Patel Vrajeshri, Burns Martin, Vinjamuri Ramana
Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
Med Biol Eng Comput. 2016 Aug;54(8):1217-27. doi: 10.1007/s11517-015-1424-2. Epub 2015 Dec 11.
The human hand uses a combination of feedforward and feedback mechanisms to accomplish high degree of freedom in grasp control efficiently. In this study, we used a synergy-based control model to determine the effect of sensory feedback on kinematic synergies in the grasping hand. Ten subjects performed two types of grasps: one that included feedback (real) and one without feedback (memory-guided), at two different speeds (rapid and natural). Kinematic synergies were extracted from rapid real and rapid memory-guided grasps using principal component analysis. Synergies extracted from memory-guided grasps revealed greater preservation of natural inter-finger relationships than those found in corresponding synergies extracted from real grasps. Reconstruction of natural real and natural memory-guided grasps was used to test performance and generalizability of synergies. A temporal analysis of reconstruction patterns revealed the differing contribution of individual synergies in real grasps versus memory-guided grasps. Finally, the results showed that memory-guided synergies could not reconstruct real grasps as accurately as real synergies could reconstruct memory-guided grasps. These results demonstrate how visual and tactile feedback affects a closed-loop synergy-based motor control system.
人类的手运用前馈和反馈机制的组合，以有效地实现抓握控制中的高度自由度。在本研究中，我们使用了一种基于协同作用的控制模型来确定感觉反馈对抓握手中运动协同作用的影响。十名受试者以两种不同速度（快速和自然）进行两种抓握：一种包含反馈（真实抓握），另一种无反馈（记忆引导抓握）。使用主成分分析从快速真实抓握和快速记忆引导抓握中提取运动协同作用。从记忆引导抓握中提取的协同作用显示，与从真实抓握中提取的相应协同作用相比，手指间自然关系的保留程度更高。利用自然真实抓握和自然记忆引导抓握的重建来测试协同作用的性能和通用性。对重建模式的时间分析揭示了个体协同作用在真实抓握与记忆引导抓握中的不同贡献。最后，结果表明，记忆引导协同作用无法像真实协同作用重建记忆引导抓握那样准确地重建真实抓握。这些结果证明了视觉和触觉反馈如何影响基于闭环协同作用的运动控制系统。
