The neural response to transcranial magnetic stimulation of the human motor cortex. I. Intracortical and cortico-cortical contributions
The neural response to transcranial magnetic stimulation of the human motor cortex. I. Intracortical and cortico-cortical contributions
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对人类运动皮层经颅磁刺激的神经反应。
DOI：
10.1007/s00221-006-0551-2
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发表时间：
2006
影响因子：
2
通讯作者：
T. Paus
中科院分区：
文献类型：
--
作者：
Y. D. Werf;T. Paus
我们研究了经颅磁刺激（TMS）应用于人类初级运动皮层的神经反应的性质。与我们以前的发现一致，TMS的单脉冲在45 ms（N45）处诱导特征性负偏转，并在β频率范围（15-30 Hz）内诱导瞬时振荡，如使用脑电图（EEG）所测量的。在这里，我们显示的β振荡和N45的相对特异性，两者都是较强的，当引起的刺激施加在初级运动皮层，相比，在背侧运动前皮层的刺激。我们还提供了一个定量分析的β响应TMS的单脉冲，并表明，响应是高度锁相的TMS脉冲在单一的主题，这种锁相是类似的主题。因此，在初级运动皮层上施加一个单一的TMS脉冲似乎可以重置神经元的持续振荡，使它们暂时同步。最后，我们研究的影响，本地或远端调制的兴奋性的初级运动皮层的β振荡和N45在响应于单脉冲TMS。我们应用低频阈下重复TMS无论是在初级运动皮层（局部调制），或在一个单独的一天，在背侧前运动皮层（远端调制）。在阈下低频rTMS之前和之后，在初级运动皮层上施加TMS的单个阈上测试脉冲来评价调制。我们记录了整个测试过程中的EEG响应，即对阈下和阈上脉冲的响应。在初级运动皮层（而不是背侧运动前皮层）上重复TMS后，响应阈上脉冲的N45的振幅倾向于降低（不显著），随后增加（显著）;两种类型的重复TMS都不影响β振荡的振幅。我们的结论是：（1）N45依赖于初级运动皮层固有的电路;（2）β振荡是特定于初级运动皮层的刺激，但不受任何皮层区域的调制;（3）对TMS脉冲的β振荡反应来自于正在进行的振荡的重置，而不是它们的诱导。
We investigated the properties of the neural response to transcranial magnetic stimulation (TMS) applied over the human primary motor cortex. Consistent with our previous findings, single pulses of TMS induce a characteristic negative deflection at 45 ms (N45) and a transient oscillation in the beta frequency-range (15–30 Hz), as measured using electroencephalograpy (EEG). Here we show the relative specificity of the beta oscillation and the N45; both are stronger when elicited by stimulation applied over the primary motor cortex, as compared with stimulation over the dorsal premotor cortex. We also provide a quantitative analysis of the beta responses to single pulses of TMS and show that the responses are highly phaselocked to the TMS pulses within single subjects; this phaselocking is similar from subject to subject. A single pulse of TMS applied over the primary motor cortex thus appears to reset the ongoing oscillations of the neurons, bringing them transiently into synchrony. Finally, we examine the effect of local or distal modulation of the excitability of the primary motor cortex on the beta oscillation and the N45 in response to single-pulse TMS. We applied low-frequency subthreshold repetitive TMS either over the primary motor cortex (local modulation) or, on a separate day, over the dorsal premotor cortex (distal modulation). The modulation was evaluated with single suprathreshold test pulses of TMS applied over the primary motor cortex before and after the subthreshold low-frequency rTMS. We recorded the EEG response throughout the testing session, i.e. to both the subthreshold and the suprathreshold pulses. After repetitive TMS applied over the primary motor cortex, but not the dorsal premotor cortex, the amplitude of the N45 in response to suprathreshold pulses tended to decrease (not significant), and subsequently increased (significant); neither type of repetitive TMS affected the amplitude of the beta oscillation. We conclude that (1) the N45 depends on circuits intrinsic to the primary motor cortex; (2) the beta oscillation is specific to stimulation of the primary motor cortex, but is not affected by modulation of either cortical area and; (3) the beta oscillatory response to pulses of TMS arises from resetting of ongoing oscillations rather than their induction.