Stephenson School of Biomedical Engineering, University of Oklahoma, 110 W. Boyd St. DEH room 150, Norman, OK 73019, USA.
Stephenson School of Biomedical Engineering, University of Oklahoma, 110 W. Boyd St. DEH room 150, Norman, OK 73019, USA; Institute for Biomedical Engineering, Science, and Technology, University of Oklahoma, Norman, USA.
Neuroimage. 2022 Oct 15;260:119460. doi: 10.1016/j.neuroimage.2022.119460. Epub 2022 Jul 19.
Brain-wide patterns in resting human brains, as either structured functional connectivity (FC) or recurring brain states, have been widely studied in the neuroimaging literature. In particular, resting-state FCs estimated over windowed timeframe neuroimaging data from sub-minutes to minutes using correlation or blind source separation techniques have reported many brain-wide patterns of significant behavioral and disease correlates. The present pilot study utilized a novel whole-head cap-based high-density diffuse optical tomography (DOT) technology, together with data-driven analysis methods, to investigate recurring transient brain-wide patterns in spontaneous fluctuations of hemodynamic signals at the resolution of single timeframes from thirteen healthy adults in resting conditions. Our results report that a small number, i.e., six, of brain-wide coactivation patterns (CAPs) describe major spatiotemporal dynamics of spontaneous hemodynamic signals recorded by DOT. These CAPs represent recurring brain states, showing spatial topographies of hemispheric symmetry, and exhibit highly anticorrelated pairs. Moreover, a structured transition pattern among the six brain states is identified, where two CAPs with anterior-posterior spatial patterns are significantly involved in transitions among all brain states. Our results further elucidate two brain states of global positive and negative patterns, indicating transient neuronal coactivations and co-deactivations, respectively, over the entire cortex. We demonstrate that these two brain states are responsible for the generation of a subset of peaks and troughs in global signals (GS), supporting the recent reports on neuronal relevance of hemodynamic GS. Collectively, our results suggest that transient neuronal events (i.e., CAPs), global brain activity, and brain-wide structured transitions co-exist in humans and these phenomena are closely related, which extend the observations of similar neuronal events recently reported in animal hemodynamic data. Future studies on the quantitative relationship among these transient events and their relationships to windowed FCs along with larger sample size are needed to understand their changes with behaviors and diseased conditions.
在神经影像学文献中，广泛研究了静息状态下人类大脑中的全脑模式，包括结构功能连接（FC）或反复出现的大脑状态。特别是，使用相关性或盲源分离技术，从亚分钟到分钟的时间窗口神经影像学数据中估计静息状态 FC，已经报告了许多与行为和疾病相关的具有显著意义的全脑模式。本初步研究利用一种新型的基于全头帽的高密度扩散光学断层扫描（DOT）技术，以及数据驱动的分析方法，研究了 13 名健康成年人在静息状态下自发血流信号波动中反复出现的短暂全脑模式。我们的结果报告称，少量（即 6 个）全脑共激活模式（CAP）描述了 DOT 记录的自发血流信号的主要时空动力学。这些 CAP 代表反复出现的大脑状态，表现出半球对称的空间拓扑结构，并且显示出高度的反相关对。此外，还确定了这六个脑状态之间的结构化过渡模式，其中两个具有前后空间模式的 CAP 显著参与了所有脑状态之间的过渡。我们的结果进一步阐明了两个大脑状态的全局正模式和负模式，分别表示整个皮层中短暂的神经元共激活和共去激活。我们证明这两个大脑状态是全局信号（GS）中部分峰值和低谷的产生原因，支持最近关于血流 GS 中神经元相关性的报告。总的来说，我们的结果表明，短暂的神经元事件（即 CAP）、全局大脑活动和全脑结构化转换在人类中同时存在，这些现象密切相关，这扩展了最近在动物血流数据中报告的类似神经元事件的观察结果。需要进行进一步的研究来了解这些短暂事件之间的定量关系及其与时间窗口 FC 之间的关系，以及更大的样本量，以了解它们与行为和疾病状况的变化。
