Department of Radiology, Washington University, St. Louis, Missouri;
Department of Radiology, Washington University, St. Louis, Missouri; Department of Neurology, Washington University, St. Louis, Missouri.
J Neurophysiol. 2014 Jun 1;111(11):2374-91. doi: 10.1152/jn.00804.2013. Epub 2014 Mar 5.
The discovery that spontaneous fluctuations in blood oxygen level-dependent (BOLD) signals contain information about the functional organization of the brain has caused a paradigm shift in neuroimaging. It is now well established that intrinsic brain activity is organized into spatially segregated resting-state networks (RSNs). Less is known regarding how spatially segregated networks are integrated by the propagation of intrinsic activity over time. To explore this question, we examined the latency structure of spontaneous fluctuations in the fMRI BOLD signal. Our data reveal that intrinsic activity propagates through and across networks on a timescale of ∼1 s. Variations in the latency structure of this activity resulting from sensory state manipulation (eyes open vs. closed), antecedent motor task (button press) performance, and time of day (morning vs. evening) suggest that BOLD signal lags reflect neuronal processes rather than hemodynamic delay. Our results emphasize the importance of the temporal structure of the brain's spontaneous activity.
血氧水平依赖（BOLD）信号自发性波动中包含有关大脑功能组织信息的发现，引发了神经影像学的范式转变。现在已经明确，内在脑活动组织成空间分离的静息态网络（RSN）。关于如何通过内在活动的传播随时间整合空间分离的网络，人们了解较少。为了探索这个问题，我们检查了 fMRI BOLD 信号中自发性波动的潜伏期结构。我们的数据显示，内在活动在 ∼1 秒的时间尺度内通过和跨网络传播。由于感觉状态操纵（睁眼与闭眼）、前导运动任务（按钮按压）表现和一天中的时间（早晨与傍晚）而导致的这种活动的潜伏期结构变化表明，BOLD 信号延迟反映了神经元过程，而不是血液动力学延迟。我们的结果强调了大脑自发性活动的时间结构的重要性。
