Circuit Specializations of Cerebellar Molecular Layer Interneurons

小脑分子层中间神经元的电路特化

• 批准号: 10722374
• 负责人: Elizabeth Lackey
• 金额: $ 6.87万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10722374
• 关键词: Affective; Anatomy; Ataxia; Attention deficit hyperactivity disorder; Axon; Behavior; Behavior Control; Biological Models; Brain; Brain Diseases; Cells; Cerebellar Cortex; Cerebellar Diseases; Cerebellum; Cognitive; Coupled; Coupling; Data; Disease; Disinhibition; Dystonia; Electron Microscopy; Electrophysiology (science); Elements; Equilibrium; Eye Movements; Foundations; Future; Gap Junctions; Image; Inhibitory Synapse; Injury; Interneurons; Learning; Link; Lobule; Maps; Modeling; Molecular; Morphology; Mus; Myoepithelial cell; Neurologic; Outcome; Output; Population; Presynaptic Terminals; Property; Purkinje Cells; Role; Schizophrenia; Signal Transduction; Slice; Structure; Synapses; Target Populations; Thick; Tremor; Whole-Cell Recordings; Work; autism spectrum disorder; connexin 36; experimental study; extracellular; granule cell; improved; in vivo; insight; mossy fiber; motor learning; mouse genetics; nervous system disorder; neural; neuropsychiatric disorder; neuropsychiatry; postsynaptic; reconstruction; single nucleus RNA-sequencing; stellate cell; therapeutic target

Project Summary The cerebellum controls behaviors that depend on prediction, including motor learning, eye movements, balance, and cognitive-affective functions. The cerebellar cortex transforms mossy fiber (MF) inputs into Purkinje cell (PC) outputs. It is vital to delineate the elements of this circuit and their connectivity to relate circuit properties to function and disease. To improve our understanding of transformations in the cerebellar cortex, this proposal seeks to delineate the circuit properties of the most abundant type of interneuron in the cerebellum, the molecular layer interneuron (MLI). MLIs inhibit PCs and other MLIs to control the output of the cerebellar cortex. However, single nucleus RNA sequencing recently identified two molecularly distinct types of MLIs, MLI type 1 (MLI1) and MLI type 2 (MLI2). Intriguingly, MLI1s express connexin 36, whereas MLI2s do not. This suggests that MLI1s might be gap junction coupled with each other, which could promote synchronous firing and make MLI1s well-suited to controlling the timing of PC outputs. The circuit properties of MLI1 and MLI2 are not known. Here I will clarify MLI1 and MLI2 connectivity using slice electrophysiology and serial electron microscopy (EM) reconstructions in mice. The first aim of this proposal is to determine the outputs of MLI1 and MLI2 using paired whole-cell recordings in brain slice. First, I will characterize MLI1 and MLI2 synaptic connections onto PCs. I will also characterize the contributions of MLI1 and MLI2 to ephaptic inhibition, which arises from large extracellular signals near MLI specializations known as pinceaux that surround PC axon initial segments. Lastly, I will characterize synaptic connections and electrical coupling between MLI1 and MLI2. The second aim of this proposal is to characterize the ultrastructural circuit specializations of MLI1 and MLI2 and generate a comprehensive map of MLI1 and MLI2 synaptic and ephaptic connectivity using large-scale EM reconstructions. The complementary approaches of electrophysiological characterization and EM reconstructions will provide a complete picture of the functional properties and the anatomical connectivity. Preliminary findings suggest that MLI1 and MLI2 target different cells, with MLI1s mainly inhibiting PCs, whereas MLI2s primarily inhibit other MLIs. Based on these preliminary studies, my working model is that MLI1s are well suited to controlling the timing of PC outputs, whereas MLI2s promote PC excitability by disinhibiting PCs. Completion of the proposed work will define the properties of these circuit elements, and if preliminary results are confirmed, it will be necessary to revise the circuit diagram of the cerebellar cortex. These experiments will also lead to future studies that will determine the in vivo firing properties of MLI1 and MLI2 and determine how MLI1 and MLI2 contribute to processing, learning and behavior. These studies promise to shed light on mechanisms of cerebellar computations that are relevant to neurological disorders and neuropsychiatric diseases.

项目概要 小脑控制依赖于预测的行为，包括运动学习、眼球运动、 平衡和认知情感功能。小脑皮层将苔藓纤维 (MF) 输入转化为 浦肯野细胞 (PC) 输出。描述该电路的元件及其连接性至关重要 电路特性对功能和疾病的影响。提高我们对小脑转变的理解 皮层，该提案旨在描绘大脑皮层中最丰富的中间神经元类型的电路特性 小脑，分子层中间神经元（MLI）。 MLI 禁止 PC 和其他 MLI 来控制输出 小脑皮质。然而，单核 RNA 测序最近发现了两种分子上不同的类型 MLI、MLI 类型 1 (MLI1) 和 MLI 类型 2 (MLI2)。有趣的是，MLI1 表达连接蛋白 36，而 MLI2 则表达连接蛋白 36。 不是。这表明 MLI1 可能通过间隙连接相互耦合，从而促进 同步触发并使 MLI1 非常适合控制 PC 输出的时序。电路特性 MLI1 和 MLI2 未知。在这里，我将使用切片电生理学来阐明 MLI1 和 MLI2 连接性 小鼠的连续电子显微镜（EM）重建。该提案的首要目标是确定 使用脑切片中配对的全细胞记录来输出 MLI1 和 MLI2。首先，我将描述 MLI1 和 MLI2 突触连接到 PC。我还将描述 MLI1 和 MLI2 对 ehaptic 的贡献 抑制，由 MLI 特化附近的大细胞外信号（称为 pinceaux）产生， 围绕 PC 轴突初始段。最后，我将描述突触连接和电耦合的特征 MLI1 和 MLI2 之间。该提案的第二个目标是表征超微结构电路 MLI1 和 MLI2 的专业化，并生成 MLI1 和 MLI2 突触和突触的综合图 使用大规模电磁重建的连接性。电生理学的补充方法 表征和电磁重建将提供功能特性和 解剖连接性。初步研究结果表明，MLI1 和 MLI2 靶向不同的细胞，其中 MLI1 主要抑制 PC，而 MLI2 主要抑制其他 MLI。基于这些初步研究，我的 工作模型是 MLI1 非常适合控制 PC 输出的时序，而 MLI2 则促进 PC 通过去抑制 PC 来提高兴奋性。完成建议的工作将定义这些电路的特性 元件，如果初步结果得到确认，则有必要修改电路图 小脑皮质。这些实验还将导致未来的研究确定体内放电 MLI1 和 MLI2 的属性，并确定 MLI1 和 MLI2 如何有助于处理、学习和 行为。这些研究有望揭示与以下相关的小脑计算机制 神经系统疾病和神经精神疾病。

项目成果

Specialized connectivity of molecular layer interneuron subtypes leads to disinhibition and synchronous inhibition of cerebellar Purkinje cells.

分子层中间神经元亚型的特殊连接导致小脑浦肯野细胞的去抑制和同步抑制。

• 发表时间: 2024-04-26
• 影响因子: 16.2
• 作者: Lackey, Elizabeth P;Moreira, Luis;Norton, Aliya;Hemelt, Marie E;Osorno, Tomas;Nguyen, Tri M;Macosko, Evan Z;Lee, Wei;Hull, Court A;Regehr, Wade G
• 通讯作者: Regehr, Wade G