和下额“前流”介导， 其将单词映射到句法级和语义级表示。 这些解码和理解系统的发展需要输入。我们假设 语音的发展，所需的听觉和书面文字解码，涉及发展， 顶叶和运动前区回路负责观察和模仿。书面文字的发展 解码似乎需要语音系统和专门的视觉过程之间的相互作用。 最后，理解系统的发展似乎依赖于照顾者语言的复杂性， 早期出现复杂的语言和手势。 总之，我们的目标是了解与口语和书面语相关的神经活动模式， 学龄儿童的语言理解能力，并描述早期学前语言的作用 和手势来决定这个神经网络架构的结构。

Despite the apparent ease with which children learn language, there are striking individual differences in time course of growth of particular elements, including lexical and syntactic knowledge, use of gesture, and acquisition of reading. An important difference among children is the linguistic environment to which they are exposed, and this has a significant effect on the rate and timing of language growth. In our ongoing Longitudinal Language Study (LLS), we have shown that preschool skill levels are affected by preschool input. The next step is to determine the relationship of early input and skill to later achievement and to their neural mechanisms. In both oral language and reading, we focus on word decoding and sentence comprehension at both the auditory and orthographic levels. We study this developmental biology both in typically developing children and those with early unilateral brain lesions. We organize our biological investigations around several putative processing pathways in the adult brain, which develop over the course of childhood, and which are affected by the child's environment and experience. This model divides both oral language and reading into two distinct components, word decoding and sentence comprehension. In the oral modality, word decoding involves two streams, a predominantly left lateralized "dorsal stream" that maps sound onto articulatory representations and a bilaterally represented "ventral stream" that maps sound onto lexical meaning. In the written modality, single word decoding also seems to involve two pathways, both relatively left lateralized, including a "dorsal route" that decodes words by a decompositional (grapheme-phoneme conversion) mechanism and a "ventral route" that uses direct visual (lexical/semantic) recognition. The mechanisms for sentence comprehension appear to be relatively modality independent, mediated by an anterior temporal and inferior frontal "anterior stream", which maps words into sentence-level syntactic and semantic representations. Development of these decoding and comprehension systems requires input. We hypothesize that phonological development, required for both auditory and written word decoding, involves development of parietal and premotor circuits for observation and execution through imitation. Development of written word decoding appears to require interaction between this phonological system and specialized visual processes. Finally, development of comprehension systems appears to rely on the complexity of caregiver speech, and the early presence of complex speech and gesture. In summary, we aim to understand the patterns of neural activity associated with oral and written language comprehension in school-age children, and to characterize the role of early preschool language and gesture in determining the structure of this neural network architecture.