Wandering minds: the default network and stimulus-independent thought

Abstract

Despite evidence pointing to a ubiquitous tendency of human minds to wander, little is known about the neural operations that support this core component of human cognition. Using both thought sampling and brain imaging, the current investigation demonstrated that mind-wandering is associated with activity in a default network of cortical regions that are active when the brain is "at rest." In addition, individuals' reports of the tendency of their minds to wander were correlated with activity in this network.

Fig. 1

Graphs depict regions of the default network exhibiting significantly greater activity during practiced blocks (red) relative to novel blocks (blue) at a threshold of P < 0.001, number of voxels (k) = 10. Mean activity was computed for each participant by averaging the signal in regions within 10 mm of the peak, across the duration of the entire block. Graphs depict the mean signal change across all participants. (A) Left (L.) mPFC (BA 9; –6, 54, 22); (B) BXXX (B.) cingulate (BA 24; 0, –7, 36); (C) Right (R.) insula (45, –26, 4); and (D) L. posterior cingulate (BA 23/31; –9, –39, 27). Activity is plotted on the average high-resolution anatomical image and displayed in neurological convention (left hemisphere is depicted on the left).

Fig. 2

Graphs depict regions that exhibited a significant positive relation, r(14) > 0.50, P < 0.05, between the frequency of mind-wandering and the change in BOLD signal observed when people performed practiced relative to novel blocks. Participants’ BOLD difference scores (practiced – novel) are plotted against their standardized IPI daydreaming score. BOLD signal values for the two blocks were computed for each participant by averaging the signal in regions within 10 mm of the peak, from 4 TRs (10 s) until 10 TRs (22.5 s) after the block onset. (A) B. mPFC (BA 10; –6, 51, –9; k = 25); (B) B. precuneus and p. cingulate (BA 31, 7; –3, –45, 37; k = 72); (C) R. cingulate (BA 31; 7, –21, 51; k = 73); (D) L. insula (BA 13; –36, –16, 17; k = 10); (E) R. insula (BA 13; 47, 0, 4; k = 13). Activity is plotted on the average high-resolution anatomical image and displayed in neurological convention (left hemisphere is depicted on the left).