TASK-RELATED CHANGES IN THE EFFECT OF MAGNETIC BRAIN-STIMULATION ON SPINAL NEURONS IN MAN
TASK-RELATED CHANGES IN THE EFFECT OF MAGNETIC BRAIN-STIMULATION ON SPINAL NEURONS IN MAN
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DOI：
10.1113/jphysiol.1993.sp019899
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发表时间：
1993-11-01
影响因子：
5.5
通讯作者：
BALLEGAARD, M
中科院分区：
文献类型：
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作者：
NIELSEN, J;PETERSEN, N;BALLEGAARD, M
1.采用H反射测试，研究磁刺激人体运动皮层对比目鱼肌、胫前肌和桡侧腕屈肌运动神经元兴奋性的影响.在休息时，桡侧腕屈肌和胫前肌H反射的早期促进总是看到，而类似的早期促进比目鱼肌H反射中看到只有两个7个科目。对于所有三个运动神经元池，1-5 ms后，抑制持续3-4 ms，促进被削减。在5个受试者中，比目鱼肌H反射的抑制没有任何早期促进的证据。随后降低磁刺激的强度，使其对静止时的H反射没有影响。然后，当受试者进行自主激动剂收缩时，观察到所有三块肌肉的早期发作和持续时间为20-25 ms的易化效应。当受试者进行自主拮抗收缩时，比目鱼肌H反射出现抑制，其起始时间比易化时间晚1-3 ms。这被解释为皮质脊髓神经元的磁刺激兴奋与给定的运动任务有关的自愿激活。在激动剂和拮抗剂共同收缩时，易化的初始部分明显小于单独激动剂收缩时。虽然促进的早期部分总是发生在跖屈时，H反射的条件是由磁刺激，这是从来没有的情况下，当它是由电刺激的皮层与这些实验中使用的刺激制度。这表明，在激动剂收缩过程中观察到的便利化的早期部分是由激活的皮质运动神经元细胞投射到激动剂运动神经元池和拮抗剂收缩过程中观察到的抑制是由激活的皮质脊髓细胞投射到拮抗剂运动神经元池和抑制性中间神经元的激动剂运动神经元池。较小的尺寸的最早期的一部分，在共同收缩的激动剂收缩期间观察到的促进表明不同的皮质控制的两个任务。
1. The effect of magnetic stimulation of the human motor cortex on the excitability of soleus, tibialis anterior and flexor carpi radialis motoneurones was investigated by H reflex testing in ten healthy subjects.2. At rest, an early facilitation of the flexor carpi radialis and tibialis anterior H reflexes was always seen, whereas a similar early facilitation of the soleus H reflex was seen in only two out of seven subjects. For all three motoneuronal pools the facilitation was curtailed 1-5 ms later by an inhibition which lasted for another 3-4 ms. In five subjects an inhibition without any evidence of an earlier facilitation was seen for the soleus H reflex.3. The intensity of the magnetic stimulation was subsequently decreased so that it had no effect on the H reflex at rest. When the subject then performed a voluntary agonist contraction a facilitatory effect with an early onset and a duration of 20-25 ms was observed for all three muscles. When the subject performed a voluntary antagonist contraction an inhibition was seen for the soleus H reflex with an onset 1-3 ms later than the facilitation. This is interpreted as resulting from the excitation by the magnetic stimulus of corticospinal neurones voluntarily activated in relation to the given motor task.4. The initial part of the facilitation was significantly smaller during co-contraction of both agonists and antagonists than during isolated agonist contraction.5. Whereas the early part of the facilitation always occurred during plantarflexion when the H reflex was conditioned by magnetic stimulation, this was never the case when it was conditioned by electrical stimulation of the cortex with the stimulus regimes used in these experiments.6. It is suggested that the early part of the facilitation observed during agonist contraction is caused by activation of corticomotoneuronal cells projecting to the agonist motoneuronal pool and that the inhibition observed during antagonist contraction is caused by activation of corticospinal cells projecting both to the antagonist motoneuronal pool and la inhibitory interneurones to the agonist motoneuronal pool. The smaller size of the earliest part of the facilitation observed during co-contraction in relation to agonist contraction suggests a different cortical control of the two tasks.