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.

项目摘要 哺乳动物的运动是流动性和生存的基本行为。运动涉及 对方的四肢以及拮抗肌肉之间的协调和替代节奏活动 相同的肢体。运动中心模式发生器（CPG）是脊柱中间神经元网络，被认为是 产生运动模式和节奏，并直接激活运动神经元，进而激活周围 肌肉导致运动。我们最近报告说，一组脊柱中间神经元，称为腹 脊椎小脑道（VSCT）神经元，对于新生儿的运动行为是必要且足够的 成年小鼠。 VSCT神经元具有两种节奏特性，即暴露于IH电流，它们是 电耦合。此外，它们在同一脊柱段以及 外部分段。运动神经元轴突侧支也接触了VSCT，并与电耦合 至少在产后早期发展期间。 VSCTS依次与其他脊柱中间神经元联系 通过其轴突侧支参与运动中心模式发生器。我们发表的观察结果 它们与它们形成的细胞特征和神经元电路的强大基础 其他脊柱神经元，包括运动神经元。我们假设VSCT和 VSCTS的轴突侧支联系的脊柱神经元靶标将是运动行为的关键决定者 在老鼠中。在AIM 1中，我们将研究负责VSCT中IH电流的HCN渠道的贡献 确定我们通过初步结果确定的几种连接蛋白在其作用中确定的作用 运动节律发生中的关键神经元。为此，我们将利用有条件的敲除小鼠，全细胞贴片 夹具方案以及药物研究，免疫组织化学和病毒介导的通道 击倒。在AIM 2中，我们将研究使用CHX10+，SIM1+和运动神经元的VSCT的神经元连通性。 我们将利用小鼠遗传学，行为分析，调查它们在这些连接中的功能作用， 生理方法和病毒介导的方法来绘制一些关键的神经元电路 在运动行为中。此外，我们将采用一种新颖的“清除”技术以及2片激光器 共聚焦显微镜图像新生儿和成年小鼠的整个脊髓成像以发现关系 VSCTS及其在脊髓内的潜在神经元靶标之间以及许多不同的脊柱 细分市场。在AIM 3中，我们将确定是否有一组标记这类脊柱的新型转录因子 中间神经元可以通过化学遗传学和光遗传学方法来操纵，并确定其参与 在类似运动的行为中。总而言之，这套全面的实验将为 进一步，我们对脊柱运动网络的理解。