Coppola G, Pierelli F, Schoenen J
G.B. Bietti Eye Foundation-IRCCS, Department of Neurophysiology of Vision and Neurophthalmology, Rome, Italy.
Cephalalgia. 2007 Dec;27(12):1427-39. doi: 10.1111/j.1468-2982.2007.01500.x.
Although migraineurs appear in general to be hypersensitive to external stimuli, they maybe also have increased daytime sleepiness and complain of fatigue. Neurophysiological studies between attacks have shown that for a number of different sensory modalities the migrainous brain is characterised by a lack of habituation of evoked responses. Whether this is due to increased cortical hyperexcitability, possibly due to decreased inhibition, or to an abnormal responsivity of the cortex due a decreased preactivation level remains disputed. Studies using transcranial magnetic stimulation in particular have yielded contradictory results. We will review here the available data on cortical excitability obtained with different methodological approaches in patients over the migraine cycle. We will show that these data congruently indicate that the sensory cortices of migraineurs react excessively to repetitive, but not to single, stimuli and that the controversy above hyper- versus hypo-excitability is merely a semantic misunderstanding. Describing the migrainous brain as 'hyperresponsive' would fit most of the available data. Deciphering the precise cellular and molecular underpinnings of this hyperresponsivity remains a challenge for future research. We propose, as a working hypothesis, that a thalamo-cortical dysrhythmia might be the culprit.
尽管偏头痛患者总体上似乎对外界刺激过敏，但他们白天也可能更容易困倦并抱怨疲劳。发作间期的神经生理学研究表明，对于多种不同的感觉模态，偏头痛患者的大脑表现为诱发反应缺乏习惯化。这是由于皮质兴奋性增加（可能是由于抑制作用降低），还是由于预激活水平降低导致皮质反应异常，仍存在争议。特别是使用经颅磁刺激的研究得出了相互矛盾的结果。我们将在此回顾在偏头痛发作周期中，通过不同方法获得的关于患者皮质兴奋性的现有数据。我们将表明，这些数据一致表明，偏头痛患者的感觉皮层对重复性刺激反应过度，但对单次刺激无过度反应，而且上述关于兴奋性过高与过低的争议仅仅是语义上的误解。将偏头痛患者的大脑描述为“反应过度”符合大多数现有数据。解读这种反应过度的确切细胞和分子基础仍是未来研究的一项挑战。作为一个可行的假设，我们提出丘脑 - 皮质节律失调可能是罪魁祸首。
