Proceedings of the National Academy of Sciences of the United States of America
May 26, 2009
Kalina Christoff, Alan M Gordon, Jonathan Smallwood et al.
1,832 citations
Mind wandering, which occupies a large portion of waking life, involves parallel recruitment of both default and executive brain networks, two systems previously thought to work in opposition. Using fMRI with experience sampling during a task, activation in default network regions, particularly medial prefrontal cortex, was linked to subjective reports of mind wandering and to performance errors. Executive network recruitment also occurred, especially when participants lacked meta-awareness of their mind wandering. The findings suggest that mind wandering represents a unique mental state where these networks cooperate rather than oppose each other.
Frontiers in human neuroscience
January 1, 2013
Micah Allen, Jonathan Smallwood, Joanna Christensen et al.
100 citations
Mind-wandering, or task-unrelated thoughts (TUTs), is common and often impairs performance on demanding tasks, but new findings show it can also enhance metacognitive abilities. Using the Error Awareness Task (EAT), researchers found that individual differences in average TUTs strongly predicted stop accuracy, while variability in TUTs specifically predicted error awareness. Brain imaging revealed that both response inhibition and TUT ratings activated the medial prefrontal cortex (mPFC) of the default mode network (DMN), but in distinct dorsal areas, suggesting functional segregation. Co-activation of salience and default mode regions during error awareness linked monitoring to TUTs. The results suggest that fluctuations between internal and external thought, rather than constant focus, characterize individuals with greater metacognitive monitoring, and balancing these modes may optimize task performance.
bioRxiv (Cold Spring Harbor Laboratory)
May 3, 2020
Manesh Girn, Leor Roseman, Boris C. Bernhardt et al.
27 citations
preprint
LSD and psilocybin flatten the brain's hierarchical organization, reducing the functional separation between sensory and higher-order cognitive networks. Using a non-linear dimensionality reduction technique on resting-state fMRI data, the authors found that both drugs compressed the principal gradient of cortical connectivity, which normally spans from unimodal (sensory) to transmodal (association) cortex. This flattening was driven by decreased differentiation at both ends of the hierarchy—default and frontoparietal networks at the upper end and somatomotor networks at the lower end—and was accompanied by increased crosstalk between unimodal and transmodal regions. Changes in the principal gradient under LSD tracked self-reported ego-dissolution. The findings support a mechanistic model of the psychedelic state and demonstrate that macroscale connectivity gradients are sensitive to serotonergic modulation.
Consciousness and cognition
February 1, 2025
Anusha Garg, Shivang Shelat, Madeleine E Gross et al.
13 citations
Thinking aloud while letting the mind wander does not substantially alter the stream of consciousness compared to thinking silently. In two studies with 111 and 102 participants, people who verbalized their ongoing thoughts showed no significant differences in meta-awareness or how often their topics shifted. Of 21 thought qualities and 18 content topics examined, only three qualities (private thoughts, mind blanking, and session difficulty) and one topic (partner, intimacy, love, and sexual matters) differed between conditions. Cognitive load also did not differ. The findings indicate that the Think Aloud method is a reliable and minimally reactive tool for studying the natural flow of thoughts in task-absent settings.