Kudina L P, Andreeva R E
Biofizika. 2005 Sep-Oct;50(5):894-900.
The excitability of firing motoneurones activated by voluntary contraction of the flexor carpi ulnaris or tibialis anterior was tested by single excitatory Ia afferent volleys. In order to estimate the stimulation effects, the peri-stimulus time histograms of single motoneurones were plotted, and the firing indices were calculated. It was shown that the firing-frequency effect was absent within the range of 4-14 imp/s during testing by low-intensity excitatory volley. At higher intensity of afferent volley, the excitability increased at a low firing rate. It is suggested that the characteristics of the interspike-interval excitability trajectories underlie these relations. These findings made it possible to explicate some conflicting literature data which were usually reported without taking the afferent volley intensity effect into account. The mechanisms controlling the firing motoneurone excitability and possible trajectories of interspike-interval membrane potential in human motoneurones are discussed.
通过单一兴奋性Ia传入冲动，测试了尺侧腕屈肌或胫前肌随意收缩激活的运动神经元的兴奋性。为了评估刺激效果，绘制了单个运动神经元的刺激时间直方图，并计算了放电指数。结果表明，在低强度兴奋性冲动测试期间，4-14次冲动/秒范围内不存在放电频率效应。在较高强度的传入冲动下，低放电率时兴奋性增加。有人认为，峰间间隔兴奋性轨迹的特征是这些关系的基础。这些发现使得解释一些通常未考虑传入冲动强度效应而报道的相互矛盾的文献数据成为可能。本文讨论了控制人类运动神经元放电兴奋性的机制以及峰间间隔膜电位的可能轨迹。
