The effect of current direction induced by transcranial magnetic stimulation on the corticospinal excitability in human brain
The effect of current direction induced by transcranial magnetic stimulation on the corticospinal excitability in human brain
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DOI：
10.1016/s0921-884x(96)96021-x
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发表时间：
1996-12-01
期刊：
影响因子：
--
通讯作者：
Ofuji, A
中科院分区：
文献类型：
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作者：
Kaneko, K;Kawai, S;Ofuji, A
在6名受试者中，采用两种不同的线圈方位经颅磁刺激运动皮层，同时记录颈部硬膜外腔的脊髓诱发电位（ESCPs）和手部肌肉的运动诱发电位（MEP）。当感应电流在运动皮层上沿侧-中方向（L-M刺激）流动时，MEP的起始潜伏期比沿后-前方向（P-A刺激）流动时短约1 ms。因此，L-M刺激引起的ESCPs比P-A刺激诱导的更早的成分。在七氟烷全身麻醉期间，L-M刺激后仅可常规诱发ESCP的第一组分。与此相反，所有成分的ESCP显着衰减后P-A刺激。此外，L-M刺激诱发的ESCP的第一成分潜伏期与经颅阳极电刺激诱发的ESCP的第一成分潜伏期基本相同。这些结果表明，如果经颅磁刺激后的感应电流在运动皮层上沿侧内侧方向流动，则其优先刺激皮质脊髓束非突触（产生D波）。然而，如果感应电流表现为后-前方向，则优先跨突触刺激皮质脊髓束（产生I波）。因此，磁感应电流的方向在确定人脑皮质脊髓兴奋性方面至关重要。版权所有（C）1996 Elsevier Science爱尔兰有限公司
Evoked spinal cord potentials (ESCPs) from the cervical epidural space and motor evoked potentials (MEPs) from the hand muscles were recorded simultaneously in 6 subjects following transcranial magnetic stimulation in two different coil orientations on motor cortex. The onset latency of the MEPs was approximately 1 ms shorter when the induced current flowed in a latero-medial direction (L-M stimulation) on the motor cortex as compared to a postero-anterior direction (P-A stimulation). Hence, L-M stimulation elicited an earlier component of the ESCPs than that induced by P-A stimulation. During general anesthesia with Sevoflurane, only the first component of the ESCPs could be elicited routinely following L-M stimulation. In contrast, all components of the ESCPs were dramatically attenuated following P-A stimulation. Moreover, first component latency of the ESCPs induced by L-M stimulation was almost the same as that induced by transcranial anodal electrical stimulation. These results suggest that if the induced current following transcranial magnetic stimulation flows in a latero-medial direction on motor cortex, it preferentially stimulates the corticospinal tract non-synaptically (producing a D-wave). However, if the induced current hows in a postero-anterior direction, it preferentially stimulates the corticospinal tract trans-synaptically (producing I-waves). Therefore, the direction of magnetically induced current is crucial in determining corticospinal excitability in the human brain. Copyright (C) 1996 Elsevier Science Ireland Ltd.