De Gennaro Luigi, Marzano Cristina, Veniero Domenica, Moroni Fabio, Fratello Fabiana, Curcio Giuseppe, Ferrara Michele, Ferlazzo Fabio, Novelli Luana, Concetta Pellicciari Maria, Bertini Mario, Rossini Paolo Maria
Department of Psychology, University of Rome La Sapienza, Rome, Italy.
Neuroimage. 2007 Jul 15;36(4):1277-87. doi: 10.1016/j.neuroimage.2007.04.013. Epub 2007 Apr 18.
Changes of cortical and corticospinal excitability as a function of sleep deprivation have been studied, using EEG power maps and several TMS measures in 33 normal subjects before and after a 40-h sleep deprivation (SD). The effects of SD were independently assessed by subjective and EEG measures of sleepiness, the latter being represented in terms of cortical maps for different frequency bands. Short intracortical facilitation (SICF) and inhibition (SICI) were measured by the paired-pulse TMS technique with different inter-stimulus intervals. Besides standardized motor threshold (MT), lower threshold (LT) and upper threshold (UT) were also determined. Subjective sleepiness severely increased as a consequence of SD, paralleled by a drastic decrease of alertness. EEG topography showed large increases in delta and theta activity, mainly evident at fronto-central areas. Standard MTs, as well as LTs and UTs, all increased as a consequence of SD. SICF also showed a significant increase as compared to pre-deprivation values, but only in females. The increase of theta activity was strongly associated in the left frontal and prefrontal cortex to a smaller decrease of corticospinal excitability, expressed by MTs, and a larger increase of intracortical facilitation, expressed by SICF. TMS and EEG measures converge in indicating that SD has severe effects on both cortical and corticospinal excitability, as shown respectively by the increases of slow-frequency EEG power and MTs. The SICF enhancement in females and the results of the combined topographical analysis of EEG and TMS changes are coherent with the hypothesis that cortical TMS-evoked responses are higher as a consequence of a longer wakefulness. However, the lack of an increase in cortical excitability after prolonged wakefulness in males suggests some caution in the generalization of these effects, that deserve further investigation.
利用脑电图功率图和多种经颅磁刺激（TMS）测量方法，对33名正常受试者在40小时睡眠剥夺（SD）前后的皮质及皮质脊髓兴奋性变化进行了研究。通过主观嗜睡程度和脑电图测量对睡眠剥夺的影响进行了独立评估，后者以不同频段的皮质图表示。采用配对脉冲TMS技术，在不同刺激间隔下测量短皮质内易化（SICF）和抑制（SICI）。除了标准化运动阈值（MT）外，还确定了下限阈值（LT）和上限阈值（UT）。睡眠剥夺导致主观嗜睡程度严重增加，同时警觉性急剧下降。脑电图地形图显示δ波和θ波活动大幅增加，主要在前额中央区域明显。由于睡眠剥夺，标准MT以及LT和UT均增加。与剥夺前的值相比，SICF也显著增加，但仅在女性中。θ波活动的增加在左侧额叶和前额叶皮质与皮质脊髓兴奋性较小的降低（以MT表示）以及皮质内易化较大的增加（以SICF表示）密切相关。TMS和脑电图测量结果一致表明，睡眠剥夺对皮质和皮质脊髓兴奋性均有严重影响，分别表现为慢频率脑电图功率和MT的增加。女性中SICF的增强以及脑电图和TMS变化的联合地形分析结果与以下假设一致：由于清醒时间延长，皮质TMS诱发反应更高。然而，男性在长时间清醒后皮质兴奋性未增加，这表明在推广这些效应时应谨慎，值得进一步研究。
