MOTOR LEARNING IN SMOOTH PURSUIT EYE MOVEMENTS

平滑的眼球运动对移动的物体做出反应，试图产生平滑的眼球运动，使眼睛始终指向移动的物体。追求的神经基础是众所周知的。视觉输入产生于视网膜，并通过外侧膝状核到达大脑皮层。它们被传送到处理运动图像的外皮层视觉区域，并通过脑桥和小脑到达眼动系统的最终脑干运动通路。这个建议试图理解学习是如何在追求系统中发生的。如果一只猴子跟踪一个以100毫秒的初始速度移动的目标，然后转向更高或更低的速度，那么学习就发生在追求的开始阶段。学习表现在反应的最早部分，远早于关于目标速度变化的第一个视觉反馈。这意味着学习发生在将视觉输入转化为运动命令的前馈通路中。本应用程序有4个具体目的，将阐明追求学习的神经基础。1)通过跟踪神经元在学习习得过程中的反应来确定追求学习的表征。本实验将在小脑弓状额追逐区（FPA）、颞中视觉区（MT）和动眼肌蚓部进行记录。2)通过记录学习对FPA刺激引起的平滑眼动的影响，探讨学习是否发生在FPA下游。3)通过询问学习是否在目标运动与FPA刺激配对的人工条件下诱导，来寻找导致学习的途径。如果刺激引起的追求开始的增强进入了学习的部位，本实验可能会导致眼睛加速的持续增加。4)开发一种方法，允许眼球运动在注视时通过MT刺激引起，并确定学习如何改变这些眼球运动。这四个目标将揭示学习是发生在感觉区域还是运动区域，以及相对于追求的感觉-运动处理，学习是定位在哪里。它还将询问学习是通过改变视觉-运动传输的增益来实现的，还是通过视觉-运动传输的在线增益来实现的，或者通过改变在线增益控制来实现的。这些实验将提供有关皮质-桥-小脑回路的基本知识，这些回路通常与神经系统疾病有关。

Smooth pursuit eye movements respond to moving objects in an attempt to generate smooth eye movements that keep the eyes pointed at the moving object. The neural substrate for pursuit is well known. Visual inputs arise in the retina and pass through the lateral geniculate nucleus to the cerebral cortex. They are transmitted into extrastriate visual areas that process moving images, and through the pons and cerebellum to the final brainstem motor pathways of the eye movement system. This proposal seeks to understand how learning occurs within the pursuit system. If a monkey tracks a target that moves at an initial speed for 100 ms and then steps to a higher or lower speed, then learning occurs in the initiation of pursuit. Learning is expressed in the earliest part of the response, well before the first visual feedback about the change in target velocity. This implies that learning occurs in the feed-forward pathways that transform visual inputs into motor commands. The present application has 4 specific aims that will elucidate the neural basis for pursuit learning. 1) Determine the representation of pursuit learning by following the responses of neurons during the acquisition of learning. This experiment will be done while recording in the arcuate frontal pursuit area (FPA), the middle temporal visual area (MT), and the oculomotor vermis of the cerebellum. 2) Investigate whether learning occurs downstream from the FPA by recording the effect of learning on the smooth eye movements evoked by stimulation of the FPA. 3) Search for pathways that cause learning by asking whether learning is induced under artificial conditions that pair target motion with stimulation of the FPA. This experiment may cause a persistent increase in eye acceleration if the stimulation-induced enhancement of the initiation of pursuit has access to the site(s) of learning. 4) Develop a method that will allow eye movements to be evoked by stimulation of MT during fixation, and determine how learning alters those eye movements. These 4 aims will reveal whether learning occurs in sensory or motor areas, and where learning is localized relative to the sensory-motor processing of pursuit. It will also ask whether learning is implemented by changing the gain of visual-motor transmission, or by alt of that process as probed by on-line gain of visual-motor transmission, or by altering the modulation of that process as probed by on-line gain control. These experiments will provide fundamental knowledge about the cortico-ponte-cerebellar circuits that are commonly involved in neurological disorders.