IRCCS Neuromed, Pozzilli (IS), Italy "Sapienza" University of Rome, Department of Medicosurgical Sciences and Biotechnologies, Neurology Section, Rome, Italy "Sapienza" University of Rome, Department of Medicosurgical Sciences and Biotechnologies, Latina, Italy G.B. Bietti Foundation-IRCCS, Department of Neurophysiology of Vision and Neurophthalmology, Rome, Italy.
Pain. 2013 Sep;154(9):1738-1742. doi: 10.1016/j.pain.2013.05.023. Epub 2013 May 18.
The period between migraine attacks is characterized by paradoxical responses to repetitive sensory and transcranial magnetic stimulation (TMS). Abnormal long-term cortical functional plasticity may play a role and can be assessed experimentally by paired associative stimulation (PAS), in which somatosensory peripheral nerve stimuli are followed by TMS of the motor cortex. Changes in motor-evoked potential (MEP) amplitudes were recorded in 16 migraine without aura patients (MO) and 15 healthy volunteers (HV) before and after PAS, which consisted of 90 peripheral electrical right ulnar nerve stimulations and subsequent TMS pulses over the first dorsal interosseous (FDI) muscle activation site with a delay of 10 ms (excitability depressing) or 25 ms (excitability enhancing). As a control experiment of the 31 subjects studied, 8 (4 MO and 4 HV) also underwent PAS10 earlier, the recording of somatosensory high-frequency oscillations (HFOs) reflecting thalamocortical activation (early HFOs). Although PAS10 reduced MEP amplitudes in HV (-17.7%), it significantly increased amplitudes in MO (+35.9%). Although in HV MEP amplitudes were significantly potentiated (+55.1) after PAS25, only a slight, nonsignificant increase was observed in MO (+18.8%). In the control experiment, performed on 8 subjects pooled together, Pearson's correlation showed an inverse relationship between the percentage of MEP amplitude changes after PAS10 and early HFO amplitudes (r=-0.81; P=.01). Because we observed that the more deficient the long-term PAS-induced change, the more the thalamocortical activation decreased, we hypothesize that the abnormalities in long-term cortical plasticity observed in the interictal period between migraine episodes could be due to altered thalamic control.
偏头痛发作间期的特点是对重复感觉和经颅磁刺激（TMS）的矛盾反应。异常的皮质长期功能可塑性可能起作用，可以通过配对关联刺激（PAS）进行实验评估，其中躯体感觉外周神经刺激后，对运动皮层进行 TMS。在偏头痛无先兆患者（MO）16 例和健康志愿者（HV）15 例中，在 PAS 前后记录运动诱发电位（MEP）幅度的变化，PAS 由 90 次右侧尺神经外周电刺激和随后的 TMS 脉冲组成，刺激第一背间骨间肌激活部位，延迟 10ms（兴奋性降低）或 25ms（兴奋性增强）。作为研究的 31 名受试者的对照实验，8 名（4 名 MO 和 4 名 HV）也更早地进行了 PAS10，记录了反映丘脑皮质激活的体感高频振荡（HFOs）（早期 HFOs）。尽管 PAS10 降低了 HV 的 MEP 幅度（-17.7%），但它显著增加了 MO 的 MEP 幅度（+35.9%）。尽管 HV 中的 MEP 幅度在 PAS25 后显著增强（+55.1%），但 MO 中仅观察到轻微的、无统计学意义的增加（+18.8%）。在对照组实验中，对 8 名受试者进行了汇总分析，Pearson 相关性显示 PAS10 后 MEP 幅度变化的百分比与早期 HFO 幅度之间存在反比关系（r=-0.81；P=.01）。因为我们观察到，长期 PAS 诱导的变化越不足，丘脑皮质激活就越少，所以我们假设在偏头痛发作间期的间歇期观察到的皮质长期可塑性异常可能是由于丘脑控制的改变所致。
