MEGALENCEPHALY IN AUTISM

我们实验室和其他实验室的结果都表明， 存在于14-26%的患有特发性自闭症的儿童和成人中。MRL 对脑重量的研究和死后研究表明， 孤独症中的大头畸形是由于巨脑畸形， 大脑。我们实验室的结果表明， 个体的头部大小，大脑的大小增加，由于 顶骨、颞叶和枕叶的体积增加（即， 后）叶。相对于整个大脑体积， 胼胝体不成比例地减少。其他数据表明， 皮质增大主要在右侧。MR研究， 其他中心也支持这些发现的有效性。 神经心理学和神经生物学证据表明， 是一个复杂的分布式神经网络的紊乱， 异常的大脑组织和连接的发现 自闭症患者的巨脑畸形表明， 也涉及增殖或程序性细胞死亡。整体 这个应用程序的目标是建立在我们以前的工作结构 通过探索大脑大小和形状的异常， 在患有巨脑畸形的自闭症患者中， 这些异常的发病机制的重要性， disorder.我们建议：1）检查异常的增长模式， 在患有巨脑畸形的自闭症患者中， （a）前后之间的关系异常 皮质脑体积，（B）皮质和胼胝体大小，（c）灰度 和白色物质体积，以及（d）右侧和左侧皮质叶 2）探索可能构成大脑的发育机制 通过检查头部变化的轨迹来扩大自闭症 周长随时间的变化; 3）检查综合征的异质性 通过探索大脑大小和形状之间的关系 与自闭症相关的临床特征的MRI异常 包括行为和神经心理学特征。

Results from both our laboratory and others indicate that macrocephaly is present in 14-26% of children and adults with idiopathic autism. MRl studies and post mortem studies of brain weight suggest that macrocephaly in autism is due to megalencephaly, abnormal enlargement of the brain. Results from our laboratory indicate that in autistic individuals unselected for head size, brain size is increased due to increased volume of the parietal, temporal and occipital (i.e., posterior) lobes. Relative to total brain volume the size of the corpus callosum is disproportionately decreased. Additional data suggest that cortical enlargement is predominantly right-sided. MR studies from other centers support the validity of these findings.- Neuropsychological and neurobiological evidence now suggest that autism is a disorder of a complex distributed neural network resulting in anomalous brain organization and connectivity. The finding of megalencephaly in autism suggests that abnormalities of cellular proliferation or programmed cell death are also involved. The overall goal of this application is to build on our previous work in structural imaging and genetics by exploring abnormalities in brain size and shape in autistic individuals with megalencephaly and by examining the significance of these abnormalities for the pathogenesis of this disorder. We propose to: 1) examine anomalous patterns of growth and organization in autistic individuals with megalencephaly as evidenced by abnormalities in the relationship between (a) anterior and posterior cortical brain volume, (b) cortical and corpus callosum size, (c) gray and white matter volume, and, (d) right- and left-sided cortical lobe volumes; 2) explore developmental mechanisms that may underlie brain enlargement in autism by examining the trajectory of changes in head circumference overtime; 3) examine heterogeneity in the syndrome of autism by exploring the relationship between brain size and shape abnormalities on MRI to clinical features associated with autism including behavioral and neuropsychological characteristics.