The default mode network (DMN), a set of brain regions active at rest, shows higher functional connectivity and stronger low-frequency fluctuations when people keep their eyes open (with or without a fixation point) than when they keep them closed. Although the overall connectivity patterns look similar across conditions, statistical comparisons reveal these differences. An order effect also appears: two eyes-closed sessions differ from each other. These findings suggest that having eyes open during rest may involve more non-specific visual gathering, evaluation, and mind wandering, and that researchers should carefully choose and order resting-state conditions in experimental designs.
The default mode network (DMN) and the frontal parietal network (FPN) mature at different rates in children, with the DMN reaching adult-like levels earlier than the FPN. In a longitudinal developmental fMRI study using an n-back task with 528 children and 103 young adults, children showed greater improvement over time but still performed worse than adults. Children had weaker DMN deactivation and FPN activation but stronger coupling between DMN and FPN regions. The coupling between the posterior cingulate cortex and dorsolateral prefrontal cortex mediated the relationship between age and working memory-related functional coupling, and together with task-invoked PCC activity, accounted for children's behavioral improvement. The DMN appears to provide a scaffolding effect supporting the immature FPN during executive function development.