MOTOR LEARNING IN SMOOTH PURSUIT EYE MOVEMENTS

流畅的追逐眼球运动响应移动的对象，试图产生流畅的眼球运动，使眼睛保持指向移动的对象。追逐的神经基础是众所周知的。视觉输入产生于视网膜，通过外侧膝状核到达大脑皮层。它们被传输到处理运动图像的纹外视觉区域，并通过脑桥和小脑到达眼球运动系统的最终脑干运动路径。这项建议试图理解学习是如何在追逐系统中发生的。如果一只猴子跟踪一个以初始速度移动的目标100毫秒，然后步入一个更高或更低的速度，那么学习就发生在追逐的开始。学习是在反应的最早部分表现出来的，远远早于关于目标速度变化的第一次视觉反馈。这意味着学习发生在将视觉输入转化为运动指令的前馈通路中。本申请有4个具体目的，将阐明追寻学习的神经基础。1)在学习习得过程中，通过跟踪神经元的反应来确定追求学习的表征。本实验将在记录小脑的弓形额叶追踪区(FPA)、颞中视区(MT)和动眼蠕虫时进行。2)通过记录学习对刺激FPA引起的顺畅眼球运动的影响，研究学习是否发生在FPA下游。3)通过询问学习是否是在将目标运动与刺激FPA相匹配的人工条件下诱导出来的，来寻找导致学习的途径。如果刺激诱导的追逐启动增强进入学习现场(S)，则该实验可能导致眼球加速的持续性增加。4)开发一种方法，允许在注视过程中通过刺激MT来诱发眼动，并确定学习如何改变这些眼动。这四个目标将揭示学习是发生在感觉区域还是运动区域，以及学习相对于追求的感觉-运动加工而言是局部性的。它还将询问学习是通过改变视觉-运动传递的增益来实现的，还是通过改变视觉-运动传递的在线增益来实现的，或者通过改变该过程的调制来实现的，如通过在线增益控制来探测的。这些实验将提供有关皮质-桥脑-小脑回路的基本知识，这些回路通常涉及神经疾病。

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.