Department of Movement Physiology, A.A. Bogomoletz Institute of Physiology, National Academy of Sciences, Bogomoletz Str. 4, Kiev, 01024, Ukraine.
Exp Brain Res. 2012 Oct;222(4):399-414. doi: 10.1007/s00221-012-3227-0. Epub 2012 Aug 29.
The experiments presented here and performed in anaesthetized cats aimed at studying the dynamics of interactions between antagonist muscle groups. The tendons of triceps surae muscles of both hindlimbs were connected with an artificial joint (a pulley installed on a shaft). The muscles were activated by the distributed stimulation of five filaments of cut ventral roots L7-S1 on both sides of the spinal cord; movements were evoked by the rate-modulation of the stimulation trains. The study mostly compared programs of reciprocal activation and co-activation, including different changes in stimulation rates of muscle antagonists. The most common feature of the movements in both activation modes was hysteresis of the joint angle changes in dependence on stimulus rate. Reciprocal activation appeared suitable for a precise regulation of both amplitude and velocity of the movements in direction of the agonist shortening; maximal effectiveness was achieved during full switching off the antagonist stimulation at plateaus of the movement traces. The reverse movements during decrease of the agonist's stimulation rate demonstrated an explicit nonlinear form with pronounced initial phase of the joint angle fixation. The co-activation pattern distinctly reduced the hysteresis of joint movements and suppressed the stimulation after-effects, such as the lasting residual movements after fixation of the stimulation rates.
本文介绍了在麻醉猫身上进行的实验，旨在研究拮抗肌群之间相互作用的动力学。双侧后肢的比目鱼肌肌腱通过人工关节（安装在轴上的滑轮）相连。肌肉通过脊髓两侧 L7-S1 切断的五个神经根纤维的分布刺激来激活；通过刺激列车的频率调制来引发运动。该研究主要比较了交互激活和共同激活的方案，包括肌肉拮抗剂刺激频率的不同变化。在这两种激活模式下，运动的最常见特征是关节角度变化对刺激频率的滞后。在运动轨迹的平台上完全关闭拮抗剂刺激时，交互激活适用于精确调节运动的幅度和速度；在这种情况下，可获得最大的效果。在降低激动剂刺激频率时，反向运动表现出明显的非线性形式，具有明显的初始关节角度固定相位。共同激活模式明显降低了关节运动的滞后，并抑制了刺激后效应，例如在刺激频率固定后持续的残留运动。
