*3.1. Overview of DMN*

The DMN was initially described as brain regions that consistently showed synchronized deactivation during tasks and activation during rest [79]. This network now generally includes the medial prefrontal cortices (mPFCs), the posterior cingulate cortex (PCC), precuneus, inferior parietal lobule, lateral temporal cortex, and hippocampal formation [80,81]. The DMN is known to be normally deactivated during complex cognitive processing and active during rest, and further studies found that DMN activity is associated with internal processes, such as self-referential thinking [82], autobiographical memory [83], or thinking about the future [84]. Previous meta-analyses, including studies measuring ReHo, ALFF, and fALFF, suggested that altered DMN connectivity seems robust to the choice of analytical methods [85]. The DMN is generally divided into an anterior subdivision centered on the mPFC and a posterior subdivision centered on the PCC and the precuneus cortex [80,86]. Although both the anterior and posterior parts of the DMN are related to spontaneous or self-generated cognition, they seem to be different according to their specific functions [86,87]. Generally, the anterior DMN is more related to self-referential processing and emotion regulation, partly through its strong connections with limbic areas, and the posterior DMN has been implicated in both consciousness and memory processing through its relation to the hippocampal formation [87,88].
