NEURAL CONTROL OF GOAL DIRECTED HEAD MOVEMENT

大脑机制程序头部运动将在谷仓研究 猫头鹰作为理解运动系统原理的模型系统 组织和感觉运动整合。 猫头鹰的视神经顶盖 （上级丘）发出指令，将头部重新定向到刺激 在tectum的网站活动代表的方向， 所需运动的大小。 运动代码是“高阶”的， 它规定了方向的变化，但不是必须改变的力。 在特定的肌肉中产生以完成运动。 这个地方 用于移动的代码随后通过以下步骤被转换成中间代码： 4个独立的扫视发生器表示正交（上，下， 左和右）矢量分量。 这 将使用以下方法研究电机命令信号的变换 微刺激、神经生理学、解剖学和行为学 技术;谷仓猫头鹰被选中是因为它们非常准确， 快速的头部运动。 具体地说，我们将确定哪些原子核在 脑干负责将位置码转换为向量 成分代码，以及生理和解剖机制， 转换完成。 此外，我们还将解决 基本问题是如何通过校准电机命令信号， 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 这是一个复杂的多关节系统中运动控制的基础。 在 此外，这些研究将告诉我们大脑是如何代表 所需的运动，如何以及运动的组成部分是在 并行，以及信息如何从一种代码转换为另一种代码， 从一个参照系到另一个参照系。 关于大脑如何编程的知识 和执行动作将是重要的发展， 假肢学、机器人学和计算理论， 以及对大脑功能原理的理解 这些信息将 也为准确解释临床体征提供了基础 涉及头部运动控制（例如痉挛性斜颈， 核上性麻痹等），用于诊断中枢运动障碍 起源，并设计最佳的治疗和纠正程序， 某些运动功能障碍

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.