Multiple climbing fiber innervation of Purkinje cells in the adult cerebellum

成人小脑浦肯野细胞的多重攀爬纤维神经支配

• 批准号: 10315621
• 负责人: Christian Robert Hansel
• 金额: $ 45.1万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2023-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10315621
• 关键词: Address; Adult; Age; Anatomy; Animals; Architecture; Auditory; Behavioral; Brain; Calcium; Calcium Signaling; Cells; Cerebellum; Characteristics; Complex; Confocal Microscopy; Contralateral; Data; Dendrites; Development; Dyes; Electrophysiology (science); Elements; Evolution; Excitatory Synapse; Exposure to; Female; Fiber; Flowcharts; Fluorescent Dyes; Frequencies; Funding; Goals; Image; In Vitro; Individual; Inferior; Injections; Instruction; Investigation; Knowledge; Label; Laboratories; Learning; Location; Measures; Methodology; Microscopic; Minority; Modality; Morphology; Motor; Mus; Neurons; Olives - dietary; Output; Pattern; Physiology; Pilot Projects; Play; Population; Purkinje Cells; Qualifying; Research; Rewards; Rodent; Role; Sensory; Signal Transduction; Slice; Stains; Stimulus; Subgroup; Synapses; Tactile; Testing; Tracer; Visual; awake; base; cognitive function; in vivo; male; motor control; motor learning; nerve supply; neuronal cell body; operation; patch clamp; response; sensory stimulus; sex; supervised learning; theories; two-photon

The architecture of brain circuits plays an essential role in understanding their function. The discovery of principal concepts in physiology and neurocomputation critically depends on the availability of precise morphological knowledge. A prominent example supporting this notion is the cerebellum, a brain circuit that is involved in motor (and non-motor) control and adaptation. At the center of cerebellar circuits are Purkinje cells, projection neurons that receive thousands of excitatory synapses, which convey sensory information needed for proper motor control. A hallmark feature of these unique neurons is that they have a massive dendrite that is innervated, in the adult brain, by one climbing fiber input. The climbing fiber plays a crucial role in theories of cerebellar supervised learning, and within this conceptual framework provides an instructive signal (here an error signal) guiding plasticity at parallel fiber synapses. More recent studies have, in addition, pointed out roles in reward signaling and noted that climbing fiber-evoked complex spikes occur in response to a variety of sensory stimuli and may also carry motor command signals. These activity-dependent complex spikes are observed in addition to spontaneous complex spikes that occur at an average frequency of about 1Hz. Thus, while we do not know what the exact functions of climbing fiber signaling are, it is obvious that this unusual input provides a core element of cerebellar cortical circuits and to some degree will define its operations. Our discovery – presented here as pilot data – that a subgroup of the entire adult Purkinje cell population (~15%) has two climbing fiber inputs instead of just one, that two inputs are almost exclusively observed in Purkinje cells with two primary dendrites (either separately exiting from the soma, or separating in close proximity to it) and that within this subgroup 20-25% of Purkinje cells show two climbing fiber inputs, leads to the question whether there is a functional significance of this double innervation. Is persistent double climbing fiber innervation of adult Purkinje cells a bug or a feature? In this exploratory study, we plan to examine the basic phenomenon further and to assess whether two separate climbing fiber inputs may signal independently. If the answer to our ‘bug or feature’ question is ‘feature’, we will examine consequences for cerebellar function (e.g. behavioral learning tests) in subsequent studies that we will seek separate funding for. The first aim uses patch-clamp recordings from mice in combination with confocal microscopy in vitro to test the hypothesis that the persistence of multiple climbing fibers is not random, but occurs in Purkinje cells with two primary dendrites. We will also inject tracer dyes into the inferior olive to stain climbing fibers and anatomically confirm the existence of two climbing fiber inputs. The second aim will add calcium imaging in vitro to examine whether a double climbing fiber input leads to functionally separate, dendritic calcium signaling domains. The third aim uses GCaMP6f-based two-photon imaging from Purkinje cells in awake mice to assess whether under spontaneous conditions, or with sensory stimulation, two climbing fiber inputs may operate independently.

大脑电路的结构在理解其功能中起着至关重要的作用。发现 生理学和神经体现的主要概念在很大程度上取决于精度的可用性 形态学知识。支持这个概念的一个突出的例子是小脑，一个大脑电路 参与电动机（和非运动）控制和适应。在小脑电路的中心是浦肯野细胞， 投影神经元接收数千个兴奋性突触，这些突触传达所需的感官信息 为了适当的电动机控制。这些独特的神经元的标志性特征是它们具有巨大的树突 通过一个攀岩纤维输入来支配成人大脑。攀岩纤维在理论中起着至关重要的作用 小脑监督学习，在此概念框架中，有一个有启发性的信号（这里是 错误信号）指导可塑性在平行纤维突触下。此外，最近的研究指出了 在奖励信号传导中的作用，并指出攀爬纤维诱发的复合峰响应于多种 感官刺激，也可能带有电动机命令信号。这些与活动有关的复合峰值是 除了在平均频率约为1Hz的平均频率下观察到的峰值。那， 虽然我们不知道攀登光纤信号的确切功能是什么，但很明显这种不寻常的 输入提供了小脑皮质电路的核心元素，并在某种程度上定义了其操作。我们的 发现 - 在这里作为试验数据呈现 - 整个成年浦肯野的亚组（〜15％） 有两个攀登纤维输入，而不仅仅是一个，几乎可以在Purkinje中观察到两个输入 具有两个主要树突的细胞（分别从躯体退出，或与之近距离分离） 在该亚组中，有20-25％的浦肯野细胞显示出两个攀岩纤维输入，这导致了问题 这种双重神经是否具有功能意义。是持续的双攀爬纤维 成年浦肯野细胞的神经或特征？在这项探索性研究中，我们计划检查 进一步的基本现象，并评估两个单独的攀岩纤维输入是否可以独立发出信号。 如果我们的“错误或功能”问题的答案是“功能”，我们​​将检查小脑功能的后果 （例如，行为学习测试）在随后的研究中，我们将寻求单独的资金。第一个目的使用 来自小鼠的斑块钳记录与共聚焦显微镜在体外结合使用，以检验以下假设。 多个攀爬纤维的持久性不是随机的，而是在两个主要的珀肯吉细胞中 树突。我们还将将示踪剂染料注入下橄榄，以降污纤维并在解剖学上确认 存在两个攀登纤维输入。第二个目标将在体外增加钙成像，以检查是否是否 双攀爬纤维输入导致功能分开的树突状钙信号传导域。第三个目标 使用来自呼吸小鼠的Purkinje细胞的基于GCAMP6F的两光子成像来评估是否在 赞助条件或有感觉刺激，两个攀岩纤维输入可能独立运行。