INPUT-OUTPUT BEHAVIOR OF REAL AND MODEL MOTONEURONS

描述：(摘自申请人的摘要)综合功能 神经系统的输入输出特性是建立在 它的单个神经单元。尽管有一些 神经元输入-输出行为的经验和分析模型，无 其中一些具有普遍的预测价值。拟议研究的目标是 是测试和改进一个神经元的计算机模型 生物物理性质，在计算上是容易处理的，而且 在大范围内准确地重现神经元的输入输出行为 条件的问题。拟议的工作将主要涉及试验性工作。 突触电流和注入电流对脑电活动的影响 猫完整脊髓α运动神经元的重复放电 CORD结合计算机模拟观察到的行为。 这项研究的设计是基于这样的假设： 神经元向突触输入的重复放电由三个因素决定 过程：(1)向胞体传递突触电流(和 体细胞膜电位的随后变化)；(2)穗间波 体细胞膜电位的轨迹；(3)棘波 电压阈值的轨迹。项目1旨在检查 注入电流瞬变提前或延迟尖峰的能力 重复地释放运动神经元，以量化 尖峰触发的电压阈值。在项目2中，影响 尖峰放电时注入电流瞬变的百分比将与 已鉴定的三组突触后电位的比较 突触前神经元。在项目3中，一种新的频率匹配范例 将用于比较真实运动神经元和模型运动神经元对 缓慢变化的注入电流。这一方法将在 项目4大鼠舌下运动神经元的体外制备 哪些长的、稳定的细胞内记录和更精确的控制 胞外环境是可能的。在项目5中， 将研究神经调节对神经元输入输出行为的影响 通过比较四个不同类型的运动神经元对选定输入的反应 制备：完整巴比妥酸盐麻醉的猫；未麻醉的猫 取消猫的大脑；在刺激猫的过程中取消猫的大脑 中脑运动区；去脑脊髓猫静脉注射。 注射5-羟色胺能和去甲肾上腺素能前体。结果是 这些研究将提高我们对这些机制的理解。 潜在的神经元输入输出行为，也将有助于 对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突触事件的研究 出院。

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.