Department of Psychology, Harvard University, Cambridge, MA 02138, USA.
Cereb Cortex. 2010 Aug;20(8):1997-2006. doi: 10.1093/cercor/bhp270. Epub 2009 Dec 21.
The resting brain is associated with significant intrinsic activity fluctuations, such as the correlated low-frequency (LF) blood oxygen level-dependent (BOLD) fluctuations measured by functional magnetic resonance imaging. Despite a recent expansion of studies investigating resting-state LF-BOLD correlations, their nature and function are poorly understood. A major constraint on LF-BOLD correlations appears to be stable properties of anatomic connectivity. There is also evidence that coupling can be modulated by recent or ongoing task performance, suggesting that certain components of correlated dynamics are malleable on short timescales. Here, we compared activity during extended periods of rest following performance of 2 distinct cognitive tasks using different categories of visual stimuli-faces and complex scenes. Prolonged exposure to these distinct categories of visual information caused frontal networks to couple differentially with posterior category-preferential visual regions during subsequent periods of rest. In addition, we report preliminary evidence suggesting that conditions exist in which the degree of modulation of LF-BOLD correlations predicts subsequent memory. The finding that resting-state LF-BOLD correlations are modulated by recent experience in functionally specific brain regions engaged during prior task performance clarifies their role as a dynamic phenomenon which may be involved in mnemonic processes.
静息态大脑与显著的固有活动波动相关,例如功能磁共振成像测量的相关低频(LF)血氧水平依赖(BOLD)波动。尽管最近对静息态 LF-BOLD 相关性的研究有所扩展,但它们的性质和功能仍知之甚少。LF-BOLD 相关性的一个主要限制似乎是解剖连接的稳定特性。也有证据表明,耦合可以通过最近或正在进行的任务表现来调节,这表明相关动力学的某些成分在短时间尺度上是可塑的。在这里,我们比较了在执行 2 种不同认知任务后,使用不同类别的视觉刺激(面孔和复杂场景)进行长时间休息期间的活动。长时间接触这些不同类别的视觉信息会导致额叶网络在随后的休息期间与后位类别偏好视觉区域不同程度地耦合。此外,我们报告了初步证据表明,存在这样的条件,即 LF-BOLD 相关性的调制程度可以预测随后的记忆。静息态 LF-BOLD 相关性受先前任务执行过程中参与的特定功能脑区的近期经验调制的发现,阐明了它们作为一种动态现象的作用,可能与记忆过程有关。