Using EEG to Explore How rTMS Produces Its Effects on Behavior
Using EEG to Explore How rTMS Produces Its Effects on Behavior
复制标题
DOI：
10.1007/s10548-009-0118-1
复制
发表时间：
2010-01-01
期刊：
影响因子：
2.7
通讯作者：
Postle, Bradley R.
中科院分区：
文献类型：
--
作者：
Johnson, Jeffrey S.;Hamidi, Massihullah;Postle, Bradley R.
人们普遍认为，在执行任务期间，重复性 TMS (rTMS) 通过在目标组织中产生短暂的“虚拟损伤”来影响行为。然而，与 rTMS 相关的性能改善的发现很难与这一假设相一致。关于 rTMS 影响并发任务表现的机制，我们实验室进行的一项 rTMS/EEG 联合研究揭示了 rTMS、EEG 活动和行为表现之间的一组复杂关系，rTMS 对 α 波段功率和 α:gamma 相位同步的影响均预测其对行为的影响。这些发现表明，rTMS 通过偏置与任务相关的内源振荡动力学来影响表现，而不是产生“虚拟损伤”。为了进一步区分这两种替代方案，在本研究中，我们将 10 Hz rTMS 对神经活动的影响与用 10 Hz 亮度闪烁代替 rTMS 的实验结果进行了比较。我们推断 10 Hz 闪烁会产生广泛的神经活动夹带到闪烁频率，并且将这些脑电图结果与 rTMS 研究的结果进行比较将揭示后者是否也反映了外源刺激的夹带。结果揭示了 10 Hz 闪烁产生的“夹带噪声”的明显证据——增加了驱动频率下的振荡功率和试验间相干性 (ITC)，并增加了 alpha:gamma 相位同步——尽管如此，这些噪声在很大程度上与行为无关。这与 10 Hz rTMS 形成鲜明对比，对于 10 Hz rTMS，刺激引起的噪声的唯一证据是 30 Hz 时 ITC 升高，与闪烁结果有质的不同。因此，同步记录脑电图提供了一种直接测试 rTMS 如何对行为产生影响的假设的重要手段。
A commonly held view is that, when delivered during the performance of a task, repetitive TMS (rTMS) influences behavior by producing transient "virtual lesions" in targeted tissue. However, findings of rTMS-related improvements in performance are difficult to reconcile with this assumption. With regard to the mechanism whereby rTMS influences concurrent task performance, a combined rTMS/EEG study conducted in our lab has revealed a complex set of relations between rTMS, EEG activity, and behavioral performance, with the effects of rTMS on power in the alpha band and on alpha:gamma phase synchrony each predicting its effect on behavior. These findings suggest that rTMS influences performance by biasing endogenous task-related oscillatory dynamics, rather than creating a "virtual lesion". To further differentiate these two alternatives, in the present study we compared the effects of 10 Hz rTMS on neural activity with the results of an experiment in which rTMS was replaced with 10 Hz luminance flicker. We reasoned that 10 Hz flicker would produce widespread entrainment of neural activity to the flicker frequency, and comparison of these EEG results with those from the rTMS study would shed light on whether the latter also reflected entrainment to an exogenous stimulus. Results revealed pronounced evidence for "entrainment noise" produced by 10 Hz flicker-increased oscillatory power and inter-trial coherence (ITC) at the driving frequency, and increased alpha:gamma phase synchronization-that were nonetheless largely uncorrelated with behavior. This contrasts markedly with 10-Hz rTMS, for which the only evidence for stimulation-induced noise, elevated ITC at 30 Hz, differed qualitatively from the flicker results. Simultaneous recording of the EEG thus offers an important means of directly testing assumptions about how rTMS exerts its effects on behavior.