Transmission of Spike Train Codes Across Spinal Synapses

确定信息在脊髓中从一个神经细胞传递到另一个神经细胞的方式，对于了解脊髓如何发挥作用以产生正常的运动行为非常重要。神经元传递的信息是以动作电位的速率和模式编码的，或者说是沿着轴突传递的“棘波”。虽然一个神经元的平均放电速率对它通过称为突触的化学连接联系的其他神经元的放电有明显的影响，但几乎没有实验证据表明，哪些放电模式的细节可能会从一个神经元传递给另一个神经元，特别是对于具有较小个体影响的突触。这一证据将由根据该奖项将完成的研究提供给Timothy Cope博士和Brian Clark博士。这项工作将使用Ia型肌梭感觉神经元的突触连接到脊髓运动神经元上，这是人们熟悉的伸展反射回路的一部分。此外，这项工作将产生重要的新信息，即当多个感觉神经元的放电部分同步时，它们如何相互作用，这种情况似乎是肌肉长度动态变化期间拉伸敏感感觉神经元的典型行动。这项研究的结果将在两个方面具有重要意义：第一，它将揭示感觉神经元尖峰序列的哪些特征对肌肉和运动的控制实际上是重要的；第二，它将详细说明突触连接相对较弱的神经元之间的影响，从而揭示突触之间的信息传输模式。这项基础研究将有助于理解中枢神经控制运动的方式。

Identifying the way in which information is transferred from one nerve cell to another in the spinal cord is important to understanding how the spinal cord functions to produce normal motor behavior. Information conveyed by a neuron is encoded in the rate and pattern of action potentials, or "spikes" transmitted along its axon. While one neuron's average rate of firing has clear effects on the firing of other neurons that it contacts through chemical connections called synapses, there is little experimental evidence as to what details of firing pattern may be transmitted from one neuron to another, especially for synapses that have small individual effects. That evidence will be provided by the research to be done under this award to Drs. Timothy Cope and Brian Clark. The work will use the synapse of type Ia muscle spindle sensory neurons onto spinal motoneurons, which is part of the familiar stretch reflex circuitry. In addition, this work will yield important new information on how multiple sensory neurons interact when their firing becomes partially synchronized, a situation that appears to typify the action of stretch-sensitive sensory neurons during dynamic changes of muscular length. The results of this research will be significant in two ways: first, it will reveal what features of the spike trains of sensory neurons are actually important for the control of muscles and movements; and second, it will detail the influence between neurons that have a relatively weak synaptic connection, thus shedding light on the mode of information transfer across synapses. This basic research will contribute to understanding the way in which the central nervous controls movement.