Resting-state signals in blood-oxygenation-level-dependent (BOLD) imaging are used to parcellate brain regions and define "functional connections" between regions. Yet a physiological link between fluctuations in blood oxygenation with those in neuronal signaling pathways is missing. We present evidence from studies on mouse cortex that modulation of vasomotion, i.e., intrinsic ultra-slow (0.1 Hz) fluctuations in arteriole diameter, provides this link. First, ultra-slow fluctuations in neuronal signaling, which occur as an envelope over γ-band activity, entrains vasomotion. Second, optogenetic manipulations confirm that entrainment is unidirectional. Third, co-fluctuations in the diameter of pairs of arterioles within the same hemisphere diminish to chance for separations >1.4 mm. Yet the diameters of arterioles in distant (>5 mm), mirrored transhemispheric sites strongly co-fluctuate; these correlations are diminished in acallosal mice. Fourth, fluctuations in arteriole diameter coherently drive fluctuations in blood oxygenation. Thus, entrainment of vasomotion links neuronal pathways to functional connections.

中文翻译：

---

神经活动引起的小动脉血管舒缩波动是血液氧合水平依赖性“恢复状态”的基础。

血液氧合水平依赖性（BOLD）成像中的静止状态信号用于分割大脑区域并定义区域之间的“功能连接”。仍然缺少血液氧合波动与神经元信号传导途径之间的生理联系。我们从小鼠皮质研究中获得的证据表明，血管运动的调制，即小动脉直径的固有超慢（0.1 Hz）波动，提供了这种联系。首先，神经元信号的超慢波动（作为对γ波段活动的包络而出现）会引起血管舒张。其次，光遗传学操作证实了夹带是单向的。第三，在同一半球内成对的小动脉直径的共同波动减小，从而导致间隔大于1.4毫米的机会。远处的小动脉直径（> 5 mm），镜像的跨半球位置强烈共波动；这些相关性在愈伤组织小鼠中减弱。第四，小动脉直径的波动连贯地驱动血液氧合的波动。因此，血管舒缩的夹带将神经通路与功能性连接联系起来。