Cheney P D, Preston J B
J Neurophysiol. 1976 Jan;39(1):9-19. doi: 10.1152/jn.1976.39.1.9.
The classification and distinguishing characteristics of fusimotor fibres of the baboon soleus muscle have been studied by determining the effects of single fusimotor fiber stimulation on the response of isolated spindle afferents to muscle stretch. As in the cat, fusimotor fibres in the baboon were divisible into static and dynamic types on the basis of the effect of their stimulation at 200/s on the dynamic index of the primary afferent. Single fusimotor fibres had the same qualitative effect-static or dynamic-on all the primary afferents they were found to influence. All static fusimotor fibres produced at least 1 to 1 driving of primary afferent discharge at 50/s if the muscle length was adjusted to optimize conditions for driving. In contrast, 31 of 32 dynamic fusimotor fibres did not produce driving of primary afferent discharge even though all were studied at many different muscle lengths and frequencies of stimulation. Therefore, fusimotor fibres in the baboon could be classified as static or dynamic on the basis of their ability to produce driving of the primary afferent. The ratio of isolated static to dynamic fusimotor fibers was 1.5 to 1. The mean conduction velocity of static fusimotor fibers was 24.1 m/s and that of dynamics was 20.2 m/s. Although the difference between these two means was statistically significant (P less than 0.001), the conduction velocity histograms of static and dynamic fusimotors overlapped, precluding classification by this means. Secondary afferents with one possible exception were concluded to be exclusively activated by static fusimotor fibers. Poststimulus effects of fusimotor stimulation on primary afferent response to stretch were studied. With intervals between the end of stimulation and the beginning of stretch of 0.1 s, dynamic fusimotor stimulation produced facilitation of the primary afferent response to stretch, whereas static fusimotor fibers produced depression.
通过测定单根肌梭运动纤维刺激对分离的肌梭传入纤维对肌肉拉伸反应的影响，研究了狒狒比目鱼肌肌梭运动纤维的分类及鉴别特征。与猫一样，根据在200次/秒刺激时其对初级传入纤维动态指数的影响，狒狒的肌梭运动纤维可分为静态和动态两类。单根肌梭运动纤维对其所影响的所有初级传入纤维具有相同的定性作用——静态或动态。如果调整肌肉长度以优化驱动条件，所有静态肌梭运动纤维在50次/秒时至少产生1:1的初级传入放电驱动。相反，32根动态肌梭运动纤维中的31根即使在许多不同的肌肉长度和刺激频率下进行研究，也未产生初级传入放电驱动。因此，根据其产生初级传入驱动的能力，狒狒的肌梭运动纤维可分为静态或动态。分离的静态与动态肌梭运动纤维的比例为1.5:1。静态肌梭运动纤维的平均传导速度为24.1米/秒，动态肌梭运动纤维的平均传导速度为20.2米/秒。尽管这两个平均值之间的差异具有统计学意义（P小于0.001），但静态和动态肌梭运动纤维的传导速度直方图重叠，无法以此方式进行分类。除了一个可能的例外，次级传入纤维被认为仅由静态肌梭运动纤维激活。研究了肌梭运动纤维刺激对初级传入纤维拉伸反应的刺激后效应。在刺激结束与拉伸开始之间的间隔为0.1秒时，动态肌梭运动纤维刺激产生对初级传入纤维拉伸反应的易化作用，而静态肌梭运动纤维产生抑制作用。
