Effect of coil orientation on strength-duration time constant and I-wave activation with controllable pulse parameter transcranial magnetic stimulation.
Effect of coil orientation on strength-duration time constant and I-wave activation with controllable pulse parameter transcranial magnetic stimulation.
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线圈方向对强度持续时间常数和I波激活的影响，具有可控的脉冲参数经颅磁刺激。
DOI：
10.1016/j.clinph.2015.05.017
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发表时间：
2016-01
期刊：
影响因子：
--
通讯作者：
Rothwell JC
中科院分区：
文献类型：
--
作者：
D'Ostilio K;Goetz SM;Hannah R;Ciocca M;Chieffo R;Chen JA;Peterchev AV;Rothwell JC
前-后感应电流的S-D时间常数比后-前感应电流的S-D时间常数长。短暂（30 μs）的前后电流诱发最长潜伏期的MEP。神经元件的选择性刺激可以通过操纵脉冲宽度和方向来实现。比较跨中央沟的电流脉冲定向后-前（PA）或前-后（AP）激活的运动皮质结构的强度-持续时间（S-D）时间常数。采用可控脉冲参数（cTMS）装置，线圈指向PA或AP，在30、60和120 μs的脉冲宽度下测定第一骨间背侧肌的运动阈值、输入输出曲线和运动诱发电位（MEP）潜伏期。这些被用来估计的S-D时间常数，我们比较了手肘尺神经的cTMS诱发的反应的数据。PA刺激的S-D时间常数短于AP刺激（230.9 ± 97.2 vs. 294.2 ± 90.9 μs; p < 0.001）。这些值与刺激尺神经后计算的值（197 ± 47 μs）相似。MEP对AP的潜伏期受脉冲宽度的影响，而对PA的刺激则不受影响，短时间刺激后潜伏期延长。PA和AP刺激似乎以不同的时间常数激活神经元的轴突。短持续时间的AP脉冲比长脉冲在招募较长潜伏期的皮质脊髓输出方面更具选择性。可以通过操纵脉冲宽度和方向来实现对神经元件的更有选择性的刺激。
S–D time constants are longer for anterior–posterior than posterior–anterior induced currents. Brief (30 μs) anterior-posterior currents evoke the longest latency MEP. Selective stimulation of neural elements may be achieved by manipulating pulse width and orientation. To compare the strength–duration (S–D) time constants of motor cortex structures activated by current pulses oriented posterior–anterior (PA) or anterior–posterior (AP) across the central sulcus. Motor threshold and input–output curve, along with motor evoked potential (MEP) latencies, of first dorsal interosseus were determined at pulse widths of 30, 60, and 120 μs using a controllable pulse parameter (cTMS) device, with the coil oriented PA or AP. These were used to estimate the S–D time constant and we compared with data for responses evoked by cTMS of the ulnar nerve at the elbow. The S–D time constant with PA was shorter than for AP stimulation (230.9 ± 97.2 vs. 294.2 ± 90.9 μs; p < 0.001). These values were similar to those calculated after stimulation of ulnar nerve (197 ± 47 μs). MEP latencies to AP, but not PA stimulation were affected by pulse width, showing longer latencies following short duration stimuli. PA and AP stimuli appear to activate the axons of neurons with different time constants. Short duration AP pulses are more selective than longer pulses in recruiting longer latency corticospinal output. More selective stimulation of neural elements may be achieved by manipulating pulse width and orientation.