Planning and Updating in Frontoparietal Networks for Grasping

描述(申请人提供)：在大脑损伤后发生的一些行为后遗症，如中风或创伤，可以用感觉信息和运动指令整合的异常来解释。该项目使用脑成像和非侵入性脑刺激，结合机器人和虚拟环境中抓取运动的新扰动，研究额顶脑区在感觉-运动整合的不同阶段所扮演的角色，并确定为目标定向抓取服务的大脑网络的具体贡献。这个项目的总体目标是使用一个健康的人体损伤模型来对额顶皮质在感觉-运动整合的两个主要阶段中所扮演的角色做出因果推断：在运动规划期间，当目标目标的视觉信息和手的触觉信息被转换为运动命令时，以及在运动更新期间，当估计运动命令的感觉后果时(生成前向模型)。我们利用已经被用来研究REACH系统中的感觉运动整合的涉及目标和手臂运动工厂的扰动(外部空间和内在空间的扰动)的经过时间测试的方法，并将它们应用于研究由一个独特的分离的神经网络控制的抓取电路，该电路被相对较少地研究。这是第一次在人类中进行系统研究，以测试额顶皮质在计划和正向建模抓握手形方面的独特贡献，以及这些过程如何在内在参照系和外在参照系的背景下相互作用。目标1的中心目标是使用功能磁共振成像(FMRI)来识别外部空间和内部空间中运动规划的神经基础，并相应地测试这些区域与经颅磁刺激引起的fMRI神经导航暂时性损害之间的因果关系。目的2通过测试在线GRASH更新中与GRASH相关的额顶区的因果参与，补充了先前的目标。在这里，我们利用对抓握过程中手形和运动目标的新扰动的运动学响应的多变量分析来分离这些区域参与手形正向模型的生成与将感觉信息整合到运动计划中。

DESCRIPTION (provided by applicant): A number of the behavioral sequelae that occur after damage to the brain, such as stroke or traumatic injury, can be explained by abnormalities in the integration of sensory information and motor commands. This project uses brain imaging and non-invasive brain stimulation, combined with novel perturbations of grasping movements with robotics and virtual environments to study the roles played by frontoparietal brain areas in different stages of sensorimotor integration and to identify specific contributions of brain networks subserving goal-directed grasping. The overarching goal of this project is use a healthy-human lesion model to make causal inferences regarding the roles played by frontoparietal cortices in two major stages of sensorimotor integration: during motor planning when visual information of the target goal and haptic information of the hand is transformed into motor commands, and during movement updating when estimates of the sensory consequences of motor commands occur (generation of a forward model). We leverage the time-tested approaches involving perturbations to the target goal and the arm motor plant (perturbations of extrinsic and intrinsic space) that have been used to study sensorimotor integration in the reach system, and apply them to study the grasp circuit, which is controlled by a unique and segregated neural network that is comparatively understudied. This is the first systematic study in humans to test the unique contributions of frontoparietal cortices in planning and forward modeling of hand shape for grasping, and how these processes interact in the context of intrinsic versus extrinsic reference frames. The central goal of Aim 1 is to use functional magnetic resonance imaging (fMRI) to identify the neural bases of motor planning in external vs. internal space and accordingly test the causal involvement of these regions with fMRI-neuronavigated transient lesions elicited with transcranial magnetic stimulation. Aim 2 complements the previous aim by testing the causal involvement of grasp-related frontoparietal areas in online updating of grasp. Here, we leverage multivariate analyses of kinematic responses to novel perturbations of hand configuration and movement goals during grasping to dissociate the involvement of these areas in generation of forward models for hand shape versus integrating sensory information into the motor plan.