Distinct individual differences in default mode network connectivity relate to off-task thought and text memory during reading

People often find their thoughts drifting away from the text they are reading, a tendency known as mind-wandering, which impairs comprehension and memory for the text. Using fMRI, the study found that individuals with poorer memory for texts show reduced activity in the left middle temporal gyrus in response to written input. This region sits at the intersection of the default mode, dorsal attention, and frontoparietal networks. In a resting-state analysis, stronger connectivity within the default mode network was associated with better text memory, while greater decoupling between the default mode network and medial visual regions was linked to more frequent mind-wandering. These results suggest that intrinsic brain network connectivity influences how attention stays engaged with reading.

Study at a glance

Abstract

Often, as we read, we find ourselves thinking about something other than the text; this tendency to mind-wander is linked to poor comprehension and reduced subsequent memory for texts. Contemporary accounts argue that periods of off-task thought are related to the tendency for attention to be decoupled from external input. We used fMRI to understand the neural processes that underpin this phenomenon. First, we found that individuals with poorer text-based memory tend to show reduced recruitment of left middle temporal gyrus in response to orthographic input, within a region located at the intersection of default mode, dorsal attention and frontoparietal networks. Voxels within these networks were taken as seeds in a subsequent resting-state study. The default mode network region (i) had greater connectivity with medial prefrontal cortex, falling within the same network, for individuals with better text-based memory, and (ii) was more decoupled from medial visual regions in participants who mind-wandered more frequently. These findings suggest that stronger intrinsic connectivity within the default mode network is linked to better text processing, while reductions in default mode network coupling to the visual system may underpin individual variation in the tendency for our attention to become disengaged from what we are reading.