急性小脑性共剂失调临床诊断与治疗

对24例患急性小脑共剂失调的患儿进行临床诊断和临床治疗,达到预期的临床治疗效果.     

Differential roles of multiple adhesion molecules in cell migration: Granule cell migration in cerebellum

Summary The migration of cerebellar granule cells from the external granular layer to the internal granular layer is mediated by the radial Bergmann glial fiber. Recent works have shown that cell adhesion molecules, extra-cellular matrix proteins and proteolytic enzymes or their activators are involved in this process. Immuno-localization studies showed differential temporal and spatial expression patterns of different adhesion molecules, their isoforms, and post-translational modification during different stages of granule cell migration. Functional perturbation experiments using cerebellar explant cultures demonstrated that several adhesion molecules as well as plasminogen activator are involved in granule cell migration and are required in different stages. Other systems used to study granule cell migration including dissociated microwell cultures and granule cell deficient mouse mutants are discussed in the context of adhesion molecules. The results accumulated so far suggest that the migration of granule cells is a complex process in which the cooperation of a group of molecules with different functions, some for adhesion some for de-adhesion, are required to fulfill the different needs during the migratory course.     

内模原理在肢体平衡中的模型及应用

为了解决肢体平衡问题时可以保证系统在运动控制过程中的精确性和稳定性,该文在内模原理思想的基础上提出了一种基于预估器的小脑模型(KECFEL)。这种模型由前馈神经网络控制器构成;训练前馈模型中神经网络的教师信号由预估器以及反馈控制器(CFC)的输出来提供,并采用在线学习对网络进行权值更新与网络训练;同时采用比例微分控制器(PDC)作为反馈控制器以确保全局稳定性。通过该模型对倒立摆的仿真实验验证该模型对肢体平衡控制的有效性。     

时间加工的神经基础

时间是我们生存的基本维度,理解时间加工的神经基础对于感知觉、运动控制等领域有重要意义.本文通过综述相关研究总结了毫秒级和秒级时间加工的神经基础,从目前的研究成果来看,时间加工的神经基础是分布式的而非集中式的,主要在小脑、基底神经节和大脑皮层进行.目前还未有理论能统一解释时间加工的机制,未来研究还需深入对时间加工的机制的探讨.     

小脑中枢对血糖浓度的调节

通过去大脑家兔小脑内埋藏电极的慢性实验和去小脑的急性实验表明:在电流刺激小脑蚓部后可以引起血糖浓度升高;电刺激小脑的外侧部可以引起血糖浓度下降。证明小脑对血糖调节的部位是小脑蚓部和小脑外侧部;可以通过神经的作用控制胰岛素的分泌量。     

大鼠小脑特异基因Zic的克隆、序列分析和初步表达

EST（AW055732）片段是SD大鼠脑内一特异表达基因cDNA的3‘-端片段,与小鼠和人的Zic基因同源。基于小鼠及人的Zic基因的同源序列,设计引物用PCR方法从SD大鼠中克隆得到该基因的编码区序列（rZic)。该基因编码一锌指蛋白,其锌指结构域与线虫的tra-1基因,果蝇的ci^D基因。人的Gli癌基因和果蝇的opa基因的锌指结构域高度同源,用RT－PCR方法分析了rZic基因在大鼠脑区分布状况。结果表明,rZic基因在小脑中高表达。将该rZic基因克隆至带有6个组氨酸的表达载体pET-32a( )中,用IPTG诱导rZic融合蛋白在大肠杆菌BL21菌株中表达,诱导后重组蛋白质占菌体总蛋白的20．8％。     

慢性酒精中毒小鼠小脑的超微结构实验研究

目的 探讨慢性酒精中毒导致神经系统损伤的机制.方法 建立小鼠慢性酒精中毒动物模型,观察动物行为学的改变,测量血浆酒精浓度,通过透射电镜了解小脑的超微结构变化.结果 酒精处理组的血浆酒精浓度为101.4±20.5 mg/dL,与对照组和配对对照组比较,酒精处理组小鼠行动欠灵活,小脑线粒体形状多样、大小多变、数量增加和平均横断面面积显著减小;突触的数量减少、突触后膜致密物质厚度变薄、突触活性区长度变短及突触间隙宽度变宽,突触前结构内附着于突触的囊泡较多.结论 酒精对线粒体和突触结构、功能的损害可能是慢性酒精中毒的神经系统损伤机制之一.     

Cbln and C1q family proteins – New transneuronal cytokines

The C1q family is characterized by a C-terminal conserved global C1q domain, which is structurally very similar to the tumor necrosis factor homology domain. Although some C1q family members are expressed in the central nervous system, their functions have not been well characterized. Cbln1, a member of the Cbln subfamily of the C1q family, is predominantly expressed in cerebellar granule cells. Interestingly, Cbln1 was recently shown to play two unique roles at excitatory synapses formed between cerebellar granule cells and Purkinje cells: the formation and stabilization of synaptic contact, and the control of functional synaptic plasticity by regulating the postsynaptic endocytosis pathway. Since other Cbln subfamily members, Cbln2-Cbln4, are expressed in various regions of developing and mature brains, Cbln subfamily proteins may generally serve as a new class of transneuronal regulators of synapse development and synaptic plasticity in various brain regions.     

Effect of stress on choline acetyltransferase activity of the brain and the adrenal of the rat

Choline acetyltransferase (ChAT) activity was determined in cerebral cortex, hypothalamus, hippocampus, cerebellum, medulla oblongata, midbrain and adrenal gland of rats exposed to acute or chronic stress. The exposure of animals to acute immobilization and cold stress (4°C) for one hour resulted in a significant decline of ChAT activity in all brain regions examined except for the medulla oblongata. Moreover, the exposure to acute stress resulted in significant increase of the same enzyme in the adrenal gland. However, chronic exposure of animals to cold stress (4°C) for 7 days resulted in no significant changes of ChAT activity in all tissues examined except for a decline in the midbrain and an increase in the medulla oblongata. The administration of corticosterone (2.0 mg/kg) 1 h prior to sacrificing caused an effect similar to that of acute stress on ChAT activity in all brain regions except for the hypothalamus and the cerebellum. It was concluded from this experiment that stress-induced changes in the ChAT activity of specific brain regions might be mediated by the adrenal steroids.This work was supported by a grant from the National Aeronautics and Space Administration (NSG 2183 and NAG 2-411), a grant from the National Institutes of Health (NIH RR 0811) and a grant from the Division of Research Resources (NIH grant RR 03020).     

Involvement of the crebellum in sequential finger movement learning： Evidence from functional magnetic resonance imaging

Whether the cerebellum is involved in voluntary motor learning or motor performance is the subject of a new debate. Using functional magnetic resonance imaging （fMRI）, we examined cerebellar activation in eight voluntecrs before and after an extended period of training. Activation volume on both sides of cerebellum after learning was significantly reduced compared to that before learning even under the same motor frequency. Remarkably, while motor frequency for the training sequence was significantly higher than the control sequence after 41 d of learning, activation in the cerebellum for both sequences, with respect to activation loci and volumes, was very similar. These results suggest that the cerebellum was involved in motor learning but not motor performance. Changes of cerebellar activation from training thus appear to be associated with learning but not with improvement on task performance.