NEURAL CONTROL OF HEAD MOVEMENT

我们的长期目标是定义神经机制 感官输入到适当的马达输出。在这里，我们建议采用 通过定义前庭脊髓和网状脊髓的作用来实现这一目标 前庭结肠反射和头部神经元(VSNs、RSNs) 定向。在警觉和去大脑动物身上的平行实验将 探索作为动力学和运动学基础的神经机制 由录像机产生的头部运动的组织或通过刺激 上丘。我们的具体目标是： 1.定义VSN和RSNs响应的空间和动态特性 前庭刺激。这些属性是：a)方向 在三维空间中最大限度地刺激神经元的旋转，b)其 频率响应和c)其对阶跃变化的响应的潜伏期 角速度。这3个属性共同定义了 前庭信号在迷路和迷路之间的转换 并提示哪些途径可能参与了这些 变形。 2.刺激上丘诱发的RSNs相关反应 由相同的刺激产生颈部运动激活。这种关系 将指示所携带的头部定向信号的空间属性 就在那个RSN旁边。反应的时间将提示参与的途径 正在生成它。 3.确定VSN、RSN与颈部运动池的连接。四 将使用各种方法来衡量这些联系：形态 VSNs和RSNs的终端茎的检查，尖峰触发的平均 在VSN或RSN放电后颈部肌电活动的变化， 记录肌肉对VS或RS轴突微刺激的反应，以及 神经关联性的相关性计算及其他度量 和运动神经元放电。 来自所有三个AIMS的组合数据将通过以下方式完全描述每个神经元 确定它如何收集源自特定的输入信号 迷路感受器或输出神经元在明确的上 丘脑运动图及其如何将这些信号分配到特定的颈部 汽车共用车。这些信息将使我们能够分析每个人的角色 前庭脊髓和网状脊髓神经元群在产生整体 在VCR或TECO-COLLIC系统中发生的感应电机变换。 我们希望，我们在这一努力中取得的成功将为 对其他人体运动系统进行类似的综合分析 必须进行类似的输入/输出转换。

Our long term goal is to define the neural mechanisms that transform sensory inputs into appropriate motor outputs. Here we propose to approach this goal by defining the roles of vestibulospinal and reticulospinal neurons (VSNs, RSNs) in the vestibulocolic reflex (VCR) and in head orienting. Parallel experiments in alert and decerebrate animals will explore the neural mechanisms that underlie the dynamic and kinematic organization of head movements produced by the VCR or by stimulation of the superior colliculus. Our specific aims are: 1. Define spatial and dynamic properties of response of VSNs and RSNs to vestibular stimulation. These properties are: a) the direction of rotation in 3-dimensional space that maximally excites the neuron, b) its frequency response and c) the latency of its response to a step change of angular velocity. Collectively these 3 properties define the transformation of vestibular signals that occurs between labyrinth and neuron and suggest which pathways may be involved in generating those transformations. 2. Relate response of RSNs elicited by stimulation of superior colliculus with neck motor activation produced by the same stimulus. This relation will indicate the spatial properties of the head orienting signal carried by that RSN. Timing of the response will suggest the pathways involved in generating it. 3. Determine connections of VSNs, RSNs with neck motor pools. Four approaches will be used to measure these connections: morphological examination of terminal arbors of VSNs and RSNs, spike-triggered averaging of changes in neck EMG activity following discharge of a VSN or RSN, recording muscle responses to microstimulation of VS or RS axons, and computation of correlation and other measures of the relatedness of neural and motoneuron discharge. Combined data from all 3 aims will completely characterize each neuron by determining how it collects input signals that originated in specific labyrinthine receptor or output of neurons in the well-defined superior colliculus motor map and how it distributes these signals to specific neck motor pools. This information will allow us to analyze the role of each vestibulospinal and reticulospinal neuron group in producing the overall sensorimotor transformation that occurs in the VCR or tecto-collic systems. We hope that our successes in this endeavor will establish a trend for performing similar comprehensive analyses of other somatomotor systems where analogous input/output transformations must occur.