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.

项目摘要 小脑控制取决于预测的行为，包括运动学习，眼动， 平衡和认知影响功能。小脑皮层将苔藓纤维（MF）输入转化为 Purkinje Cell（PC）输出。描述该电路的元素及其连接性至关重要 功能和疾病的电路特性。以提高我们对小脑转变的理解 皮质，该提案旨在描述最丰富类型的中间神经元的电路特性 小脑，分子层中间神经元（MLI）。 MLIS抑制PC和其他MLI来控制该输出 小脑皮质。然而，单核RNA测序最近确定了两种分子不同的类型 MLI，MLI 1型（MLI1）和MLI 2型（MLI2）。有趣的是，MLI1S Express Connexin 36，而MLI2S DO 不是。这表明MLI1可能是间隙连接的，这可能会促进 同步启动并使MLI1非常适合控制PC输出的时间。电路特性 MLI1和MLI2尚不清楚。在这里，我将使用切片电生理学和 小鼠的连续电子显微镜（EM）重建。该提议的第一个目的是确定 MLI1和MLI2的输出，使用脑切片中配对的全细胞记录。首先，我将描述MLI1和 MLI2突触连接到PC。我还将表征MLI1和MLI2对Ephaptic的贡献 抑制作用是由MLI专业附近的大型细胞外信号引起的，称为pinceaux 围绕PC轴突初始段。最后，我将表征突触连接和电气耦合 在MLI1和MLI2之间。该提议的第二个目的是表征超微结构电路 MLI1和MLI2的专业知识，并生成MLI1和MLI2突触的综合图 使用大型EM重建的连接性。电生理学的互补方法 表征和EM重建将提供功能属性的完整图片和 解剖连通性。初步发现表明MLI1和MLI2靶向不同的细胞，MLI1S 主要抑制PC，而MLI2主要抑制其他MLI。基于这些初步研究，我 工作模型是MLI1非常适合控制PC输出的时间，而MLI2S促进PC 通过抑制PC进行兴奋性。提议的工作的完成将定义这些电路的属性 元素，如果确认初步结果，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，以确定体内射击 MLI1和MLI2的属性，并确定MLI1和MLI2如何有助于处理，学习和 行为。这些研究有望阐明与小脑计算的机制 神经系统疾病和神经精神疾病。