Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA.
Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA.
Neuron. 2018 Apr 18;98(2):297-305.e6. doi: 10.1016/j.neuron.2018.03.015. Epub 2018 Mar 29.
Systems-level organization in spontaneous infra-slow (<0.1Hz) brain activity, measured using blood oxygen signals in fMRI and optical imaging, has become a major theme in the study of neural function in both humans and animal models. Yet the neurophysiological basis of infra-slow activity (ISA) remains unresolved. In particular, is ISA a distinct physiological process, or is it a low-frequency analog of faster neural activity? Here, using whole-cortex calcium/hemoglobin imaging in mice, we show that ISA in each of these modalities travels through the cortex along stereotypical spatiotemporal trajectories that are state dependent (wake versus anesthesia) and distinct from trajectories in delta (1-4 Hz) activity. Moreover, mouse laminar electrophysiology reveals that ISA travels through specific cortical layers and is organized into unique cross-laminar temporal dynamics that are different from higher frequency local field potential activity. These findings suggest that ISA is a distinct neurophysiological process that is reflected in fMRI blood oxygen signals.
自发超慢（<0.1Hz）脑活动的系统水平组织，使用 fMRI 和光学成像中的血氧信号进行测量，已成为人类和动物模型中神经功能研究的主要主题。然而，超慢活动（ISA）的神经生理学基础仍未解决。特别是，ISA 是一种独特的生理过程，还是更快神经活动的低频模拟？在这里，我们使用小鼠全皮层钙/血红蛋白成像表明，这两种模式中的每一种 ISA 都沿着与 delta（1-4 Hz）活动轨迹不同的、依赖状态（清醒与麻醉）的典型时空轨迹在皮层中传播。此外，小鼠层状电生理学揭示了 ISA 穿过特定的皮层层，并组织成独特的跨层时间动态，与更高频率的局部场电位活动不同。这些发现表明，ISA 是一种独特的神经生理过程，在 fMRI 血氧信号中得到反映。
