Hansen N L, Hansen S, Christensen L O, Petersen N T, Nielsen J B
Division of Neurophysiology, Department of Medical Physiology, The Panum Institute, Copenhagen University, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
J Neurophysiol. 2001 Sep;86(3):1266-76. doi: 10.1152/jn.2001.86.3.1266.
Synchronization of motor unit activity was investigated during treadmill walking (speed: 3-4 km/h) in 25 healthy human subjects. Recordings were made by pairs of wire electrodes inserted into the tibialis anterior (TA) muscle and by pairs of surface electrodes placed over this muscle and a number of other lower limb muscles (soleus, gastrocnemius lateralis, gastrocnemius medialis, biceps femoris, vastus lateralis, and vastus medialis). Short-lasting synchronization (average duration: 9.6 +/- 1.1 ms) was observed between spike trains generated from multiunit electromyographic (EMG) signals recorded by the wire electrodes in TA in eight of nine subjects. Synchronization with a slightly longer duration (12.8 +/- 1.2 ms) was also found in 13 of 14 subjects for paired TA surface EMG recordings. The duration and size of this synchronization was within the same range as that observed during tonic dorsiflexion in sitting subjects. There was no relationship between the amount of synchronization and the speed of walking. Synchronization was also observed for pairs of surface EMG recordings from different ankle plantarflexors (soleus, medial gastrocnemius, and lateral gastrocnemius) and knee extensors (vastus lateralis and medialis of quadriceps), but not or rarely for paired recordings from ankle and knee muscles. The data demonstrate that human motor units within a muscle as well as synergistic muscles acting on the same joint receive a common synaptic drive during human gait. It is speculated that the common drive responsible for the motor unit synchronization during gait may be similar to that responsible for short-term synchronization during tonic voluntary contraction.
在25名健康人体受试者以3 - 4千米/小时的速度在跑步机上行走时，对运动单位活动的同步性进行了研究。通过插入胫骨前肌（TA）的一对线状电极以及置于该肌肉和其他一些下肢肌肉（比目鱼肌、外侧腓肠肌、内侧腓肠肌、股二头肌、股外侧肌和股内侧肌）上的一对表面电极进行记录。在9名受试者中的8名中，观察到由TA中线状电极记录的多单位肌电图（EMG）信号产生的尖峰序列之间存在短暂同步（平均持续时间：9.6±1.1毫秒）。在14名受试者中的13名中，对于配对的TA表面EMG记录也发现了持续时间稍长（12.8±1.2毫秒）的同步。这种同步的持续时间和大小与坐位受试者在强直性背屈期间观察到的范围相同。同步量与步行速度之间没有关系。对于来自不同踝跖屈肌（比目鱼肌、内侧腓肠肌和外侧腓肠肌）和膝伸肌（股四头肌的股外侧肌和股内侧肌）的表面EMG记录对也观察到了同步，但对于来自踝部和膝部肌肉的配对记录则没有或很少观察到同步。数据表明，肌肉内以及作用于同一关节的协同肌肉中的人类运动单位在人类步态期间接受共同的突触驱动。据推测，负责步态期间运动单位同步的共同驱动可能与负责强直性随意收缩期间短期同步的驱动相似。
