DISCHARGE PATTERNS OF MOTONEURONS

运动神经元的放电模式

• 批准号: 3393924
• 负责人: PEDRO N RUDOMIN
• 金额: $ 5.56万
• 依托单位: NATIONAL POLYTECHNIC INSTITUTE
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-12-01 至 1994-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3393924
• 关键词: action potentials; afferent nerve; cats; cold temperature; cutaneous sensory nerve; dorsal column; dorsal root; electrophysiology; electrostimulus; gamma aminobutyrate; interneurons; locus coeruleus; membrane potentials; microelectrodes; motor cortex; motor neurons; nerve threshold; neural inhibition; neural transmission; neuroanatomy; neuromuscular system; neuropharmacology; red nucleus; reticular formation; spinal nerves; stereotaxic techniques; stimulus /response; synapses; vestibular nuclei

The long term goal of this research is to functionally characterize the neuronal circuitry involved in the presynaptic control of the synaptic effectiveness of primary afferent fibers in the mammalian spinal cord, as well as the role played by presynaptic inhibition in sensory motor integration. To this end we will pursue the following specific aims: Specific Aim 1: In anesthetized or decerebrated cats we will study the possible specificity of the control exerted by cortico-spinal, reticulo-spinal and coeruleo-spinal fibers on the segmental pathways mediating the primary afferent depolarization (PAD) of single group Ia and Ib afferents according to the muscle of origin of the afferent fibers. The action of cortico-spinal inputs will be examined more extensively by studying the effects produced by microstimulation of the motor cortex on the intraspinal threshold of pairs of single Ia and/or lb fibers belonging to the same or to different muscles (flexors and extensors). In addition, studies will be made in decerebrate cats of changes in the PAD patterns of single Ia and Ib fibers before and after blocking impulse conduction in descending pathways by reversible cooling of the thoracic spinal cord. Specific Aim 2: In anesthetized cats, studies will be made on the PAD patterns of functionally identified muscle afferents before and after nerve section and regeneration. The hypothesis to be tested is that the PAD patterns observed in normal Ia and Ib fibers are reestablished after nerve lesions following appropiate reconnection of regenerated afferent fibers with peripheral receptors. Specific Aim 3: Pharmacological and electrophysiological studies of the synaptic actions exerted by last-order intermediate nucleus interneurons on group I afferent fibers and motoneurons will be made in anesthetized cats. Particular attention will be given to test the proposal that the inhibition of motoneurons produced by these interneurons is GABAergic. Studies will be made on the intraspinal distribution and functional characteristics of networks of dorsal horn neurons driving several classes of intermediate nucleus interneurons. Specific Aim 4: Studies will continued in anesthetized cats to further document the observation that during presynaptic inhibition of Ia monosynaptic EPSPs there is no effect on monosynaptic EPSPs produced by stimulation of descending fibers. By means of deconvolution techniques we will examine the effects of stretching synergistic and antagonistic muscles as well as of electrical stimulation of group I fibers on the amplitude and probability distribution of the discrete components of monosynaptic EPSPs produced in the same motoneuron by single Ia fibers and by a small number of descending fibers.

这项研究的长期目标是在功能上表征 突触的突触前控制涉及突触的神经元电路 哺乳动物脊髓中初级传入纤维的有效性，如 以及突触前抑制在感觉运动中的作用 一体化。为此，我们将追求以下具体目标： 特定目的1：在麻醉或脱水的猫中，我们将研究 Cortico-Spinal施加的控制的可能特异性， 节段途径上的网状脊柱和凝血纤维纤维 介导单组IA和 IB传入根据传入纤维的起源肌肉。这 皮质脊柱输入的作用将通过 研究通过微刺激运动皮层对产生的影响 属于单个IA和/或LB纤维对的术中阈值 到相同或不同的肌肉（屈肌和伸肌）。此外， 研究将在pAD模式变化的杂交猫中进行 在阻塞冲动传导之前和之后的单个IA和IB纤维 通过可逆冷却胸脊髓来降低途径。 特定目标2：在麻醉猫中，将在垫子上进行研究 神经前后功能识别的肌肉传入的模式 部分和再生。要测试的假设是 神经后在正常IA和IB纤维中观察到的模式。 适当重新连接再生传入纤维后的病变 带有外围受体。 特定目的3：药理和电生理研究 最后一个中间核中间神经元发挥的突触作用 在第一组上，将在麻醉中进行传入的纤维和运动神经元 猫。将特别注意测试以下提议 这些中间神经元产生的运动神经元的抑制是GABA能。 将进行有关主要分布和功能的研究 驾驶多个课程的背角神经元网络的特征 中间核中间神经元。 特定目的4：研究将继续进行麻醉猫以进一步 记录在突触前抑制IA期间的观察 单突触EPSP对由单突触的EPSP没有影响 刺激下降纤维。通过反卷积技术我们 将检查拉伸协同和拮抗肌肉的影响 以及振幅上I组纤维的电刺激和 单突触EPSP的离散成分的概率分布 由单个IA纤维在同一运动神经元中产生 下降纤维。