Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.
Philos Trans R Soc Lond B Biol Sci. 2011 May 27;366(1570):1592-605. doi: 10.1098/rstb.2010.0367.
A neuromechanical approach to control requires understanding how mechanics alters the potential of neural feedback to control body dynamics. Here, we rewrite activation of individual motor units of a behaving animal to mimic the effects of neural feedback without concomitant changes in other muscles. We target a putative control muscle in the cockroach, Blaberus discoidalis (L.), and simultaneously capture limb and body dynamics through high-speed videography and a micro-accelerometer backpack. We test four neuromechanical control hypotheses. We supported the hypothesis that mechanics linearly translates neural feedback into accelerations and rotations during static postural control. However, during running, the same neural feedback produced a nonlinear acceleration control potential restricted to the vertical plane. Using this, we reject the hypothesis from previous work that this muscle acts primarily to absorb energy from the body. The conversion of the control potential is paralleled by nonlinear changes in limb kinematics, supporting the hypothesis that significant mechanical feedback filters the graded neural feedback for running control. Finally, we insert the same neural feedback signal but at different phases in the dynamics. In this context, mechanical feedback enables turning by changing the timing and direction of the accelerations produced by the graded neural feedback.
神经机械控制方法要求理解力学如何改变神经反馈控制身体动力学的潜力。在这里，我们重新编写了行为动物个体运动单位的激活，以模拟神经反馈的效果，而不会同时改变其他肌肉。我们以拟议的 Cockroach（Blaberus discoidalis（L.））控制肌肉为目标，并通过高速录像和微型加速度计背包同时捕捉肢体和身体动力学。我们测试了四个神经机械控制假设。我们支持这样的假设，即力学在线性上将神经反馈转化为静态姿势控制过程中的加速度和旋转。然而，在跑步过程中，相同的神经反馈产生了非线性加速度控制潜力，仅限于垂直平面。利用这一点，我们拒绝了之前的工作假设，即该肌肉主要作用是吸收身体的能量。控制潜力的转换与肢体运动学的非线性变化相平行，支持了这样的假设，即显著的机械反馈为跑步控制过滤了分级神经反馈。最后，我们在动力学中以不同的相位插入相同的神经反馈信号。在这种情况下，机械反馈通过改变分级神经反馈产生的加速度的时间和方向来实现转向。
