Appelberg B, Hulliger M, Johansson H, Sojka P
J Physiol. 1983 Feb;335:255-73. doi: 10.1113/jphysiol.1983.sp014532.
The reflex effects elicited by electrical stimulation of group II muscle afferent fibres were recorded with micro-electrodes in ninety-eight hind-limb gamma-motoneurones of cats anaesthetized with chloralose. Eighty-one of the gamma-cells were classified as either static or dynamic by means of stimulation in the mesencephalic area for dynamic control known to influence dynamic gamma-motoneurones selectively. A high responsiveness to activity in group II muscle fibres was found for the whole sample of gamma-cells. Group II muscle action on dynamic gamma-motoneurones was found to be more frequent than that on static ones. Excitation from group II fibres outweighed inhibition. This was clear cut for flexor gamma-motoneurones. In extensor gamma-cells, excitation prevailed by a small margin only. However, for both static and dynamic extensor gamma-cells, excitation prevailed from both posterior biceps--semitendinosus and the gastrocnemius--soleus nerves, whereas inhibition was more frequent from the deep peroneal and quadriceps nerves. All the reflex effects studied were likely to be mediated via oligosynaptic pathways. The shortest latencies of excitatory effects were compatible with a disynaptic coupling. The fastest inhibitions were presumably trisynaptic. The present findings, supported by a parallel study of reflexes evoked by group III muscle afferents, strongly suggest that the reflexes on gamma-motoneurones are not organized in accordance with the concept of flexion reflex afferents as conceived for alpha-motoneurones. The interpretation of the results suggests a particularly independent position for dynamic gamma-cells in relation to alpha- and static gamma-motoneurones. Hence, the results also furnish an argument against the concept of alpha-gamma linkage.
在用氯醛糖麻醉的猫的98个后肢γ运动神经元中，用微电极记录了电刺激Ⅱ类肌传入纤维所引发的反射效应。通过在中脑区域进行刺激以实现动态控制（已知该刺激可选择性地影响动态γ运动神经元），将81个γ细胞分类为静态或动态。发现整个γ细胞样本对Ⅱ类肌纤维的活动具有高反应性。发现Ⅱ类肌对动态γ运动神经元的作用比其对静态γ运动神经元的作用更频繁。来自Ⅱ类纤维的兴奋超过抑制。这在屈肌γ运动神经元中很明显。在伸肌γ细胞中，兴奋仅略占优势。然而，对于静态和动态伸肌γ细胞，来自后二头肌 - 半腱肌和腓肠肌 - 比目鱼肌神经的兴奋均占优势，而来自腓深神经和股四头肌神经的抑制更频繁。所有研究的反射效应可能是通过少突触途径介导的。兴奋效应的最短潜伏期与双突触耦合一致。最快的抑制作用大概是三突触的。由对Ⅲ类肌传入纤维引发的反射的平行研究支持的当前发现，强烈表明对γ运动神经元的反射并非按照为α运动神经元所设想的屈肌反射传入概念来组织。结果的解释表明动态γ细胞相对于α和静态γ运动神经元具有特别独立的地位。因此，这些结果也为反对α - γ联动概念提供了一个论据。
