Cheney P D, Preston J B
J Neurophysiol. 1976 Jan;39(1):20-30. doi: 10.1152/jn.1976.39.1.20.
The effects of stimulation of single static and dynamic fusimotor fibers on the dynamic sensitivity and position sensitivity of primary and secondary spindle afferents have been studied in the soleus muscle of the baboon. Static fusimotor fibers decreased the mean dynamic sensitivity of primary afferents at all rates of stretch and stimulation. The magnitude of the decrease in dynamic sensitivity increased as the rate of fusimotor stimulation was increased. Qualitatively similar effects were observed in secondary afferents. Static fusimotor stimulation had a strong excitatory effect on spindle afferent resting discharge and greatly increased the mean position sensitivity of both primary and secondary afferents. Dynamic fusimotor fibers increased the mean dynamic index of primary afferents at all rates of stretch and stimulation. The effect of dynamic fusimotor fibers on the mean dynamic sensitivity, however, was dependent on the rate of muscle stretch; at rates below 15 mm/s the dynamic sensitivity was substantially increased, whereas at rates greater than 15 mm/s it was either unchanged or decreased. Dynamic fusimotor fibers slightly decreased the mean position sensitivity of primary afferents.
在狒狒的比目鱼肌中，研究了单一静态和动态肌梭运动纤维的刺激对初级和次级肌梭传入纤维的动态敏感性和位置敏感性的影响。静态肌梭运动纤维在所有拉伸和刺激速率下均降低了初级传入纤维的平均动态敏感性。随着肌梭运动刺激速率的增加，动态敏感性降低的幅度增大。在次级传入纤维中观察到定性相似的效应。静态肌梭运动刺激对肌梭传入纤维的静息放电有强烈的兴奋作用，并大大增加了初级和次级传入纤维的平均位置敏感性。动态肌梭运动纤维在所有拉伸和刺激速率下均增加了初级传入纤维的平均动态指数。然而，动态肌梭运动纤维对平均动态敏感性的影响取决于肌肉拉伸速率；在低于15毫米/秒的速率下，动态敏感性大幅增加，而在大于15毫米/秒的速率下，它要么不变，要么降低。动态肌梭运动纤维略微降低了初级传入纤维的平均位置敏感性。
