Descending spinal cord volleys evoked by transcranial magnetic and electrical stimulation of the motor cortex leg area in conscious humans
Descending spinal cord volleys evoked by transcranial magnetic and electrical stimulation of the motor cortex leg area in conscious humans
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DOI：
10.1113/jphysiol.2001.012572
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发表时间：
2001-12-15
影响因子：
5.5
通讯作者：
Rothwell, JC
中科院分区：
文献类型：
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作者：
Di Lazzaro, V;Oliviero, A;Rothwell, JC
1.经颅磁刺激或电刺激运动皮层腿部区域后，从6名植入电极治疗慢性疼痛的清醒患者和1名接受脊髓肿瘤手术的麻醉患者的脊髓硬膜外腔中的电极记录了下行皮质脊髓齐射。在阈值，最短的潜伏期凌空（L1凌空）诱发的刺激与阳极2厘米侧的顶点。在两名患者中，在顶点处的阳极刺激也在此潜伏期引起齐射，但在其他患者中，第一次齐射诱发出现在1-1.3 ms后（L2齐射），与磁刺激诱发的初始齐射的潜伏期相同。任何类型的高强度刺激都可以引起L1和L2波以及后来的L3，L4等。其具有大约1.5毫秒的周期性。随意收缩使L2及以后截击的幅度增大，但对L1截击没有影响.磁刺激对之间的皮质内抑制导致L4和以后的波的明显抑制。L2、L3波不受影响.在麻醉患者中，L1排波发生的时间比脑干皮质脊髓通路经乳突刺激产生的排波晚1.7 ms。L1的齐射很可能是由皮质下白色物质中的锥体轴突的直接激活产生的D波; L2和以后的齐射很可能是由皮质脊髓神经元的跨突触激活产生的I波。这意味着，在顶点处使用阳极的电刺激比在手部区域上的刺激更可能优先诱发I波。确保D波激活腿部皮质脊髓纤维的更安全的方法是将阳极放置在顶点外侧2 cm处。
1. Descending corticospinal volleys evoked after transcranial magnetic or electrical stimulation of the leg area of the motor cortex were recorded from an electrode in the spinal epidural space of six conscious patients who had electrodes implanted for treatment of chronic pain, and from one anaesthetised patient undergoing surgery for a spinal tumour.2. At threshold, the shortest-latency volley (L1 volley) was evoked by stimulation with an anode 2 cm lateral to the vertex. Anodal stimulation at the vertex also elicited a volley at this latency in two patients, but in the other patients the first volley evoked appeared 1-1.3 ms later (L2 volley), at the same latency as the initial volley evoked by magnetic stimulation. High-intensity stimulation of any type, could evoke both the L1 and L2 waves as well as later ones (L3, L4, etc.) that had a periodicity of about 1.5 ms.3. Voluntary contraction increased the amplitude of the L2 and later volleys, but had no effect on the L1 volley.4. Intracortical inhibition between pairs of magnetic stimuli resulted in clear suppression of the L4 and later waves. The L2 and L3 waves were unaffected.5. In the anaesthetised patient the L1 volley occurred 1.7 ms later than the volley produced by transmastoid stimulation of the corticospinal pathways in the brainstem.6. The L1 volley is likely to be a D wave produced by the direct activation of pyramidal axons in the subcortical white matter; the L2 and later volleys are likely to be I waves produced by the trans-synaptic activation of corticospinal neurones, The implication is that electrical stimulation with an anode at the vertex is more likely to evoke I waves preferentially than stimulation over the hand area. A more secure way to ensure D wave activation of corticospinal fibres from the leg area is to place the anode 2 cm lateral to the vertex.