BOLD信号会随着时间而出现波动，即BOLD信号的时间变化性（BOLD signal temporal variability, BSTV）。BSTV不仅能够影响个体对外界刺激的感知，还是功能连接的基础，对其机制的深入探讨对人们理解高级认知功能的神经机制具有重要作用。一个有趣的现象是，不同视觉刺激状态下，BSTV的改变方向与局部脑血流的改变方向相反。本项目拟以此作为突破口研究BSTV的神经机制，首先探讨不同感觉通道不同的刺激水平下，BSTV的改变与局部脑血流改变之间的关系。随后，以严重意识障碍病人和健康成人为对象，探索脑内抑制性系统（GABA能系统）的参与如何对BSTV改变与局部脑血流改变之间的关系产生作用。本项目的实施，不仅为理解外界刺激诱发脑活动的神经机制提供新的见解和研究思路。同时，将深化对神经活动的时间变化性与高级认知功能之间关系的理解，也有助于揭示严重意识障碍病人的神经机制。

Blood Oxygenation Level Dependent (BOLD) signal varies continually from moment to moment, which can be termed BOLD signal temporal variability (BSTV). BSTV is the basis of brain network analysis, and could affect the perception of the external stimuli. BSTV has been shown to affect the perception of the external stimuli and forms the basis for fMRI functional connectivity analyses. As such, BSTV forms a key component for understanding the neural mechanisms of high-level cognitive functions. One interesting phenomenon shows that when switching between different conditions, the concomitant changes of BSTV and cerebral blood flow (CBF) go into opposite directions. Understanding this phenomenon may help people to discover the neural mechanism of BSTV. So the current project will firstly investigate the direct relationship between the changes in BSTV and CBF between different stimulus conditions in different sensory modalities. Following on from this, we will aim to investigate how the brain's GABAergic inhibitory processes mediate the relationship between the changes of BSTV and CBF from condition to condition. Together, these investigations will provide news idea about eternally-evoked sensory responses. Furthermore, these investigations will extend our understanding about the relationship between BSTV and high-cognitive functions, and also be helpful to understand the neural mechanism of disorders of consciousness.