BRAIN ASYMMETRY AND LANGUAGE DEVELOPMENT

人脑在功能和解剖学上都是偏侧的。 在大多数 成年人，语言是本地化的左半球，而空间和 情绪功能位于右半球。 向左 颞平面（韦尼克区）和三角部不对称 （布罗卡区）被认为是神经生物学基质， 功能性偏侧化 在儿童时期， 变得不可逆转。 40名正常儿童的初步数据表明， 大脑不对称的发育变化发生在这一时期。 本项目旨在确认这些变化，并探讨 不对称性和语言技能的发展之间的关系。 这项研究将 提供正常大脑形态测量的数据库， 在儿童的磁共振成像（MRI）扫描中可视化 在5到10岁之间。 主要目标是确定 是否（1）前后语言的体积不对称 区域在此期间发生变化;（2）平面不对称性预测技能， 音位意识、阅读和拼写;（3）三角部 不对称性预示着表达性口语和流利性的技能。 在 此外，结构的体积变化不被认为是主要的 参与语言发展的胼胝体尾状核 和海马体，将被测量以检查 调查结果。 一组100名受试者，年龄5岁6个月至7岁6个月， 正常智商，将给予语言历史问卷和 神经语言学成套测验，包括音素意识、阅读和 口头语言 受试者组将在性别和利手方面保持平衡。 受试者将接受头部MRI扫描， 一系列薄的矢状切片。 基于计算机的体积测量 将由韦尼克区的颞平面三角部组成 在布洛卡区海马体和尾状核 十字架- 躯干的腹侧、体部、峡部和压部的截面积 还将测量胼胝体和总颅内体积。 两年后，这些孩子将再次接受测试和扫描。 基于 以前的工作以及试点数据预测（1），增加 颞平面的不对称性将伴随着发育 音素意识、阅读和拼写的改善;（2）右旋 儿童三角部的左侧不对称性比 （3）具有良好表达能力的儿童， 三角部不对称。 这些结果应该有助于了解 儿童期正常语言发育的神经基质， 一个正常的数据库， 和学习障碍的儿童。 这些数据还将使 精确映射语言区域，以与EEG和其他 儿童功能研究。

The human brain is functionally and anatomically lateralized. In most adults, language is localized in the left hemisphere while spatial and emotional functions are localized in the right hemisphere. Leftward asymmetry of the planum temporale (Wernicke's area) and pars triangularis (Broca's area) are believed to be the neurobiological substrate of this functional lateralization. During childhood, functional lateralization becomes irreversible. Pilot data in 40 normal children suggest that developmental changes in cerebral asymmetry occur during this period. This project seeks to confirm those changes and to explore the relation between asymmetry and the development of language skills. The study will provide a data base of measurements of normal cerebral morphology as visualized in the magnetic resonance imaging (MRI) scans of children between the ages of 5 and 10. The major objectives are to determine whether (1) volumetric asymmetries of the anterior and posterior language regions change during this period; (2) planar asymmetry predicts skill in phonemic awareness, reading and spelling; and (3) pars triangularis asymmetry predicts skills in expressive oral language and fluency. In addition, volumetric changes in structures not thought to be primarily involved in language development -- the corpus callosum, caudate nucleus and the hippocampus, will be measured to examine the specificity of the findings. A group of 100 subjects, aged 5 years 6 months to 7 years 6 months, with normal IQs, will be given a language history questionnaire and a neurolinguistic battery including tests of phonemic awareness, reading and oral language. The subject group will be balanced for sex and handedness. The subjects will receive MRI scan of the head that provides a gapless series of thin sagittal sections. Computer based volumetric measurements will be made of the planum temporale in Wernicke's area, pars triangularis in Broca's area, the hippocampus, and the caudate nucleus. The cross- sectional area of the genu, body, isthmus, and splenium of the corpus callosum and the total intracranial volume will also be measured. The children will be tested and scanned again two years later. Based on previous work as well as pilot data it is predicted (1) that increases in leftward asymmetry of the planum temporale will accompany developmental improvements in phonemic awareness, reading and spelling; (2) dextral children will have greater leftward asymmetry of pars triangularis than adextrals; (3) children with good expressive skills will have greater asymmetry of pars triangularis. The results should shed light on the neuronal substrate of normal language development in childhood and provide a normal database from which comparisons to brain structures in language and learning impaired children can be made. The data will also enable the accurate mapping of language areas for correlation with EEG and other functional studies in children.