Garland S J, Griffin L
School of Physical Therapy and Department of Physiology, Elborn College, University of Western Ontario, London, Ontario, N6G 1H1 Canada.
Can J Appl Physiol. 1999 Apr;24(2):113-30. doi: 10.1139/h99-010.
Motor unit double discharges, or doublets, have been described as two consecutive motor unit discharges that occur with a short interspike interval of 2.5 - 20 ms (Simpson, 1969). Double discharges have been reported in the literature for over 70 years. For instance, Eccles and Hoff (1932) found that double discharges were elicited occasionally at the onset of a crossed extension reflex in the soleus muscle of the anaesthetized cat. With the use of electrical stimulation protocols, short interspike intervals inserted at the beginning of a stimulation train have been shown to increase both the peak force and rate of rise of force production, and also decrease the range of fatigue. The extent to which double discharges occur in naturally-occurring voluntary behaviours remains relatively unexplored. This review examines the issue of whether double discharges occur solely because of an intrinsic property of motoneurones, thereby representing a "statistical anomaly," or whether they may result from a neural control strategy to augment force production, i.e., a "functional entity."
运动单位双发放，即双重放电，被描述为两个连续的运动单位放电，其放电间隔很短，为2.5 - 20毫秒（辛普森，1969年）。双重放电在文献中已有70多年的报道。例如，埃克尔斯和霍夫（1932年）发现，在麻醉猫的比目鱼肌交叉伸展反射开始时偶尔会引发双重放电。通过使用电刺激方案，已表明在刺激序列开始时插入的短放电间隔会增加峰值力和力产生的上升速率，并且还会减小疲劳范围。双重放电在自然发生的自愿行为中出现的程度仍相对未被探索。本综述探讨了双重放电是否仅仅由于运动神经元的内在特性而发生，从而代表一种“统计异常”，或者它们是否可能源于增强力产生的神经控制策略，即一种“功能实体”。
