Advancing the understanding of fundamental principles of motor control.

拟议的项目建立在我们在以前的NSERC资助任期内取得的几项主要成就的基础上。(1)发现皮质脊髓系统，而不是直接向肌肉编程运动学和运动指令，设置和重置身体部位的阈值位置，适当的肌肉开始被招募（Raptis et al. 2010）。(2)皮质脊髓通路介导的阈值位置控制不仅是常规运动动作的基础，也是预期运动动作的基础（Sangani et al. 2011）。(3)阈值位置控制的概念已被推广到多肌肉和多关节对运动动作的控制（人类的手臂伸展、跳跃、跳舞和行走；Feldman et al. 2011）。(4)解决了运动控制中的几个经典问题，如姿态运动问题和多肌肉、多关节控制中的冗余问题（Feldman 2011）。(5)我们确定中风后受试者的虚弱和痉挛是由于阈臂位置的中枢调节缺陷造成的，并详细设计了一种诊断装置来帮助临床医生识别这些缺陷（Patent, Feldman et al. 2006）。(6)我们的多学科团队已经开发了大量的专业知识，不仅可以模拟单个身体运动，还可以模拟整个身体运动，并通过实验测试了这些模型的预测（Pilon等人，2005年，2006年；Feldman等人，2007年；Latash等人，2010年；Gorniak等人，2010年；Yang和Feldman 2010年；Feldman 2011年）。在该计划中，我们将分析皮质脊髓系统如何使用阈值位置重置来控制环境中不同位置的非自愿（卸载反射），预期（手臂的自我卸载）和自愿到达物体。运动控制的基本原理将通过全身运动（从坐到站，然后跳跃，行走和跑步）的数值模拟来验证。该项目旨在对复杂运动是如何被集中控制的理解做出重大贡献，这将用于精心设计几种设备，以帮助临床医生在中风后多肌肉协调神经功能缺陷的患者康复。

The proposed program has been built on our several major achievements under the tenure of the previous NSERC grants. (1) The discovery that the corticospinal system, rather than directly programming kinematics and motor commands to muscles, sets and resets the threshold position of body segments at which appropriate muscles begin to be recruited (Raptis et al. 2010). (2) Threshold position control mediated by corticospinal pathways underlies not only regular but also anticipatory motor actions (Sangani et al. 2011). (3) The notion of threshold position control has been generalized to multi-muscle and multi-joint control of motor actions (arm reaching, jumping, dancing, and walking in humans; Feldman et al. 2011). (4) Several classical problems in motor control has been solved, such as the posture-movement problem and the redundancy problems in multi-muscle and multi-joint control (Feldman 2011). (5)We established that weakness and spasticity in post-stroke subjects result from deficits in the central regulation of the threshold arm position and elaborated a diagnostic device to help clinicians in identifying these deficits (Patent, Feldman et al. 2006). (6) Our multidisciplinary team has developed a substantial expertise in modeling of not only single- but also whole body movements and experimentally tested predictions of these models (Pilon et al. 2005, 2006; Feldman et al. 2007; Latash et al. 2010; Gorniak et al. 2010; Yang and Feldman 2010; Feldman 2011). In the proposed program, we will analyze how the corticospinal system uses threshold position resetting to control involuntary (unloading reflex), anticipatory (self-unloading of the arm) and voluntary reaching for an object at different locations in the environment. The fundamental principles of motor control will be validated by numerical simulations of whole body movements (sit-to-stand then jump, walk and run). The program is intended to substantially contribute to the understanding of how complex movements are centrally controlled, which will be used in elaborating several devices to help clinicians in rehabilitation of post-stroke subjects with neurological deficits in the multi-muscle coordination.