Common input to motor units of digit flexors during multi-digit grasping
Common input to motor units of digit flexors during multi-digit grasping
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DOI：
10.1152/jn.00516.2004
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发表时间：
2004-12-01
影响因子：
2.5
通讯作者：
Santello, M
中科院分区：
文献类型：
--
作者：
Winges, SA;Santello, M
全手抓取的控制依赖于多种力的复杂协调。虽然许多研究的特点是协调手指的力量和扭矩，控制手部肌肉活动的基础上，多指抓取还没有研究到相同的程度。手指肌肉或肌肉间室的运动单元同步性可能是手指力有限个性化的因素之一。然而，当需要高水平的力耦合以防止在抓握期间物体滑动时，手指力之间的这种“不期望的”耦合可能是期望的。本研究的目的是量化的力量之间的同步运动单位从外在的手肌肉作为受试者举行了一个设备与五个数字的把握。在保持阶段，我们记录了每个手指施加的法向力和单个运动单位的电活动，每个四个部门的肌肉屈趾深肌（FDP）和一个拇指屈肌，m。拇长屈肌（FPL）。运动单位同步性的强度由共同输入强度指数（CIS）量化。我们发现FPL和指数FDP隔室[CIS：0.49+/-0.03（SE）]之间以及大多数FDP隔室（0.34+/-0.02）之间存在中度至强烈的运动单位同步性。然而，在FPL与中指、无名指和小指FDP隔室之间发现弱同步性（0.25+/-0.01）。这种差异可能反映了在五指抓握中拇指-食指对相对于其他拇指-手指组合的更大的力贡献。
The control of whole hand grasping relies on complex coordination of multiple forces. While many studies have characterized the coordination of finger forces and torques, the control of hand muscle activity underlying multi-digit grasping has not been studied to the same extent. Motor-unit synchrony across finger muscles or muscle compartments might be one of the factors underlying the limited individuation of finger forces. Such "unwanted" coupling among finger forces, however, might be desirable when a high level of force coupling is required to prevent object slip during grasping. The goal of this study was to quantify the strength of synchrony between single motor units from extrinsic hand muscles as subjects held a device with a five-digit grasp. During the hold phase, we recorded the normal force exerted by each digit and the electrical activity of single motor units from each of the four divisions of the muscle flexor digitorum profundus (FDP) and one thumb flexor muscle, m. flexor pollicis longus (FPL). The strength of motor-unit synchrony was quantified by the common input strength index (CIS). We found moderate to strong motor-unit synchrony between FPL and the index FDP compartment [CIS: 0.49+/-0.03 (SE)] and across most FDP compartments (0.34+/-0.02). Weak synchrony, however, was found between FPL and the middle, ring, and little finger FDP compartments (0.25+/-0.01). This difference might reflect the larger force contribution of the thumb-index finger pair relative to other thumb-finger combinations in five-digit grasping.