Biomedical Engineering Department, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 84105, Israel.
J Neurophysiol. 2010 Jun;103(6):3017-26. doi: 10.1152/jn.00939.2009. Epub 2010 Mar 31.
Proximal and distal muscles are different in size, maximum force, mechanical action, and neuromuscular control. In the current study we explore the perception of delayed stiffness when probing is executed using movement of different joints. We found a proximodistal gradient in the amount of underestimation of delayed stiffness in the transition between probing with shoulder, elbow, and wrist joints. Moreover, there was a similar gradient in the optimal weighting between estimation of stiffness and the inverse of estimation of compliance that predicted the perception of the subjects. These gradients could not be ascribed to differences in movement amplitude, duration, velocity, and force amplitude because these variables were not significantly modulated by the joint used for probing. Mean force did not follow a similar gradient either. Therefore we suggest that the observed gradient in perception reveals a proximodistal gradient in control, such that proximal joints are dominated by force control, whereas distal joints are dominated by position control.
近侧和远侧肌肉在大小、最大力、机械作用和神经肌肉控制方面存在差异。在本研究中，我们探讨了在使用不同关节运动进行探测时，对延迟刚度的感知。我们发现，在从肩部、肘部和腕部关节进行探测的转换过程中，对延迟刚度的低估程度存在近侧到远侧的梯度。此外，在对刚度的估计和对顺应性的估计的倒数之间的最佳加权方面也存在类似的梯度，这预测了被试的感知。这些梯度不能归因于运动幅度、持续时间、速度和力幅度的差异，因为这些变量不受用于探测的关节的显著调节。平均力也没有遵循类似的梯度。因此，我们认为观察到的感知梯度揭示了控制的近侧到远侧梯度，即近端关节主要受力控制，而远端关节主要受位置控制。
