Organization of inhibition in the cerebellar cortex

小脑皮质的抑制组织

• 批准号: 10349928
• 负责人: Jason M Christie
• 金额: $ 122.92万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10349928
• 关键词: Organization; inhibition; cerebellar; cortex

Project Summary The project remains the same as the original application. Below is a summary overview. Our long-term goal is to generate a complete understanding of how the cerebellum learns to improve movement in response to motor errors. Climbing fibers are thought to play an essential role in this process because they fire during erroneous movement. Their activity reliably excites Purkinje cells, eliciting calcium spikes in their dendrites that can trigger long-term synaptic plasticity at coactive parallel fiber inputs. Plasticity induction ultimately leads to corrective behavior by altering the cerebellum's response to sensorimotor stimuli that predict mistakes. Importantly, inhibition from molecular layer interneurons (MLIs) that target Purkinje cell dendrites suppresses climbing-fiber-evoked calcium signaling, opposing or `gating' plasticity induction. Because MLIs are activated by movement, this suggests Purkinje cell disinhibition is required during motor learning. As MLIs inhibit other MLIs, their interconnections could support a circuit for Purkinje cell disinhibition during behavior. The objective of this proposal is to examine the possibility that MLI circuits are structured to support a context-dependent engagement that allows climbing fibers to instruct plasticity and learning in response to motor errors. To accomplish this, we will employ a multidisciplinary approach using cutting-edge molecular-genetic techniques, functional recordings, circuit mapping, and behavioral analysis. In the first aim, we will test whether ablating MLI-to-MLI connections that normally support Purkinje cell disinhibition affect the ability of climbing fibers to evoke full-blown calcium signals in response to motor errors, and whether loss of MLI-MLI circuit function affects cerebellar-dependent motor learning. In the second aim, we will establish an MLI taxonomy and use it to survey for previously unknown MLI subtypes. We will also use functional recordings to test whether there is evidence for bias connectivity within the MLI network that supports a dedicated circuit for Purkinje cell disinhibition. In the third aim, we will use anatomical tracing to ascertain the MLI connectome. In this way we will determine if there is a structural basis for the independent actuation of MLI subtypes through their afferent inputs and the cell-type selectivity of their efferent outputs. Completion of these aims will lead to an unprecedented understanding of the organizational logic of the molecular layer. In particular, we expect to reveal how circuits within the molecular layer control the induction of climbing-fiber- mediated learning. This knowledge will not only help develop theories/models of cerebellum function but will also provide insight into the processes underlying learning in general.

项目摘要 项目与原始应用程序相同。下面是一个概要概述。 我们的长期目标是对小脑如何学习改善产生完整的理解 运动错误的反应。攀缘纤维被认为在这一过程中起着至关重要的作用 因为它们会在错误的运动中开火它们的活性可靠地激发浦肯野细胞，引发钙 它们树突中的尖峰可以在相互作用的平行纤维输入时触发长期突触可塑性。可塑性 通过改变小脑对感觉运动刺激的反应，诱导最终导致纠正行为 可以预测错误。重要的是，来自靶向浦肯野细胞的分子层中间神经元（MLI）的抑制 树突抑制攀爬纤维诱发的钙信号传导，对抗或“门控”可塑性诱导。 由于MLI是由运动激活的，这表明浦肯野细胞在运动过程中需要解除抑制， 学习由于MLI抑制其他MLI，它们的相互连接可以支持浦肯野细胞去抑制的回路 在行为上。本建议的目的是研究MLI电路结构的可能性， 支持上下文相关的参与，允许攀爬纤维指导可塑性和学习， 对运动错误的反应。为了实现这一目标，我们将采用多学科的方法， 分子遗传学技术、功能记录、电路映射和行为分析。在第一个目标中， 我们将测试消融通常支持浦肯野细胞去抑制的MLI-到-MLI连接是否会影响 攀爬纤维的能力，以唤起全面的钙信号，以响应运动错误，以及是否损失 MLI-MLI回路功能影响小脑依赖性运动学习。在第二个目标中，我们将建立一个 MLI分类，并使用它来调查以前未知的MLI亚型。我们还将使用函数 记录，以测试是否有证据表明MLI网络内的偏见连接，支持 浦肯野细胞去抑制的专用电路。在第三个目标中，我们将使用解剖追踪来确定 MLI连接体。通过这种方式，我们将确定是否存在独立驱动MLI的结构基础 亚型通过其传入输入和其传出输出的细胞类型选择性。完成这些 目标将导致对分子层的组织逻辑的前所未有的理解。在 特别是，我们希望揭示分子层内的电路如何控制攀爬纤维的诱导， 中介学习这些知识不仅有助于发展小脑功能的理论/模型， 也提供了深入了解的过程中学习的一般。