Neural Correlates of Goal-Directed Preparation to Switching Across External and Internal Domains.

While it is well accepted that the human brain shifts between internal and external monitoring both during tasks and at rest, no task-switching studies have focused on brain changes when switching from and to self-referential processing. Using a cued task-switching design, we explored the preparatory fMRI activation associated with switching not only within externally oriented tasks, but also within self-referential tasks, as well as between these two domains. We found that preparing to perform internal tasks activated the default mode network, while preparing for external tasks activated regions of the dorsal attention network (DAN). Switch preparation activated left-lateralised DAN regions with ventrolateral peaks as well as dorsal precuneus, posterior cingulate and supplementary motor area. These results show a dynamic pattern of communication across networks associated with external and internal domain processing and common preparatory activation in working memory and executive control regions. In particular, the dorsal precuneus was consistently engaged in task-switch preparation, suggesting a key role of this region in cognitive control, in the context of switching across external and internal domains.