Neuronal plasticity and cerebellar circuitry

神经元可塑性和小脑回路

• 批准号: 7927776
• 负责人: NEAL H BARMACK
• 金额: $ 22.16万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7927776
• 关键词: Cells; Cerebellar Diseases; Cerebellum; Complex; Contralateral; Dendrites; Fiber; Golgi Apparatus; Inferior; Injection of therapeutic agent; Interneurons; Ipsilateral; Ketamine; Label; Labyrinth; Left; Measures; Medial Dorsal Nucleus; Mediating; Messenger RNA; Methods; MicroRNAs; Molecular; Mus; Neuronal Plasticity; Oligonucleotides; Olives - dietary; Output; Pathway interactions; Patients; Pattern; Phase; Physiological; Physiology; Proteins; Purkinje Cells; RNA Interference; Relative (related person); Research; Research Personnel; Role; Side; Signal Transduction; Speed; Stimulus; System; Techniques; Testing; Time; Viral Vector; Xylazine; adeno-associated viral vector; base; cell type; gamma-Aminobutyric Acid; granule cell; in vivo; knock-down; labyrinthectomy; metabotropic glutamate receptor 2; mossy fiber; neurobiotin; programs; promoter; receptor; research study; synthetic enzyme; theories; uvula; vector

DESCRIPTION (provided by applicant): In vivo analysis of cerebellar circuitry has focused almost exclusively on Purkinje cells, identified by their iconic patterns of complex and simple spikes (CSs and SSs). However, views of cerebellar function based exclusively on the physiology of Purkinje cells ignore the role of interneurons and distort the attributes of cerebellar afferent systems. It is universally assumed that SSs are modulated by the activity of the mossy fiber-granule cell-parallel fiber projection to Purkinje cell dendrites. In fact, during natural vestibular stimulation, vestibular primary afferent mossy fiber afferents discharge out of phase with the SSs recorded from nodular Purkinje cells. Consequently, it is unlikely that the cerebellar output signal merely reflects a gain-controlled version of the mossy fiber input signal. We proposed that SS modulation reflects the action of climbing fibers on cerebellar interneurons. We will test specific versions of this hypothesis by recording from identified interneurons. We have three objectives. First, we will record extracellularly from interneurons in the uvula-nodulus of anesthetized mice during natural vestibular stimulation. Interneurons will be labeled juxtacellularly with neurobiotin. The depth and phase of modulation of interneuronal discharge relative to that of Purkinje cell CSs and SSs will indicate which interneurons could modulate SSs. Second, we will study how the modulated activity of interneurons and Purkinje cells is altered by a unilateral labyrinthectomy (UL). Following a UL, the ipsilateral uvula-nodulus is accessible to vestibular information mediated only by climbing fibers whose modulation depends on the contralateral, intact labyrinth. Third, we will also make microlesions in the p-nucleus and dorsomedial cell column (dmcc) in the contralateral inferior olive. This will leave one side of the cerebellum accessible to vestibular information mediated only by vestibular mossy fibers. We will compare the effects of reduced vestibular signaling on interneurons and Purkinje cells. Fourth, we will microinject miRNAs in viral vectors with a cell specific promoter to selectively reduce expression of GABA-A alpha 1 receptors in nodular Purkinje cells. Fifth, we will also use miRNAs to selectively reduce synthesis of GABA in Golgi cells. We will analyze the effects of "knocking down" GABAergic signaling in these two cell types. We will characterize the stimulus-modulated functions of identified interneurons for the first time. We will interfere with cerebellar circuitry at a cellular level and test the role of interneurons in the modulation of SSs. The proposed research will speed application of molecular techniques to the treatment of patients with cerebellar disorders.

描述（由申请人提供）：小脑回路的体内分析几乎完全集中在浦肯野细胞上，通过其复杂和简单尖峰（CS和SS）的标志性模式进行鉴定。然而，小脑功能的观点完全基于浦肯野细胞的生理学，忽略了中间神经元的作用，并扭曲了小脑传入系统的属性。普遍认为，SS是由苔藓纤维颗粒细胞平行纤维投射到浦肯野细胞树突的活动调制。事实上，在自然前庭刺激，前庭初级传入苔藓纤维传入放电的相位与结节性浦肯野细胞记录的SS。因此，小脑输出信号不太可能仅仅反映苔藓纤维输入信号的增益控制版本。我们提出，SS调制反映了小脑中间神经元上的爬行纤维的行动。我们将通过记录识别出的中间神经元来测试这一假设的特定版本。我们有三个目标。首先，我们将记录在自然前庭刺激麻醉小鼠悬雍垂结节的中间神经元的细胞外。中间神经元将用神经生物素在细胞内标记。中间神经元放电的调制相对于浦肯野细胞CS和SS的深度和相位将指示哪些中间神经元可以调制SS。第二，我们将研究如何调制的活动的中间神经元和浦肯野细胞改变了单侧延髓切除术（UL）。UL后，同侧悬雍垂结节是访问前庭信息介导的攀爬纤维，其调制依赖于对侧，完整的迷路。第三，我们还将在对侧下橄榄核的p核和背内侧细胞柱（dmcc）中制作显微病变。这将使小脑的一侧只接受由前庭苔藓纤维介导的前庭信息。我们将比较前庭信号减少对中间神经元和浦肯野细胞的影响。第四，我们将在病毒载体中微量注射miRNA，并带有细胞特异性启动子，以选择性地降低结节性浦肯野细胞中GABA-A α 1受体的表达。第五，我们还将使用miRNAs选择性地减少高尔基体细胞中GABA的合成。我们将分析"敲低" GABA能信号在这两种细胞类型中的作用。我们将首次描述已识别的中间神经元的刺激调制功能。我们将在细胞水平上干扰小脑回路，并测试中间神经元在SS调制中的作用。这项拟议中的研究将加速分子技术在小脑疾病患者治疗中的应用。