Endogenous brain states that have been linked to inattention to sensory stimuli are often referred to as “resting states.” Both functional connectivity analysis and independent component analysis (ICA) of fMRI data have identified many consistent resting-state networks (De Luca et al., 2006; Fox et al., 2007). These networks are characterized by “infra-slow” fluctuations on the order of 0.01–0.1 Hz (Palva and Palva, 2012) and can be observed by recording fMRI on undirected subjects while they lie in the scanner doing no specific task. The most extensively studied of these is the default-mode network (DMN), a co-activation of the posterior cingulate cortex, medial prefrontal cortex, and angular gyri that was originally defined to represent a baseline brain state (Raichle et al., 2001). It is commonly associated with self-monitoring, auto-biographical, and social functions, reflecting attention to the internal world (Bressler and Menon, 2010). However, recent work has uncovered evidence for a more active role of the DMN related to task performance (Eichele et al., 2008), including its deactivation by cognitive load during task engagement (Esposito et al., 2006).
