Instituto Israelita de Ensino e Pesquisa, Hospital Israelita Albert Einstein, Av. Albert Einstein, 627/2SS, Morumbi, São Paulo, SP, 05652-900, Brazil.
J Headache Pain. 2012 Jan;13(1):29-37. doi: 10.1007/s10194-011-0379-4. Epub 2011 Sep 1.
Increased, decreased or normal excitability to transcranial magnetic stimulation (TMS) has been reported in the motor (M1) and visual cortices of patients with migraine. Light deprivation (LD) has been reported to modulate M1 excitability in control subjects (CS). Still, effects of LD on M1 excitability compared to exposure to environmental light exposure (EL) had not been previously described in patients with migraine (MP). To further our knowledge about differences between CS and MP, regarding M1 excitability and effects of LD on M1 excitability, we opted for a novel approach by extending measurement conditions. We measured motor thresholds (MTs) to TMS, short-interval intracortical inhibition, and ratios between motor-evoked potential amplitudes and supramaximal M responses in MP and CS on two different days, before and after LD or EL. Motor thresholds significantly increased in MP in LD and EL sessions, and remained stable in CS. There were no significant between-group differences in other measures of TMS. Short-term variation of MTs was greater in MP compared to CS. Fluctuation in excitability over hours or days in MP is an issue that, until now, has been relatively neglected. The results presented here will help to reconcile conflicting observations.
在偏头痛患者的运动（M1）和视觉皮质中，已经报道了经颅磁刺激（TMS）的兴奋性增加、减少或正常。已经报道了光剥夺（LD）可调节对照受试者（CS）中的 M1 兴奋性。然而，在偏头痛患者（MP）中，LD 对 M1 兴奋性的影响与暴露于环境光（EL）相比，以前尚未描述。为了进一步了解 CS 和 MP 之间关于 M1 兴奋性和 LD 对 M1 兴奋性的影响的差异，我们选择了一种新的方法，通过扩展测量条件来进行研究。我们在 LD 或 EL 前后的两天内在 MP 和 CS 上测量了 TMS 的运动阈值（MTs）、短程皮质内抑制以及运动诱发电位幅度与最大 M 反应之间的比值。在 LD 和 EL 期间，MP 的运动阈值显著增加，而 CS 保持稳定。TMS 的其他测量指标在组间没有显著差异。与 CS 相比，MP 中的 MTs 短期变化更大。在数小时或数天内，MP 中的兴奋性波动是一个迄今为止相对被忽视的问题。这里呈现的结果将有助于协调相互矛盾的观察结果。
