This study investigates the functional connectivity between the posterior cingulate cortex (PCC) and the medial frontal region (MFG/vACC) during a working memory task and at rest. The PCC and MFG/vACC are often deactivated during cognitive tasks, suggesting they form part of a default mode network. However, the study found that these regions remain functionally connected during both the working memory task and at rest. Additionally, performance on the working memory task was positively correlated with the strength of this functional connection, both during the task and at rest. This suggests that these regions may facilitate or monitor cognitive performance rather than being disengaged during tasks. The findings also indicate that individual differences in the coupling strength between these regions at rest may predict differences in cognitive abilities relevant to working memory tasks. The study challenges the traditional view that interactions within the default mode network detract from cognitive performance and highlights the potential importance of this network in cognitive tasks.This study investigates the functional connectivity between the posterior cingulate cortex (PCC) and the medial frontal region (MFG/vACC) during a working memory task and at rest. The PCC and MFG/vACC are often deactivated during cognitive tasks, suggesting they form part of a default mode network. However, the study found that these regions remain functionally connected during both the working memory task and at rest. Additionally, performance on the working memory task was positively correlated with the strength of this functional connection, both during the task and at rest. This suggests that these regions may facilitate or monitor cognitive performance rather than being disengaged during tasks. The findings also indicate that individual differences in the coupling strength between these regions at rest may predict differences in cognitive abilities relevant to working memory tasks. The study challenges the traditional view that interactions within the default mode network detract from cognitive performance and highlights the potential importance of this network in cognitive tasks.