Huber Daniel, Rabl Luna, Orsini Chiara, Labek Karin, Viviani Roberto
Institute of Psychology, University of Innsbruck, Innsbruck, Austria.
Institute of Psychology, University of Innsbruck, Innsbruck, Austria; Psychiatry and Psychotherapy Clinic, University of Ulm, Ulm, Germany.
Neuroimage. 2024 Aug 15;297:120754. doi: 10.1016/j.neuroimage.2024.120754. Epub 2024 Jul 25.
The nature of the global signal, i.e. the average signal from sequential functional imaging scans of the brain or the cortex, is not well understood, but is thought to include vascular and neural components. Using resting state data, we report on the strong association between the global signal and the average signal from the part of the volume that includes the cranial bone and subdural vessels and venous collectors, separated from each other and the subdural space by multispectral segmentation procedures. While subdural vessels carried a signal with a phase delay relative to the cortex, the association with the cortical signal was strongest in the parts of the scan corresponding to the laminae of the cranial bone, reaching 80% shared variance in some individuals. These findings suggest that in resting state data vascular components may play a prominent role in the genesis of fluctuations of the global signal. Evidence from other studies on the existence of neural sources of the global signal suggests that it may reflect the action of multiple mechanisms (including cerebrovascular reactivity and autonomic control) concurrently acting to regulate global cerebral perfusion.
全球信号的本质，即大脑或皮层的连续功能成像扫描的平均信号，目前尚未完全了解，但据认为包括血管和神经成分。利用静息态数据，我们报告了全球信号与通过多光谱分割程序从包括颅骨、硬膜下血管和静脉收集器的体积部分获得的平均信号之间的强关联，这些部分通过多光谱分割程序相互分离并与硬膜下间隙分离。虽然硬膜下血管携带的信号相对于皮层存在相位延迟，但与皮层信号的关联在扫描中对应于颅骨板层的部分最强，在某些个体中达到80%的共享方差。这些发现表明，在静息态数据中，血管成分可能在全球信号波动的产生中起重要作用。其他关于全球信号神经源存在的研究证据表明，它可能反映了多种机制（包括脑血管反应性和自主控制）同时作用以调节全球脑灌注的作用。
