Vestibular and Visual Control of Eye Movement

描述(申请人提供)：动作学习是通过练习使动作变得流畅和准确的过程。运动学习依赖于被称为小脑的大脑区域，而小脑功能障碍的患者会出现笨拙、不协调的运动。这个项目研究了引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，并确定控制该运动的运动程序何时需要更新？几十年来，人们一直认为，从下橄榄到小脑的“攀登纤维”输入是指导运动学习的唯一指导信号。然而，我们最近发现，在攀爬纤维没有反应的训练条件下，可以诱导运动学习。拟议的实验分析了运动学习中这种攀爬纤维无关的成分。特别是，我们将研究控制学习这一组成部分的指导性信号的来源，并确定它可以和不能调节运动的哪些方面。这个项目利用眼球运动的实验可控性，特别是前庭-眼睛反射(VOR)，来分析运动学习的神经机制。VOR是一种反射性眼球运动，通过唤起与头部运动相反的眼球运动来减少视觉图像在视网膜上的运动。运动学习的一种形式，称为VOR适应，当图像运动与头部旋转持续联系在一起时，通过逐渐纠正反射来校准VOR。VOR适应对于确保在转头时有足够的视觉敏锐度以及恢复空间中正确的运动和感知方向至关重要，以应对生物体或其环境的变化，例如随着生长发育、衰老、外周或中枢神经系统的损伤或戴上新眼镜而发生的变化。 与公共健康相关：这个项目将提高我们对控制学习诱导的神经机制的理解。这一认识的提高应该有助于设计有效的学习和记忆障碍的补救策略以及中枢神经系统或外周损伤的康复策略。

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.