INPUT-OUTPUT BEHAVIOR OF REAL AND MODEL MOTONEURONS

真实运动神经元和模型运动神经元的输入输出行为

• 批准号: 2269884
• 负责人: RANDALL K POWERS
• 金额: $ 11.75万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-01 至 1998-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2269884
• 关键词: action potentials; cats; computational neuroscience; electrophysiology; hypoglossal nerve; membrane potentials; motor neurons; nerve threshold; neural transmission; spinal cord; synapses

DESCRIPTION: (Taken from applicant's abstract) The integrative function of the nervous system is predicated on the input-output properties of its individual neural elements. Although there are a number of empirical and analytical models of neuronal input-output behavior, none of them has general predictive value. The goal of the proposed research is to test and refine a computer model of a neuron that is based on the biophysical properties, is computationally tractable, and that accurately recreates neuronal input-output behavior over a wide range of conditions. The proposed work will primarily involve experimental measurement of the effects of synaptic and injected currents on the repetitive discharge of alpha motoneurons from the intact cat spinal cord in combination with computer simulation of the observed behaviors. The research design is based on the hypothesis that the response of a repetitively discharging neuron to synaptic input is determined by three processes: (1) the delivery of synaptic current to the soma (and the subsequent change in somatic membrane potential); (2) the interspike trajectory of somatic membrane potential; and (3) the interspike trajectory of voltage threshold. Project 1 is designed to examine the capacity of injected current transients to advance or delay spikes in repetitively discharging motoneurons in order to quantify variation in the voltage threshold for spike initiation. In Project 2, the effects of injected current transients on spike discharge will be compared to those of postsynaptic potentials from three identified sets of presynaptic neurons. In Project 3, a novel frequency matching paradigm will be used to compare the responses of real and model motoneurons to slowly-varying injected currents. This approach will be extended in Project 4 to an in vitro preparation of rat hypoglossal motoneurons in which long, stable intracellular recordings and more precise control of the extracellular environment are possible. In Project 5, neuromodulatory effects on neuronal input-output behavior will be studied by comparing motoneuron responses to selected inputs in four distinct preparations: intact barbiturate-anesthetized cats; unanesthetized decerebrate cats; decerebrate cats during stimulation of the mesencephalic locomotor region; and decerebrate-spinal cats with i.v. injection of serotonergic and noradrenergic precursors. The results of these studies will improve our understanding of the mechanisms underlying neuronal input-output behavior, and will also aid the interpretation of both human and chronic animal electrophysiological studies in which synaptic events are inferred from changes in motoneuron discharge.

描述：（取自申请人的摘要）综合功能 神经系统的输入输出属性是 它的个体神经元素。 虽然有很多 神经元输入行为的经验和分析模型，无 它们中有一般的预测价值。 拟议研究的目标 是测试和完善基于神经元的计算机模型 生物物理特性，在计算上是可以处理的，并且 准确地重现在宽范围内的神经元输入行为 条件。 拟议的工作主要涉及实验 测量突触和注入电流对 从完整的猫脊柱中重复排放α运动神经元 与观察到的行为的计算机模拟结合使用。 研究设计基于以下假设 重复地将神经元放电到突触输入由三个确定 过程：（1）突触电流传递到SOMA（以及 随后的体膜电位变化）； （2）串联 体膜电位的轨迹； （3）乘坐式鞋 电压阈值的轨迹。 项目1旨在检查 注射电流瞬变的能力以推进或延迟峰值 重复放出运动神经元，以量化 尖峰启动的电压阈值。 在项目2中，效果 将尖峰放电的注射电流瞬变与 从三个已确定的一组中的突触后潜能 突触前神经元。 在项目3中，一个新颖的频率匹配范例 将用于将真实和模型运动神经元的响应与 缓慢变化的注入电流。 这种方法将扩展 项目4至大鼠降压运动神经元的体外制备 长期稳定的细胞内记录以及对 细胞外环境是可能的。 在项目5中 将研究对神经元输出输出行为的神经调节作用 通过比较运动神经元对四个不同的输入的响应 制剂：完整的巴比妥酸酯麻醉猫；打开措施 脑猫;刺激期间的脑猫 中脑运动区；和静脉内的脊椎动物猫 注射血清素能和去甲肾上腺素能的前体。 结果 这些研究将提高我们对机制的理解 潜在的神经元输出行为，也将有助于 人类和慢性动物电生理学的解释 从运动神经元的变化推断出突触事件的研究 释放。