NEURAL CONTROL OF HEAD MOVEMENT

我们的长期目标是确定神经机制， 将感官输入转化为适当的运动输出。 在这里，我们建议接近 通过定义前庭脊髓和网状脊髓的作用， 前庭反射（VCR）和头神经元（VSNs，RSNs 定向 在警觉和去大脑动物中进行的平行实验将 探索动力学和运动学的神经机制 组织由VCR或刺激产生的头部运动， 上级丘。 我们的具体目标是： 1. 定义VSN和RSN响应的空间和动态特性， 前庭刺激 这些属性是：a）方向 最大程度地激发神经元的三维空间中的旋转，B）其 频率响应和c）其响应于阶跃变化的潜伏期， 角速度 这三个属性共同定义了 前庭信号的转换发生在迷路和 神经元，并提出哪些途径可能参与产生这些 转变 2. 刺激上级丘引起的RSN相关反应 颈部的运动也是由同样的刺激产生的。 这种关系 将指示所携带的头部定向信号的空间特性 这个RSN。 反应的时间将表明参与的途径 生成它。 3. 确定VSN、RSN与颈部运动池的连接。 四 方法将被用来衡量这些连接：形态 VSN和RSN终端心轴的检查，尖峰触发平均 VSN或RSN放电后颈部EMG活动的变化， 记录对VS或RS轴突的微刺激的肌肉反应，以及 相关性的计算和神经网络相关性的其他度量 和运动神经元放电 来自所有3个目标的组合数据将完全表征每个神经元， 确定它如何收集源自特定 明确的上上级神经元的多巴胺受体或输出 丘运动地图以及它如何将这些信号分配到特定的颈部 车辆调配场 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组在产生整体 发生在VCR或tecto-collic系统中的感觉运动转换。 我们希望，我们在这奋进的努力将建立一种趋势， 对其他躯体运动系统进行类似的综合分析 其中必须发生类似的输入/输出变换。

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.