Olivocerebellar Circuitry in Autism

描述(申请人提供)：自闭症患者有明显的运动障碍 有特征性的低眼压和运动规划困难(Bauman，1999) 自闭症大脑的关键神经病理学研究报告了选择性 多种边缘系统结构和结构中的细胞改变 在橄榄球小脑的连接中。在大脑后外侧半球 小脑皮质、浦肯野细胞(PC)数量明显减少， 下橄榄核(IO)和中缝大核(IO)也有细胞变化。 小脑核团(CN)，后者显示成人的细胞丢失。引航员 对4名自闭症患者和3名对照组的海马区研究表明， 仅在GABA能受体系统中有统计学意义的差异 (苯二氮平结合位点和GABAA受体)首次标记 这种中枢效应在自闭症患者的GABA系统中很明显。摄动 在自闭症患者小脑的GABA系统中也很明显 PC缺陷和一些成年CN细胞的丢失但本质上的干扰 还没有得到解决。这项提案的长期目标是确定 通过现代方法，这些GABA能主要靶点的缺失如何 橄榄小脑攀升纤维(CFs)影响大鼠小脑环路 自闭症患者的大脑及其是否造成谷氨酸能神经元的“错配” IO-PC和I0-CN连接和/或GABA能PC-CN和CN-IO电路。至 为此，我们将使用(1)免疫细胞化学来确定 CFS的分布：并获得对CFS时机的宝贵量化见解 (2)原位杂交法研究PC的表达和水平。 合成GABA的关键酶(谷氨酸脱羧酶或 Gad)；两种钙结合蛋白与PC的共定位 PC中的GAD和细胞中关键的GABA能转运体(GAT-1-3)的表达 和(3)定量受体放射自显影以定位任何 三种类型GABA能分子密度和/或结合亲和力的变化 小脑皮质、CN和IO的受体。数据将与 神经病理改变和每个自闭症病例的临床资料 根据传入-目标-传出连接进行解释并观察到 每个感兴趣区域的细胞变化。这些研究的发现 希望能为早期干预的发展带来新的方向 针对自闭症患者，目的是改善 受影响的个体。

DESCRIPTION (provided by applicant): Motor dysfunction is evident in autism with characteristic hypotonia and motor planning difficulties (Bauman, 1999) Key neuropathological studies in autistic brains have reported selective cellular alterations in a variety of limbic system structures and in structures within olivocerebellar connectivity. In the posterolateral hemisphere of the cerebella cortex, Purkinje cells (PCs) were markedly reduced in number and cellular changes were also found in the inferior olivary nuclei (IO) and cerebellar nuclei (CN) with the latter showing cell loss in adults. Pilot studies in the hippocampus of 4 autistics and 3 controls, have shown statistically significant differences only in the GABAergic receptor system (both benzodiazpine binding sites and GABAA receptors) marking the first time that central effect were evident in the GABA system of autistics. Perturbations in the GABA system in the cerebellum of autistics are also evident due to the PC deficit and a loss of some adult CN cells but the nature of the disturbances has not been addressed. The long term goal of this proposal is to determine through modern methods, how the absence of these GABAergic primary targets of olivocerebellar climbing fibers (CFs) affects cerebellar circuitry in the autistic brain and whether this creates a "miswiring" of the glutamatergic IO-PC and I0-CN connectivity and/or the GABAergic PC-CN and CN-IO circuitry. To accomplish this, we will use (1) immunocytochemistry to determine the distribution of CFs: and gain valuable quantitative insights into the timing of the PC loss; (2) in situ hybridization to study the levels and expression of two isoforms of a key enzyme for GABA synthesis (glutamate decarboxylase or GAD) in PCs; the co localization of two types of calcium binding proteins with GAD in PCs; and the expression of key GABAergic transporters (GAT-1-3) in cells of the CN and (3) quantitative receptor autoradiography to localize any alterations in the density, and/or binding affinity of three types of GABAergic receptors in the cerebellar cortex, CN and IO. Data will be compared to neuropathological changes and to clinical data from each autistic case and interpreted based on afferent-target-efferent connectivity and observed cellular changes in each region of interest. Findings from these studies hopefully will lead to new directions for the development of early intervention for autistic individuals with an aim to improve the quality of life for affected individuals.