Translational Research Center, University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland.
Brain Topogr. 2023 Jan;36(1):32-41. doi: 10.1007/s10548-022-00933-w. Epub 2022 Dec 19.
Our knowledge about the human resting state is predominantly based on either electroencephalographic (EEG) or functional magnetic resonance imaging (fMRI) methods. While EEG recordings can be performed in seated posture in quiet conditions, the fMRI environment presents a substantial contrast with supine and restricted posture in a narrow tube that is filled with acoustic scanner noise (ASN) at a chainsaw-like volume level. However, the influence of these diverging conditions on resting-state brain activation is neither well studied nor broadly discussed. In order to promote data as a source of sharper hypotheses for future studies, we investigated alterations in EEG-frequency-band power (delta, theta, alpha, beta, gamma) and spatial power distribution as well as cortical vigilance measures in different postures and ASN surroundings over the course of time. Participants (N = 18) underwent three consecutive resting-state EEG recordings with a fixed posture and ASN setting sequence; seated, supine, and supine with ASN (supnoise) using an MRI simulator. The results showed that compared to seated, supnoise, the last instance within the posture sequence, was characterized by lower power and altered spatial power distribution in all assessed frequency bands. This might also have been an effect of time alone. In delta, theta, alpha, and beta, the power of supnoise was also reduced compared to supine, as well as the corresponding distribution maps. The vigilance analysis revealed that in supine and supnoise, the highest and lowest vigilance stages were more dominant compared to the seated and earliest posture condition within the sequence. Hence, our results demonstrate that the differences in recording settings and progress of time are related to changes in cortical arousal and vigilance regulation, findings that should be taken into account more profoundly for hypothesis generation as well as analytic strategies in future resting-state studies.
我们对人类静息状态的了解主要基于脑电图 (EEG) 或功能磁共振成像 (fMRI) 方法。虽然 EEG 记录可以在安静的坐姿下进行，但 fMRI 环境与仰卧位和限制在充满声学扫描仪噪声 (ASN) 的狭窄管内的姿势形成了巨大的对比，而 ASN 的音量水平如链锯一般。然而，这些不同条件对静息态大脑激活的影响既没有得到很好的研究，也没有得到广泛的讨论。为了促进数据成为未来研究更尖锐假设的来源，我们研究了在不同姿势和 ASN 环境下，随时间推移 EEG 频带功率（δ、θ、α、β、γ）和空间功率分布以及皮质警觉性测量的变化。参与者（N=18）连续进行了三次静息状态 EEG 记录，采用固定姿势和 ASN 设置序列；坐姿、仰卧位和仰卧位加 ASN（supnoise），使用 MRI 模拟器。结果表明，与坐姿相比，在姿势序列的最后一个位置 supnoise 特征是所有评估频带的功率降低和空间功率分布改变。这也可能仅仅是时间的影响。在δ、θ、α 和β 中，supnoise 的功率也比 supnoise 降低，相应的分布图也是如此。警觉性分析表明，在仰卧位和 supnoise 中，最高和最低警觉阶段比序列中的坐姿和最早姿势条件更为突出。因此，我们的结果表明，记录设置和时间进展的差异与皮质唤醒和警觉调节的变化有关，这些发现应该在未来的静息态研究中更深入地考虑，以便生成假设和分析策略。
