Coordination of intrinsic and extrinsic hand muscle activity as a function of wrist joint angle during two-digit grasping.
Coordination of intrinsic and extrinsic hand muscle activity as a function of wrist joint angle during two-digit grasping.
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DOI：
10.1016/j.neulet.2010.03.017
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发表时间：
2010-04-26
影响因子：
2.5
通讯作者：
Santello M
中科院分区：
文献类型：
--
作者：
Johnston JA;Bobich LR;Santello M
指尖力是由激活穿过手腕的肌肉以及起源和插入位于手内的肌肉（分别为手的外在和内在肌肉）引起的。因此，涉及腕关节角度变化的任务仅影响外部肌肉的力臂和长度，从而影响力产生能力。如果抓握任务需要施加恒定的指尖力，则中枢神经系统（CNS）可以通过仅将神经驱动调节到外在肌肉或内在肌肉或通过共同激活两组肌肉来响应手腕角度的变化。为了区分这些情况下，我们记录肌电图（EMG）活动的内在和外在的肌肉的拇指和食指作为手腕角度的函数在一个两个数字的对象举行的任务。我们假设腕关节角度的变化会引起手部肌肉的肌电振幅调制。在一个实验条件下，我们要求受试者在每个手腕角度施加相同的手指力量，而在第二个条件下，受试者可以选择手指力量来握住物体。肌电活动在外在和内在肌肉中作为腕角的函数被显著调制（均p < 0.05），但仅对于恒定力条件。此外，EMG调制是由所有肌肉的EMG幅度的均匀缩放引起的。我们的结论是，中枢神经系统控制外在和内在的肌肉作为一种肌肉协同作用。这些研究结果进行了讨论的协同作用和共同的神经输入跨运动核的手部肌肉的理论框架内。
Fingertip forces result from activation of muscles that cross the wrist and muscles whose origins and insertions reside within the hand (extrinsic and intrinsic hand muscles, respectively). Thus, tasks that involve changes in wrist angle affect the moment arm and length, hence the force-producing capabilities, of extrinsic muscles only. If a grasping task requires the exertion of constant fingertip forces, the Central Nervous System (CNS) may respond to changes in wrist angle by modulating the neural drive to extrinsic or intrinsic muscles only or by co-activating both sets of muscles. To distinguish between these scenarios, we recorded electromyographic (EMG) activity of intrinsic and extrinsic muscles of the thumb and index finger as a function of wrist angle during a two-digit object hold task. We hypothesized that changes in wrist angle would elicit EMG amplitude modulation of the extrinsic and intrinsic hand muscles. In one experimental condition we asked subjects to exert the same digit forces at each wrist angle, whereas in a second condition subjects could choose digit forces for holding the object. EMG activity was significantly modulated in both extrinsic and intrinsic muscles as a function of wrist angle (both p < 0.05) but only for the constant force condition. Furthermore, EMG modulation resulted from uniform scaling of EMG amplitude across all muscles. We conclude that the CNS controlled both extrinsic and intrinsic muscles as a muscle synergy. These findings are discussed within the theoretical frameworks of synergies and common neural input across motor nuclei of hand muscles.
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影响因子：
2.5
作者：
Johnston, JA;Winges, SA;Santello, M
通讯作者：
Santello, M
影响因子：
--
作者：
Bizzi, E.;Cheung, V. C. K.;Tresch, M.
通讯作者：
Tresch, M.
DOI：
10.1007/978-0-387-77064-2_31
发表时间：
2009-01-01
期刊：
PROGRESS IN MOTOR CONTROL: A MULTIDISCIPLINARY PERSPECTIVE
影响因子：
--
作者：
Johnston, Jamie A.;Winges, Sara A.;Santello, Marco
通讯作者：
Santello, Marco
影响因子：
2.5
作者：
Winges, SA;Santello, M
通讯作者：
Santello, M
影响因子：
2.4
作者：
Knutson, JS;Kilgore, KL;Crago, PE
通讯作者：
Crago, PE