University of Liège, Liège, Belgium.
J Cogn Neurosci. 2011 Mar;23(3):570-8. doi: 10.1162/jocn.2010.21488. Epub 2010 Jun 1.
Evidence from functional neuroimaging studies on resting state suggests that there are two distinct anticorrelated cortical systems that mediate conscious awareness: an "extrinsic" system that encompasses lateral fronto-parietal areas and has been linked with processes of external input (external awareness), and an "intrinsic" system which encompasses mainly medial brain areas and has been associated with internal processes (internal awareness). The aim of our study was to explore the neural correlates of resting state by providing behavioral and neuroimaging data from healthy volunteers. With no a priori assumptions, we first determined behaviorally the relationship between external and internal awareness in 31 subjects. We found a significant anticorrelation between external and internal awareness with a mean switching frequency of 0.05 Hz (range: 0.01-0.1 Hz). Interestingly, this frequency is similar to BOLD fMRI slow oscillations. We then evaluated 22 healthy volunteers in an fMRI paradigm looking for brain areas where BOLD activity correlated with "internal" and "external" scores. Activation of precuneus/posterior cingulate, anterior cingulate/mesiofrontal cortices, and parahippocampal areas ("intrinsic system") was linearly linked to intensity of internal awareness, whereas activation of lateral fronto-parietal cortices ("extrinsic system") was linearly associated with intensity of external awareness.
静息态功能神经影像学研究的证据表明，存在两个截然不同的负相关皮质系统来介导意识：一个“外在”系统，包括外侧额顶叶区域，与外部输入过程有关（外部意识），以及一个“内在”系统，主要包括内侧脑区，与内部过程有关（内部意识）。我们的研究旨在通过提供健康志愿者的行为和神经影像学数据来探索静息态的神经相关性。我们没有先验假设，首先在 31 名受试者中确定了外部和内部意识之间的行为关系。我们发现外部和内部意识之间存在显著的负相关，平均切换频率为 0.05Hz（范围：0.01-0.1Hz）。有趣的是，这个频率类似于 BOLD fMRI 慢波。然后，我们在 fMRI 范式中评估了 22 名健康志愿者，寻找与“内部”和“外部”评分相关的大脑区域的 BOLD 活动。楔前叶/后扣带回、前扣带回/中额皮质和海马旁区的激活（“内在系统”）与内部意识的强度呈线性相关，而外侧额顶叶皮质的激活（“外在系统”）与外部意识的强度呈线性相关。
