Neuroimaging studies have identified a network of brain regions, including ventral parietal, posterior cingulate, medial frontal, and hippocampal regions, which have been consistently linked to conscious rest. These regions show more activity during passive baseline than active task conditions [1], [2], [3] and also show strong coherence during rest [4], [5], [6]. According to an influential theory, the default mode hypothesis, these regions form a default mode network (DMN) engaged in specific processes that normally occur during the conscious resting state [7]. This hypothesis further holds that DMN regions are continuously active, but momentarily shut down when available resources are needed for efficient cognitive performance, giving rise to deactivation in these areas. The interest in the functional significance of the DMN has increased by indications of deviations from normal DMN activity in various clinical populations, including patients with Alzheimer's dementia [8], [9], [10], [11], schizophrenia [12], [13], and autism [14]. Yet, despite all this interest, there is still considerable debate about the specific cognitive processes that are mediated by the DMN.
