Leandri M, Gottlieb A, Cruccu G
Interuniversity Centre for Pain Neurophysiology and Department of Oncology, Biology and Genetics at the University of Genova, Via Dodecaneso 35, 16146, Genova, Italy.
Clin Neurophysiol. 2001 Oct;112(10):1828-32. doi: 10.1016/s1388-2457(01)00648-4.
Excitatory and inhibitory responses have been recognized in human cervical muscles following trigeminal stimulation. However, no evidence has so far been published of a crossed, short-latency, excitatory response resembling the early head extensor reflex seen in the cat. We seek its existence in humans.
The study was carried out in 14 voluntary healthy subjects. Percutaneous and surface electrical stimulation of the supraorbital and infraorbital nerves was performed with single, double and repetitive stimuli. Signals were recorded from the relaxed splenius and sternomastoid muscles bilaterally.
Percutaneous stimulation of infraorbital nerve with single stimuli evoked an early response in the contralateral splenius muscle, with onset latency ranging from 11 to 14 ms (HR1). This response was greatly facilitated by double or repetitive stimuli. Single stimuli also gave rise to two larger responses in all 4 muscles in the latency ranges 50-70 ms (HR2) and 100-160 ms (HR3). Surface stimulation of one nerve alone could not elicit any early activity. Single surface stimuli delivered simultaneously to the supraorbital and infraorbital nerves evoked HR1 in only 5 subjects.
We detected a crossed early reflex of the head extensor muscles to trigeminal stimuli. Its timing is similar to the 8-ms response seen in cats. The evidence provided suggests that the reflex is mediated by an oligosynaptic circuit and that it needs a strong spatial summation at central synapses.
三叉神经刺激后，人类颈部肌肉可出现兴奋性和抑制性反应。然而，目前尚未有文献报道存在类似于猫早期头部伸肌反射的交叉性、短潜伏期兴奋性反应。我们探究其在人类中的存在情况。
对14名健康志愿者进行了研究。采用单刺激、双刺激和重复刺激对眶上神经和眶下神经进行经皮和表面电刺激。双侧记录放松状态下的斜方肌和胸锁乳突肌的信号。
经皮单刺激眶下神经可在对侧斜方肌诱发早期反应，起始潜伏期为11至14毫秒（HR1）。双刺激或重复刺激可显著增强该反应。单刺激还可在所有4块肌肉中潜伏期为50 - 70毫秒（HR2）和100 - 160毫秒（HR3）时引发两个更大的反应。单独对一条神经进行表面刺激无法诱发任何早期活动。同时对眶上神经和眶下神经进行单表面刺激仅在5名受试者中诱发了HR1。
我们检测到头部伸肌对三叉神经刺激的交叉性早期反射。其时间与猫中观察到的8毫秒反应相似。所提供的证据表明该反射由少突触回路介导，且在中枢突触处需要强烈的空间总和。
