The Default Mode Network of the Brain Underlies Mind Wandering
By John M. de Castro, Ph.D.
“the brain appears to support mind wandering by disrupting some of the brain processes that are involved in responding to our surrounding external environment.” – Julia Kam
We spend a tremendous amount of waking time with our minds wandering and not on the present environment or the task at hand. We daydream, plan for the future, review the past, ruminate on our failures, exalt in our successes. In fact, we spend almost half of our waking hours off task with our mind wandering. A system of the brain known as the Default Mode Network (DMN) becomes active during wind wandering and relatively quiet during focused on task behavior. Meditation is known to reduce the size, connectivity, and activity of the Default Mode Network (DMN).
In today’s Research News article “Lesion network mapping demonstrates that mind-wandering is associated with the default mode network.” (See summary below or view the full text of the study at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7704688/ ) Philippi and colleagues recruited patients with circumscribed brain injuries (lesions) and age and education matched non-brain damaged comparison participants. They all underwent brain scanning with Magnetic Resonance Imaging (MRI). They completed a self-report measure of mind wandering.
They found that the brain damaged patients had lower frequencies of mind wandering than the healthy comparison participants. They then examined the specific brain areas damaged in the patients lesions and related it to their reduced mind wandering scores. They found that reduced mind wandering was associated with structures in the Default Mode Network (DMN), including the medial prefrontal cortex, parietal lobe, and inferior frontal gyrus.
The results are simple and straightforward and suggest that damage to the Default Mode Network (DMN) reduces mind wandering. This finding taken together with the findings that the DMN becomes more active during mind wandering makes a clear case that the DMN is responsible for mind wandering.
So, the default mode network of the brain underlies mind wandering.
“mind-wandering was associated with increased DMN activity and increased DMN-VS connectivity.“ – Xinqi Zhou
CMCS – Center for Mindfulness and Contemplative Studies
This and other Contemplative Studies posts are also available on Google+ https://plus.google.com/106784388191201299496/posts and on Twitter @MindfulResearch
Philippi, C. L., Bruss, J., Boes, A. D., Albazron, F. M., Deifelt Streese, C., Ciaramelli, E., Rudrauf, D., & Tranel, D. (2021). Lesion network mapping demonstrates that mind-wandering is associated with the default mode network. Journal of neuroscience research, 99(1), 361–373. https://doi.org/10.1002/jnr.24648
Functional neuroimaging research has consistently associated brain structures within the default mode network (DMN) and frontoparietal network (FPN) with mind-wandering. Targeted lesion research has documented impairments in mind-wandering after damage to the medial prefrontal cortex (mPFC) and hippocampal regions associated with the DMN. However, no lesion studies to date have applied lesion network mapping to identify common networks associated with deficits in mind-wandering. In lesion network mapping, resting-state functional connectivity data from healthy participants are used to infer which brain regions are functionally connected to each lesion location from a sample with brain injury. In the current study, we conducted a lesion network mapping analysis to test the hypothesis that lesions affecting the DMN and FPN would be associated with diminished mind-wandering. We assessed mind-wandering frequency on the Imaginal Processes Inventory (IPI) in participants with brain injury (n = 29) and healthy comparison participants without brain injury (n = 19). Lesion network mapping analyses showed the strongest association of reduced mind-wandering with the left inferior parietal lobule within the DMN. In addition, traditional lesion symptom mapping results revealed that reduced mind-wandering was associated with lesions of the dorsal, ventral, and anterior sectors of mPFC, parietal lobule, and inferior frontal gyrus in the DMN (p < 0.05 uncorrected). These findings provide novel lesion support for the role of the DMN in mind-wandering and contribute to a burgeoning literature on the neural correlates of spontaneous cognition.
Adults spend up to 50% of their waking day mind-wandering, which is the process of turning one’s attention inward to focus on self-generated thoughts or feelings. Mind-wandering can have both costs and benefits, such as increased negative mood or enhanced creative problem-solving. In this study, we report novel findings linking reduced mind-wandering with brain injury located within the default mode network. This work is important because it can help us to determine which brain networks are necessary for self-generated cognition, which may improve our understanding of neuropsychiatric conditions associated with altered self-focused thought.