NEURAL CONTROL OF GOAL DIRECTED HEAD MOVEMENT

编程头部运动的大脑机制将在谷仓中进行研究 OWL作为理解电机系统原理的模型系统 组织和传感器电机集成。猫头鹰视神经顶盖 (上丘)发出命令，将头部重定向到刺激 来源；顶盖内的场地活动代表了方向和 所需移动的大小。马达代码是“高阶”的 它指定了方向的变化，但不是必须的力 产生特定的肌肉来完成运动。这个地方 用于运动的代码随后通过以下方式转换为中间代码 4个独立的扫视生成器，表示正交性(向上，向下， 左和右)向量分量，如果需要的移动。这 马达指令信号的转换将使用 微刺激、神经生理学、解剖学和行为学 技巧；之所以选择谷仓猫头鹰，是因为它们制造的非常准确， 头部快速移动。具体地说，我们将确定 脑干负责将地点代码转换为矢量 组件编码，以及其生理和解剖学机制 转换完成了。此外，我们还将解决这些问题 基本问题，如如何校准电机指令信号 视觉体验以及头部移动的命令是否在 以头部为中心或以身体为中心的参照系。 这些研究的结果将阐明计算策略 在一个复杂的多关节系统中，这是电机控制的基础。在……里面 此外，这些研究将教会我们大脑是如何代表 所需的运动、运动的处理方式以及运动的哪些组成部分 并行，以及信息如何从一种代码转换到另一种代码，以及 从一个参考系到另一个参考系。了解大脑程序是如何 和执行动作将是重要的发展 修复学、机器人学和计算理论，以及我们的理解 以及对大脑功能原理的欣赏。这样的信息将 也为临床体征的准确解释提供了基础 涉及头部运动控制(例如痉挛性斜颈， 核上性瘫痪等)，用于诊断中枢运动障碍 起源，并用于设计最佳治疗方法和矫正程序 某些类别的运动功能障碍。

Brain mechanisms that program head movements will be studied in the barn owl as a model system for understanding principles of motor system organization and sensorimotor integration. The owl's optic nerve tectum (superior colliculus) issues commands that redirect the head to stimulus sources; the site activity in the tectum represents the direction and magnitude of the desired movement. The motor code is "high-order" in that it specifies a change in orientation, but not the forces that must be generated in particular muscles to accomplish the movement. This place code for movement is subsequently transformed into an intermediate code by 4 independent saccade generators which represent orthoganal (up, down, left and right) vector components if the desired movement. This transformation of motor command signals will be studied using microstimulation, neurophysiological, anatomical, and behavioral techniques; barn owls are chosen because they make extremely accurate, rapid head movements. Specifically, we will determine which nuclei in the brainstem are responsible for transforming the place code into vector component code, and the physiological and anatomical mechanisms by which the transformation is accomplished. In addition, we will address such fundamental issues as how the motor command signals are calibrated by visual experience and whether the commands for head movement are issued in a head-centered or a body-centered frame of reference. The results of these studies will elucidate the computational strategies that underlie motor control in a complex, multi-articulated system. In addition, these studies will teach us about how the brain represents desired movements, how and what components of movement are processed in parallel, and how information is translated from one code to another and from one reference system to another. Knowledge of how the brain programs and executes movements will be important to the development of prosthetics, robotics and computational theory, and to our understanding and appreciation of principles of brain function. Such information will also provide a foundation for accurate interpretation of clinical signs relating to head movement control (such as spasmodic torticollis, supranuclear palsy, etc.), for diagnosis of movement disorders of central origin, and for designing optimal therapies and corrective procedures for certain classes of motor dysfunction.