Visuomotor Adaptation in Human Reaching

描述(申请人提供)：将研究感觉运动适应的机制，重点是在暴露于改变的视觉反馈后，视觉引导的伸展的快速重新校准。这项研究将结合人类心理物理实验和计算模型来详细了解感觉反馈是如何驱动视觉运动地图的重新校准的。一种基于虚拟现实的心理物理设备将被用于在手臂的视觉反馈中引入空间扰动，其方式类似于经典的“棱镜适应”实验。将使用一系列心理物理测量来量化从视觉到运动转变过程中的中间阶段的适应反应，包括眼睛-身体和身体-手臂校准以及习得的矫正反应。本研究将集中于三个具体目标：(1)视觉运动适应的时间动力学研究。将收集运动输出和感觉反馈的逐次试验统计数据，并将用于测试几类计算模型，以确定来自每一次潮汐的感觉反馈如何影响视觉运动图，从而影响下一步运动。(2)REACH适应中的空间概化研究。将确定从到达一个目标位置的反馈对随后到其他目标位置的移动的影响。这些空间概化模式将被用来模拟视觉运动地图的适应自由度，并测试视觉和运动变换序列的合成模型。(3)REACH适应中的“信用分配”问题的研究：鉴于纠错感觉反馈可以在视觉运动通路的多个阶段驱动适应，大脑如何确定哪些适应轨迹应该对给定运动的反馈做出反应？将对感觉反馈的时间、可用的反馈信号以及视觉扰动的程度和形状进行操作，并将测量视觉运动通路上的适应性反应的分布。这些数据将用于对完成信用分配的规则进行建模。这项工作的长期目标是更定量地了解肢体运动中感觉-运动整合，并确定REACH适应的行为和神经基础，作为中枢神经系统感觉-运动可塑性的模型。

DESCRIPTION (provided by applicant): The mechanisms of sensorimotor adaptation will be studied, focusing on the rapid recalibration of visually guided reaching after exposure to altered visual feedback. This research will use a combination of human psychophysical experiments and computational modeling to gain a detailed understanding of how sensory feedback drives recalibration of the visuomotor map. A virtual reality based psychophysical apparatus will be used to introduce spatial perturbations to the visual feedback of the arm in a manner analogous to the classic "prism adaptation" experiments. A range of psychophysical measurements will be used to quantify the adaptive response at intermediate stages along the transformation from vision to movement including eye-body and body-arm calibration as well as a learned corrective response. This research will focus on three specific aims: (1) A study of the temporal dynamics of visuomotor adaptation. The trial-by-trial statistics of both the motor output and the sensory feedback will be collected and will be used to test several classes of computational models for the "learning rules" that specify how sensory feedback from each single tidal effects the visuomotor map and, consequently, the next movement. (2) A study of spatial generalization in reach adaptation. The effect that feedback from reaches to one target location has on subsequent movements to other target locations will be determined. These patterns of spatial generalization will be used to model the adaptive degrees of freedom of the visuomotor map and to test compositional models of the sequence of transformations from vision and movement. (3) A study of the "credit assignment" problem in reach adaptation: given that error corrective sensory feedback can drive adaptation at multiple stages of the visuomotor pathway, how does the brain determine which loci of adaptation should respond to the feedback from a given movement? Manipulations of the timing of the sensory feedback, the feedback signals that are available, and the extent and shape of the visual perturbations will all be performed, and the distribution of adaptive responses across the visuomotor pathway will be measured. These data will be used to model the rules by which credit assignment is accomplished. The long-term goals of this work are to gain a more quantitative understanding of sensorimotor integration in limb movements and to identify the behavioral and neural bases of reach adaptation, as a model for sensorimotor plasticity in the central nervous system.