Cellular and neuronal circuit mechanisms involved in locomotor activity

参与运动活动的细胞和神经元回路机制

• 批准号: 10587675
• 负责人: George Z Mentis
• 金额: $ 64.33万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-12-01 至 2027-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10587675
• 关键词: Adult; Anatomy; Animal Behavior; Animal Model; Animals; Automobile Driving; Axon; Behavior; Behavioral Assay; Biological Assay; CAV2 gene; Cells; Cerebellum; Characteristics; Confocal Microscopy; Connexins; Coupled; Coupling; Critical Thinking; Data; Dependence; Development; Exhibits; Extensor; Flexor; Foundations; Generations; Genetic; Genetic Transcription; Goals; HCN1 gene; HCN4 gene; Image; Immunohistochemistry; Individual; Interneurons; Knockout Mice; Label; Lasers; Left; Limb structure; Locomotion; Maintenance; Maps; Mediating; Molecular; Morphology; Motor; Motor Activity; Motor Neurons; Movement; Mus; Muscle; Neonatal; Neurons; Nodal; Pattern; Periodicity; Peripheral; Pharmacology Study; Physiological; Population; Property; Protocols documentation; Publishing; RNA Interference; Reporting; Role; Sensory; Solid; Speed; Spinal; Spinal Cord; Spinocerebellar Tracts; Synapses; Techniques; Testing; Vertebral column; Viral; Virus; Work; ZFHX3 gene; central pattern generator; conditional knockout; experimental study; genetic approach; in vivo; knock-down; limb movement; locomotor control; mouse genetics; mouse model; neonatal mice; neuronal circuitry; neuroregulation; novel; optogenetics; patch clamp; postnatal; postnatal development; sensory feedback; transcription factor; two-photon

Project Summary Mammalian locomotion is an essential behavior for mobility and survival. Locomotion involves coordinated and alternating rhythmic activity between opposing limbs, as well as between antagonistic muscles of the same limb. The locomotor central pattern generator (CPG), a network of spinal interneurons, is thought to produce the locomotor pattern and rhythm and directly activate motor neurons, which in turn activate peripheral muscles resulting in movement. We have recently reported that a set of spinal interneurons, known as ventral spinocerebellar tract (VSCT) neurons, are both necessary and sufficient for locomotor behavior in neonatal and adult mice. VSCT neurons possess two rhythmogenic properties, namely the exhibit an Ih current and they are electrically coupled. Additionally, they possess spinal axon collaterals within the same spinal segment as well as extra-segmentally. VSCTs are also contacted by motor neuron axon collaterals and they are electrically coupled to them, at least during early postnatal development. VSCTs in turn, connect with other spinal interneurons involved in the locomotor central pattern generator, via their axon collaterals. Our published observations provide a strong foundation to dissect further their cellular characteristics and their neuronal circuits that they form with other spinal neurons, including motor neurons. We hypothesize that both cellular characteristics in VSCTs and the spinal neuronal targets contacted by VSCTs’ axon collaterals will be key determinants for locomotor behavior in mice. In Aim 1, we will study the contribution of the HCN channels responsible for the Ih current in VSCTs and determine the role of several connexins that we have identified through our preliminary results in their role as key neurons in locomotor rhythmogenesis. To do so, we will utilize conditional knock out mice, whole-cell patch clamp protocols along with pharmacological studies, immunohistochemistry, and virally-mediated channel knockdown. In Aim 2, we will study the neuronal connectivity of VSCTs with Chx10+, Sim1+ and motor neurons. We will investigate their functional role in these connections utilizing mouse genetics, behavioral assays, physiological approaches and viral-mediated approaches to map out some of the key neuronal circuits involved in locomotor behavior. Furthermore, we will employ a novel “clearing” technique together with 2-photon laser confocal microscopy to image the entire spinal cord of neonatal and adult mice to uncover the relationship between VSCTs and their potential neuronal targets within the spinal cord and across many different spinal segments. In Aim 3, we will establish whether a novel set of transcription factors marking this class of spinal interneurons can be manipulated by chemogenetic and optogenetic approaches and determine their involvement in locomotor-like behavior. In summary, this comprehensive set of experiments will provide a solid foundation to further our understanding of spinal locomotor networks.

项目概要 哺乳动物的运动是移动和生存的基本行为。运动涉及 对立肢体之间以及对抗肌肉之间协调和交替的有节奏的活动 属于同一个肢体。运动中枢模式发生器（CPG）是一个脊髓中间神经元网络，被认为 产生运动模式和节律并直接激活运动神经元，进而激活外周神经元 肌肉导致运动。我们最近报道了一组脊髓中间神经元，称为腹侧神经元 脊髓小脑束 (VSCT) 神经元对于新生儿和新生儿的运动行为来说既是必要的也是充分的 成年小鼠。 VSCT 神经元具有两种节律特性，即表现出 Ih 电流，并且它们是 电耦合。此外，它们在同一脊柱节段内拥有脊髓轴突侧支以及 额外的段。 VSCT 也与运动神经元轴突侧支相连，并且它们是电耦合的 对他们来说，至少在产后早期发育期间。 VSCT 反过来与其他脊髓中间神经元连接 通过轴突侧支参与运动中枢模式发生器。我们发表的观察结果提供了 为进一步剖析它们的细胞特征及其形成的神经元回路奠定了坚实的基础 其他脊髓神经元，包括运动神经元。我们假设 VSCT 中的细胞特征和 VSCT 轴突侧支所接触的脊髓神经元目标将是运动行为的关键决定因素 在小鼠中。在目标 1 中，我们将研究负责 VSCT 中 Ih 电流的 HCN 通道的贡献，以及 确定我们通过初步结果确定的几种连接蛋白的作用： 运动节律发生的关键神经元。为此，我们将利用条件敲除小鼠、全细胞补丁 钳协议以及药理学研究、免疫组织化学和病毒介导的通道 击倒。在目标 2 中，我们将研究 VSCT 与 Chx10+、Sim1+ 和运动神经元的神经元连接。 我们将利用小鼠遗传学、行为分析、 生理学方法和病毒介导的方法来绘制一些涉及的关键神经元回路 在运动行为中。此外，我们将采用一种新颖的“清除”技术和 2 光子激光 共聚焦显微镜对新生和成年小鼠的整个脊髓进行成像以揭示其中的关系 VSCT 及其在脊髓内以及许多不同脊髓内的潜在神经元目标之间的关系 段。在目标 3 中，我们将确定是否有一组新的转录因子标记此类脊髓 中间神经元可以通过化学遗传学和光遗传学方法进行操纵并确定它们的参与 类似运动的行为。总之，这套综合实验将为 进一步加深我们对脊髓运动网络的理解。