Pfurtscheller Gert, Schwerdtfeger Andreas, Brunner Clemens, Aigner Christoph, Fink David, Brito Joana, Carmo Marciano P, Andrade Alexandre
Institute of Neural Engineering, Graz University of Technology, Graz, Austria.
BioTechMed Graz, Graz, Austria.
PLoS One. 2017 Jan 4;12(1):e0168097. doi: 10.1371/journal.pone.0168097. eCollection 2017.
In the resting state, blood oxygen level-dependent (BOLD) oscillations with a frequency of about 0.1 Hz are conspicuous. Whether their origin is neural or vascular is not yet fully understood. Furthermore, it is not clear whether these BOLD oscillations interact with slow oscillations in heart rate (HR). To address these two questions, we estimated phase-locking (PL) values between precentral gyrus (PCG) and insula in 25 scanner-naïve individuals during rest and stimulus-paced finger movements in both hemispheres. PL was quantified in terms of time delay and duration in the frequency band 0.07 to 0.13 Hz. Results revealed both positive and negative time delays. Positive time delays characterize neural BOLD oscillations leading in the PCG, whereas negative time delays represent vascular BOLD oscillations leading in the insula. About 50% of the participants revealed positive time delays distinctive for neural BOLD oscillations, either with short or long unilateral or bilateral phase-locking episodes. An expected preponderance of neural BOLD oscillations was found in the left hemisphere during right-handed movement and unexpectedly in the right hemisphere during rest. Only neural BOLD oscillations were significantly associated with heart rate variability (HRV) in the 0.1-Hz range in the first resting state. It is well known that participating in magnetic resonance imaging (MRI) studies may be frightening and cause anxiety. In this respect it is important to note that the most significant hemispheric asymmetry (p<0.002) with a right-sided dominance of neural BOLD and a left-sided dominance of vascular BOLD oscillations was found in the first resting session in the scanner-naïve individuals. Whether the enhanced left-sided perfusion (dominance of vascular BOLD) or the right-sided dominance of neural BOLD is related to the increased level of anxiety, attention or stress needs further research.
在静息状态下，频率约为0.1赫兹的血氧水平依赖（BOLD）振荡很明显。其起源是神经源性还是血管源性尚未完全明确。此外，尚不清楚这些BOLD振荡是否与心率（HR）的慢振荡相互作用。为了解决这两个问题，我们在25名未接触过扫描仪的个体静息以及双侧半球进行刺激驱动的手指运动期间，估计了中央前回（PCG）和脑岛之间的锁相（PL）值。PL是根据0.07至0.13赫兹频段内的时间延迟和持续时间来量化的。结果显示了正、负两种时间延迟。正时间延迟表征PCG中领先的神经BOLD振荡，而负时间延迟代表脑岛中领先的血管BOLD振荡。约50%的参与者表现出神经BOLD振荡特有的正时间延迟，存在短期或长期的单侧或双侧锁相事件。在右手运动时，左半球发现神经BOLD振荡占优势，而在静息时右半球出现这种情况则出乎意料。在第一个静息状态下，仅神经BOLD振荡与0.1赫兹范围内的心率变异性（HRV）显著相关。众所周知，参与磁共振成像（MRI）研究可能会令人恐惧并导致焦虑。在这方面，需要注意的是，在未接触过扫描仪的个体的第一次静息扫描中，发现了最显著的半球不对称（p<0.002），即神经BOLD右侧占优势，血管BOLD振荡左侧占优势。增强的左侧灌注（血管BOLD占优势）或神经BOLD右侧占优势是否与焦虑、注意力或压力水平升高有关，需要进一步研究。
