Institute of Neural Engineering, Graz University of Technology, Graz, Austria; BioTechMed Graz, Graz, Austria.
Institute of Psychology, University of Graz, Graz, Austria; BioTechMed Graz, Graz, Austria.
Clin Neurophysiol. 2021 Sep;132(9):2083-2090. doi: 10.1016/j.clinph.2021.05.021. Epub 2021 Jun 18.
Although about 1-2% of MRI examinations must be aborted due to anxiety, there is little research on how MRI-related anxiety affects BOLD signals in resting states.
We re-analyzed cardiac beat-to beat interval (RRI) and BOLD signals of 23 healthy fMRI participants in four resting states by calculation of phase-coupling in the 0.07-0.13 Hz band and determination of positive time delays (pTDs; RRI leading neural BOLD oscillations) and negative time delays (nTDs; RRI lagging behind vascular BOLD oscillations). State anxiety of each subject was assigned to either a low anxiety (LA) or a high anxiety (HA, with most participants exhibiting moderate anxiety symptoms) category based on the inside scanner assessed anxiety score.
Although anxiety strongly differed between HA and LA categories, no significant difference was found for nTDs. In contrast, pTDs indicating neural BOLD oscillations exhibited a significant cumulation in the high anxiety category.
Findings may suggest that vascular BOLD oscillations related to slow cerebral blood circulation are of about similar intensity during low/no and elevated anxiety. In contrast, neural BOLD oscillations, which might be associated with a central rhythm generating mechanism (pacemaker-like activity), appear to be significantly intensified during elevated anxiety.
The study provides evidence that fMRI-related anxiety can activate a central rhythm generating mechanism very likely located in the brain stem, associated with slow neural BOLD oscillation.
尽管约有 1-2%的 MRI 检查因焦虑而必须中止，但对于 MRI 相关焦虑如何影响静息状态下的 BOLD 信号，研究甚少。
我们通过计算 0.07-0.13 Hz 频段的相位耦合，并确定正时间延迟（RRI 领先于神经 BOLD 振荡的 pTDs）和负时间延迟（RRI 落后于血管 BOLD 振荡的 nTDs），重新分析了 23 名健康 fMRI 参与者在四个静息状态下的心动周期（RRI）和 BOLD 信号。根据扫描室内评估的焦虑评分，将每个被试的状态焦虑分为低焦虑（LA）或高焦虑（HA，大多数参与者表现出中度焦虑症状）类别。
尽管 HA 和 LA 类别之间的焦虑差异很大，但 nTDs 没有发现显著差异。相比之下，表明神经 BOLD 振荡的 pTDs 在高焦虑类别中表现出明显的累积。
研究结果可能表明，与缓慢脑血流相关的血管 BOLD 振荡在低/无焦虑和焦虑升高期间的强度大致相同。相比之下，与中央节律生成机制（类似起搏器的活动）相关的神经 BOLD 振荡在焦虑升高期间似乎明显增强。
该研究提供了证据表明，与 fMRI 相关的焦虑可能会激活非常可能位于脑干中的中央节律生成机制，与缓慢的神经 BOLD 振荡相关。
