Department of Diagnostic Radiology, Yale School of Medicine, New Haven, CT 06511, USA.
Magn Reson Imaging. 2010 Oct;28(8):1051-7. doi: 10.1016/j.mri.2010.03.021. Epub 2010 Apr 21.
Functional brain imaging studies have identified a set of brain areas typically activated during cognitive tasks (task-positive brain areas) and another set of brain areas typically deactivated during cognitive tasks (task-negative brain areas). Negative correlations, or anticorrelations, between task-positive and task-negative brain areas have been reported at rest. Furthermore, the strength of these anticorrelations appears to be related to cognitive function. However, studies examining anticorrelations have typically employed global regression or similar analysis steps that force anticorrelated relationships to exist between brain areas. Therefore the validity of these findings has been questioned. Here we examine anticorrelations between a task-negative region in the medial frontal gyrus/anterior cingulate cortex and dorsolateral prefrontal cortex, a classic task-positive area, using an analysis that does not include global regression. Instead, we control for whole-brain correlations in the group-level analysis. Using this approach, we demonstrate that the strength of the functional connection between the medial frontal cortex and the dorsolateral prefrontal cortex is related to cognitive function and that this relationship is not an artifact of global regression.
功能脑成像研究已经确定了一组在认知任务中通常被激活的脑区（任务正相关脑区）和另一组在认知任务中通常被抑制的脑区（任务负相关脑区）。在静息状态下，已经报道了任务正相关和任务负相关脑区之间的负相关或反相关。此外，这些反相关的强度似乎与认知功能有关。然而，研究反相关的研究通常采用全局回归或类似的分析步骤，这些步骤迫使脑区之间存在反相关关系。因此，这些发现的有效性受到了质疑。在这里，我们使用一种不包括全局回归的分析方法，研究了内侧额回/前扣带皮层与背外侧前额叶皮层之间的任务负相关区域，这是一个经典的任务正相关区域。相反，我们在组水平分析中控制了全脑相关性。通过这种方法，我们证明了内侧额皮质和背外侧前额叶皮质之间的功能连接强度与认知功能有关，而且这种关系不是全局回归的假象。
