Involvement of the default mode network under varying levels of cognitive effort
Scientific Reports April 15, 2022 S. Weber, A. Aleman, K. Hugdahl
The brain's default mode network (DMN), traditionally considered a resting-state network, is also active during low-effort cognitive tasks. Using fMRI and a Stroop paradigm, participants alternated between rest, low effort (word reading), and high effort (color naming). The DMN was more active during low effort than high effort, suggesting gradual up- and down-regulation based on cognitive demand. The anti-correlation between the DMN and the extrinsic mode network (EMN) was strongest during low effort, indicating both networks contribute to low-effort processing. These findings challenge the view of the DMN as solely task-negative; instead, both networks may support low-effort cognition, while rest and high effort are dominated by the DMN and EMN, respectively.