Abstract:
Brain dynamics is highly non-stationary, permanently subject to ever-changing external conditions and continuously monitoring and adjusting internal control mechanisms. Finding stationary structures in this system, as has been done recently, is therefore of great importance for understanding fundamental dynamic trade relationships. Here we analyse electroencephalographic recordings (EEG) of 13 subjects with unresponsive wakefulness syndrome (UWS) during rest and while being influenced by different acoustic stimuli. We compare the results with a control group under the same experimental conditions and with clinically healthy subjects during overnight sleep. The main objective of this study is to investigate whether a stationary correlation pattern is also present in the UWS group, and if so, to what extent this structure resembles the one found in healthy subjects. Furthermore, we extract transient dynamical features via specific deviations from the stationary interrelation pattern. We find that (i) the UWS group is more heterogeneous than the two groups of healthy subjects, (ii) also the EEGs of the UWS group contain a stationary cross-correlation pattern, although it is less pronounced and shows less similarity to that found for healthy subjects and (iii) deviations from the stationary pattern are notably larger for the UWS than for the two groups of healthy subjects. The results suggest that the nervous system of subjects with UWS receive external stimuli but show an overreaching reaction to them, which may disturb opportune information processing.
摘要:
大脑动力学是高度不稳定的,永久受制于不断变化的外部条件,并持续监控和调整内部控制机制。在这个系统中找到固定结构,正如最近所做的那样,因此,对于理解基本的动态贸易关系非常重要。在这里,我们分析了13位在休息期间和受不同声刺激影响的无反应觉醒综合征(UWS)受试者的脑电图记录(EEG)。我们将结果与相同实验条件下的对照组以及过夜睡眠期间的临床健康受试者进行比较。这项研究的主要目的是调查在UWS组中是否也存在平稳相关模式,如果是这样,这种结构在多大程度上类似于健康受试者中的结构。此外,我们通过与平稳相互关系模式的特定偏差提取瞬态动力学特征。我们发现(I)UWS组比两组健康受试者更异质,(Ii)UWS组的EEG也包含平稳的互相关模式,尽管它不太明显,并且与健康受试者的相似性较小,并且(iii)UWS与固定模式的偏差明显大于两组健康受试者。结果表明,患有UWS的受试者的神经系统接受外部刺激,但对它们表现出过度的反应,这可能会干扰适当的信息处理。