THE AFFERENT VOLLEYS RESPONSIBLE FOR SPINAL PROPRIOCEPTIVE REFLEXES IN MAN
THE AFFERENT VOLLEYS RESPONSIBLE FOR SPINAL PROPRIOCEPTIVE REFLEXES IN MAN
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DOI：
10.1113/jphysiol.1983.sp014732
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发表时间：
1983-01-01
影响因子：
5.5
通讯作者：
MCKEON, B
中科院分区：
文献类型：
--
作者：
BURKE, D;GANDEVIA, SC;MCKEON, B
为了确定引起跟腱抽搐和H反射的神经截击，通过经皮插入腘窝胫骨神经的适当神经束的微电极记录肌肉传入活动。比目鱼肌传入神经对肌腱冲击的反应是分散的，在冲击后3.5-7.0 ms开始，在6.5-11.0 ms时达到峰值，持续25-30 ms，这取决于冲击的强度。对坐骨神经的电刺激水平足以引起H反射，但对M波的阈值以下产生更同步的波，其中最快的纤维传导速度为62-67米/秒，最慢的为36-45米/秒。踝关节震动阈下产生的加速度波以超过150m /s的速度沿皮肤传播。腓肠肌腹部之间的中间是一个有4-5个不同相位和最大振幅的阻尼振荡。是跟腱的1/20。在10个主要纺锤末梢的情况下，踝关节抽搐时的肌腱敲击阈下电位每次触发2-5个尖峰放电，最短的尖峰间隔为4-7 ms。肌腱撞击引起2个高尔基肌腱器官的单次放电，并改变了单个次级纺锤体末端的放电模式。多单元肌传入齐射的分散程度可以用初级纺锤末梢的放电模式来解释。从支配长屈肌、后胫肌、足部固有肌和足部皮肤的神经束记录来看，对跟腱的撞击引起了清晰的传入截击。对腘窝胫神经施加足以引起比目鱼肌H反射的电刺激，产生足部固有肌肉的肌肉传入信号或足部皮肤传入信号的截击。当踝关节背屈105度时，H反射被抑制，跟腱抽搐增强。90.度。通过对比目鱼肌自主激活的单个运动单元放电的刺激后时间直方图估计电刺激、H反射和踝关节抽搐时肌腱敲击阈下产生的比目鱼肌运动神经元兴奋性突触后电位（epsp）上升时间的持续时间。电刺激的平均epsp上升时间为1.9 ms，肌腱敲击的平均epsp上升时间为6.6 ms。有证据表明，电诱发的epsp持续时间被抑制性突触后电位（ipsp）缩短，其潜伏期仅略长于epsp。在Ia组三头肌表面传入的机械诱导和电诱导的齐射不是均匀的齐射。传入截击在许多方面都不同，因此将H反射和肌腱抽搐作为一种测量梭状运动活动的方法进行比较可能是无效的。这两种反射都不能被认为是纯粹的单突触反射。
To define the neural volleys responsible for the Achilles tendon jerk and the H reflex, muscle afferent activity was recorded using micro-electrodes inserted percutaneously into appropriate fascicles of the tibial nerve in the popliteal fossa. The response of soleus muscle afferents to tendon percussion consisted of a dispersed volley, starting 3.5-7.0 ms after percussion, increasing to a peak over 6.5-11.0 ms, and lasting 25-30 ms, depending on the strength of percussion. Electrical stimuli to the sciatic nerve at a level adequate to evoke an H reflex but subthreshold for the M wave produced a more synchronized volley, the fastest fibers of which had conduction velocities of 62-67 m/s, and the slowest 36-45 m/s. The wave of acceleration produced by percussion subthreshold for the ankle jerk spread along the skin at over 150 m/s. Midway between the bellies of the gastrocnemii is consisted of a damped oscillation with 4-5 separate phases and maximum amplitude .apprx. 1/20 of that recorded on the Achilles tendon. With 10 primary spindle endings, tendon percussion subthreshold for the ankle jerk elicited 2-5 spike discharges per tap, the shortest interspike intervals being 4-7 ms. Tendon percussion elicited single discharges from 2 Golgi tendon organs, and altered the discharge pattern of a single secondary spindle ending. The degree of dispersion of the multi-unit muscle afferent volley can be explained by the pattern of discharge of primary spindle endings. Percussion on the Achilles tendon evoked crisp afferent volleys in recordings from nerve fascicles innervating flexor hallucis longus, tibialis posterior, the intrinsic muscles of the foot and the skin of the foot. Electrical stimuli delivered to the tibial nerve in the popliteal fossa at a level sufficient for the H reflex of soleus produced either a volley in muscle afferents from the intrinsic muscles of the foot or a volley in cutaneous afferents from the foot. For comparable stimuli in the 2 positions, the H reflex was inhibited but the Achilles tendon jerk enhanced when the ankle was dorsiflexed from 105.degree. to 90.degree.. The duration of the rise times of the excitatory post-synaptic potentials (epsp) produced in soleus motoneurons by electrical stimulation, and by tendon percussion subthreshold for the H reflex and the ankle jerk respectively, was estimated from post-stimulus time histograms of the discharge of voluntarily activated single motor units in soleus. The mean epsp rise times were 1.9 ms for electrical stimulation and 6.6 ms for tendon percussion. There was evidence that the duration of the electrically evoked epsp was curtailed by an inhibitory post-synaptic potential (ipsp) of only slightly longer latency than the epsp. The mechanically induced and electrically induced afferent volleys are not homogeneous volleys in group Ia afferents from triceps surae. The afferent volleys differ in so many respects that it is probably invalid to compare the H reflex and tendon jerk as a measure of fusimotor activity. Neither reflex can be considered a purely monosynaptic reflex.