Interestingly, regions seemingly overlapping with the DMN have also been associated with retrieval of past events – or episodic memory retrieval. Event-related fMRI studies of episodic retrieval found that these regions show greater activity when previously studied items are correctly retrieved than when they are forgotten [15], [16], [17], [18], [19]. It has been suggested that these regions are involved in processes supporting successful retrieval [18]. In sharp contrast, fMRI studies focusing on the study phase of episodic memory – also referred to as memory encoding – suggest that the same regions are associated with unsuccessful encoding [20]. These studies found that these regions show less activity during encoding for items that are later remembered than for those that are forgotten [19], [21], [22], [23], [24]. We recently confirmed that these opposing patterns, of encoding decreases and retrieval increases, actually occur in overlapping brain regions [25]. Yet, the functional significance of this encoding/retrieval flip pattern, in relation to the DMN remains unclear.
