Periodic modulation of motor-unit activity in extrinsic hand muscles during multidigit grasping
Periodic modulation of motor-unit activity in extrinsic hand muscles during multidigit grasping
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DOI：
10.1152/jn.01134.2004
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发表时间：
2005-07-01
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;Winges, SA;Santello, M
我们最近检查了手指屈肌运动单位在多手指抓握过程中接收共同输入的程度。这项任务引发了跨肌肉（指深屈肌，FDP 和拇长屈肌，FPL）和跨 FDP 肌肉室的中度至强运动单位同步性（共同输入强度，CIS），尽管这种共同输入的强度在数字对之间并不均匀。为了进一步表征控制多手指抓取的神经机制，我们通过计算相干性分析了频域中这些手部肌肉的单个运动单元的发射之间的关系。我们报告了三个主要发现。首先，与内在手部肌肉中报道的情况相反，属于不同肌肉和外在指屈肌肌肉室的运动单位在0至5和5至10Hz频率范围内表现出显着的一致性，而在较高的10-20Hz范围内表现出较弱的一致性（最大分别为0.0025和0.0008，在所有FDP室对中汇集）。其次，数字对之间的一致性强度和发生率差异很大。第三，与文献报道的相反，肌肉间的一致性可能比肌肉内的一致性更强、更普遍，因为 FPL-FDP2（拇指-食指数字对）在我们的数据中表现出最强和最普遍的一致性（3 Hz 时分别为 0.010 和 43%）。讨论了这些肌肉和肌肉区室的共同输入的异质组织，以及各个手指对在协调多个手指力的抓握中的功能作用。
We recently examined the extent to which motor units of digit flexor muscles receive common input during multidigit grasping. This task elicited moderate to strong motor-unit synchrony (common input strength, CIS) across muscles (flexor digitorum profundus, FDP, and flexor pollicis longus, FPL) and across FDP muscle compartments, although the strength of this common input was not uniform across digit pairs. To further characterize the neural mechanisms underlying the control of multidigit grasping, we analyzed the relationship between firing of single motor units from these hand muscles in the frequency domain by computing coherence. We report three primary findings. First, in contrast to what has been reported in intrinsic hand muscles, motor units belonging to different muscles and muscle compartments of extrinsic digit flexors exhibited significant coherence in the 0- to 5- and 5- to 10-Hz frequency ranges and much weaker coherence in the higher 10-20 Hz range (maximum 0.0025 and 0.0008, respectively, pooled across all FDP compartment pairs). Second, the strength and incidence of coherence differed considerably across digit pairs. Third, contrary to what has been reported in the literature, across-muscle coherence can be stronger and more prevalent than within-muscle coherence, as FPL-FDP2 (thumb-index digit pair) exhibited the strongest and most prevalent coherence in our data (0.010 and 43% at 3 Hz, respectively). The heterogeneous organization of common input to these muscles and muscle compartments is discussed in relation to the functional role of individual digit pairs in the coordination of multiple digit forces in grasping.