BRAIN DEVELPMENT IN AUTISM

我们实验室之前的研究表明，与发育迟缓（DD）和典型发育（ID）的同龄儿童相比，3-4岁的自闭症谱系障碍（ASD）儿童大脑增大，皮质下区域（小脑、海马和杏仁核）也相应增大。患有严格定义的自闭症（AD）的儿童表现出杏仁核的扩大，超过了整个大脑的扩大。在同一组儿童中，质子回声平面光谱成像（PEPSI）显示，与对照组相比，ASD儿童的脑神经化学物质浓度普遍区域下降，代谢物松弛异常，表明细胞组成异常。这些发现表明自闭症患者在3-4岁时出现了异常的大脑发育过程。在拟议的starart中心研究中，我们的目标是通过对AD儿童进行脑成像研究，增加我们对早期大脑发育异常的理解，目前可以诊断这种疾病。我们拟对48名18-24个月大的AD患儿和25名DD和TD患儿的匹配对照组进行脑结构和基于组织的神经化学表征。在AD组中，我们将把18-24个月时的大脑结构和化学发现与18-24个月及4岁后的神经认知和症状测量联系起来。

Previous work in our laboratory demonstrated that 3-4 year-old children with autism spectrum disorder (ASD) have cerebral enlargement, as well as proportional enlargement of subcortical regions (cerebellum, hippocampi and amygdalae), compared to age-matched children with developmental delay (DD) and typical development (ID). Children with strictly defined autistic disorder (AD) showed enlargement of the amygdalae, in excess of overall cerebral enlargement. From the same groups of children, proton echoplanar spectroscopic imaging (PEPSI) revealed widespread regional decreases in brain neurochemical concentrations and abnormal metabolite relaxation in the ASD children relative to controls, indicative of abnormal celluiar composition. These findings demonstrate abnormal brain developmental processes in autism by 3-4 years of age. In the proposed STAART Center research, we aim to increase our understanding of abnormalities in early brain development by conducting brain imaging research with children with AD at the earliest age it is currently possible to diagnose this disorder. We propose to characterize brain structure and tissue-based neurochemistry in forty-eight 18-24 month-old children with AD and matched comparison groups of 25 children with DD and TD. In the AD group, we will relate brain structural and chemical findings taken at 18-24 months to neurocognitive and symptom measures taken at 18-24 months and later at 4 years of age. Furthermore, based on repeated measures of head circumference obtained retrospectively from birth to 18-24 months, and prospectively from 18-24 month to 4 years, the early developmental course of head growth in autism will be examined.