Force dynamics and synergist muscle activation in stick insects: the effects of using joint torques as mechanical stimuli.
Force dynamics and synergist muscle activation in stick insects: the effects of using joint torques as mechanical stimuli.
复制标题
竹节虫的力动力学和增效肌肉激活：使用关节扭矩作为机械刺激的效果
DOI：
10.1152/jn.00371.2018
复制
发表时间：
2018
影响因子：
2.5
通讯作者：
Schmitz J
中科院分区：
文献类型：
--
作者：
Zill SN;Dallmann CJ;Büschges A;Chaudhry S;Schmitz J
许多感觉系统都针对特定的行为参数进行调整，并具有特定于任务的效果。我们研究了力反馈如何促进竹节虫连续同源腿中增效肌的激活。使用传统的半正弦或斜坡和保持功能施加力。我们还利用了根据自由行走动物实验计算出的关节扭矩波形。在所有腿中，施加到跗骨（脚）或近端腿节（转子）的力激活了产生基底抓握和支撑的增效肌，但前腿中降压肌与跗骨力的耦合较弱。当诱导动物寻求基质抓握时，使用斜坡和保持功能激活转子受体会对所有腿部的降压肌产生正反馈。然而，增效屈肌的放电在中等力量水平下表现出适应。相比之下，使用没有静态保持阶段的扭矩波形施加力，在肌肉协同作用中产生持续放电，几乎没有适应。发射频率反映了地面反作用力的大小，根据力幅度的变化进行分级，并且还可以通过添加到波形中的瞬态力扰动进行调制。通过扭矩、斜坡和保持功能对增效剂激活的比较揭示了力动力学 (dF/dt) 的强烈影响。这些研究支持这样的观点，即力感受器可以根据其在行为中的具体用途，将肌肉协同作用同步调整到每条腿中发生的力大小和动力学范围。新的和值得注意的力感受器（钟状感器）对腿部肌肉和协同作用的影响在竹节虫中使用斜坡和保持函数以及通过逆动力学计算的关节扭矩波形进行了表征。运动反应得以维持，并且对更“自然”和非线性扭矩刺激的适应能力降低。扭矩波形的一阶导数 (dF/dt) 的计算表明，这种差异与系统的动态灵敏度相关。
Many sensory systems are tuned to specific parameters of behaviors and have effects that are task-specific. We have studied how force feedback contributes to activation of synergist muscles in serially homologous legs of stick insects. Forces were applied using conventional half-sine or ramp and hold functions. We also utilized waveforms of joint torques calculated from experiments in freely walking animals. In all legs, forces applied to either the tarsus (foot) or proximal leg segment (trochanter) activated synergist muscles that generate substrate grip and support, but coupling of the depressor muscle to tarsal forces was weak in the front legs. Activation of trochanteral receptors using ramp and hold functions generated positive feedback to the depressor muscle in all legs when animals were induced to seek substrate grip. However, discharges of the synergist flexor muscle showed adaptation at moderate force levels. In contrast, application of forces using torque waveforms, which do not have a static hold phase, produced sustained discharges in muscle synergies with little adaptation. Firing frequencies reflected the magnitude of ground reaction forces, were graded to changes in force amplitude, and could also be modulated by transient force perturbations added to the waveforms. Comparison of synergist activation by torques and ramp and hold functions revealed a strong influence of force dynamics (dF/dt). These studies support the idea that force receptors can act to tune muscle synergies synchronously to the range of force magnitudes and dynamics that occur in each leg according to their specific use in behavior.NEW & NOTEWORTHYThe effects of force receptors (campaniform sensilla) on leg muscles and synergies were characterized in stick insects using both ramp and hold functions and waveforms of joint torques calculated by inverse dynamics. Motor responses were sustained and showed reduced adaptation to the more “natural” and nonlinear torque stimuli. Calculation of the first derivative (dF/dt) of the torque waveforms demonstrated that this difference was correlated with the dynamic sensitivities of the system.
登录
查看更多内容
姿势和运动的负载传感和控制。
影响因子：
2
作者：
S. Zill;J. Schmitz;A. Büschges
通讯作者：
A. Büschges
竹节虫 Carausius morosus 的胫骨钟状感器编码力的增加和减少
DOI：
10.1007/s00359-011-0647-4
发表时间：
2011
期刊：
Journal of Comparative Physiology A
影响因子：
--
作者：
S. Zill;A. Büschges;J. Schmitz
通讯作者：
J. Schmitz
影响因子：
3.2
作者：
Duysens J;De Groote F;Jonkers I
通讯作者：
Jonkers I
昆虫的适应性运动行为
影响因子：
5.7
作者：
R. Ritzmann;A. Büschges
通讯作者：
A. Büschges
竹节虫腿部的力编码描绘了运动控制的参考系。
影响因子：
2.5
作者：
S. Zill;J. Schmitz;Sumaiya Chaudhry;A. Büschges
通讯作者：
A. Büschges