The default mode network, typically linked to internally-directed thoughts like mind wandering, shows reduced activity during many cognitive tasks. However, this network can become more active during a large and demanding switch in task set. Using multivoxel pattern analysis, the authors found that regions within the default mode network encode task-relevant information during task performance. Activity in this network may be driven by major revisions of cognitive context, whether internally or externally focused.
The default mode network (DMN) is typically thought to support internally focused thought, but a new brain imaging study shows it also activates during certain external task switches. Using fMRI, 24 participants performed a task-switching experiment. The DMN increased activity not only during task switches, replicating prior findings, but also during brief rests and task restarts after rest. These results challenge theories that restrict DMN function to internal or self-directed cognition. The authors propose that the DMN encodes scene, episode, or context by integrating spatial, self-referential, and temporal information. Context representations are strong at rest, but re-reference to context also occurs at major cognitive transitions.