Vestibular and Visual Control of Eye Movement

描述（由申请人提供）：运动学习是指通过练习使动作变得流畅和准确的过程。运动学习依赖于一个叫做小脑的大脑区域，小脑功能障碍患者的动作笨拙、不协调。这个项目研究指导运动学习的错误信号。小脑或相关神经回路中的哪些神经元监控运动的准确性，并决定何时需要更新控制该运动的运动程序？几十年来，人们一直认为，下橄榄向小脑输入的“攀爬纤维”提供了指导运动学习的唯一指导性信号。然而，我们最近发现运动学习可以在训练条件下被诱导，而不引起攀爬纤维的反应。我们提出的实验分析了运动学习中与攀爬纤维无关的部分。特别是，我们将研究控制这一学习组成部分的指导性信号的起源，并确定它能调节和不能调节运动的哪些方面。本项目利用眼球运动的实验可操控性，特别是前庭眼反射（VOR），来分析运动学习的神经机制。VOR是一种反射性眼球运动，它通过唤起与头部运动相反方向的眼球运动来减少视网膜上视觉图像的运动。运动学习的一种形式，被称为VOR适应，通过逐渐纠正当图像运动与头部转动持续相关时的反射来校准VOR。VOR适应对于确保头部转动时足够的视觉敏锐度，以及在机体或其环境发生变化（如生长发育、衰老、外周或中枢神经系统损伤或戴上一副新眼镜）时，在空间中恢复适当的运动和感知方向至关重要。

DESCRIPTION (provided by applicant): Motor learning is the process by which movements become smooth and accurate through practice. Motor learning depends on a brain region called the cerebellum, and patients with cerebellar dysfunction have clumsy, uncoordinated movements. This project examines the error signals that guide motor learning. Which neurons in the cerebellum or related neural circuitry monitor the accuracy of a movement, and determine when the motor program controlling that movement needs to be updated? For decades it was thought that the "climbing fiber" input to the cerebellum from the inferior olive provided the sole instructive signal guiding motor learning. However, we recently showed that motor learning could be induced under training conditions that elicit no response in the climbing fibers. The proposed experiments analyze this climbing fiber-independent component of motor learning. In particular, we will examine the origin of the instructive signals controlling this component of learning, and we will determine which aspects of movement it can and cannot regulate. This project capitalizes on the experimental tractability of eye movements, in particular the vestibulo-ocular reflex (VOR), to analyze the neural mechanisms of motor learning. The VOR is a reflexive eye movement that reduces motion of visual images on the retina by evoking eye movements in the opposite direction to head movements. A form of motor learning, known as VOR adaptation, calibrates the VOR by gradually correcting the reflex when image motion is persistently associated with head turns. VOR adaptation is essential for ensuring adequate visual acuity during head turns and for restoring proper motor and perceptual orientation in space in response to changes in the organism or its environment, such as occur with growth and development, aging, injury to the peripheral or central nervous system or the donning of a new pair of spectacles. PUBLIC HEALTH RELEVANCE: This project will improve our understanding of the neural mechanisms controlling the induction of learning. This improved understanding should facilitate the design of effective remediation strategies for disorders of learning and memory and rehabilitation strategies for CNS or peripheral injury.