Proceedings of the National Academy of Sciences
August 27, 2018
Mladen Sormaz, Charlotte Murphy, Hao-ting Wang et al.
291 citations
The default mode network (DMN), a set of brain regions traditionally linked to off-task or mind-wandering states, actually contributes to detailed, task-relevant cognition during active tasks. Using fMRI, participants performed working-memory tasks while reporting their thoughts. Patterns of neural activity showed that distinctions between on- and off-task thought involved regions near sensory and motor cortex, not the DMN. However, the level of detail in ongoing thought corresponded to activity patterns within the DMN during memory maintenance. These findings indicate the DMN supports detailed cognition under active task conditions, challenging the view that it is solely task-negative.
Social Cognitive and Affective Neuroscience
March 21, 2017
Giulia Poerio, Mladen Sormaz, Hao-ting Wang et al.
185 citations
Mind-wandering involves cognition detached from the immediate environment. The default mode network (DMN), a set of brain regions far from sensory and motor areas, is implicated but its exact role is unclear. This study examined how individual differences in resting-state DMN connectivity relate to performance on memory, social, and planning tasks and to variability in spontaneous thought. Poor external engagement was linked to stronger coupling between medial and dorsal DMN subsystems, while decoupling of the core from the cerebellum predicted detailed memory retrieval. Both patterns predicted off-task future thoughts. The DMN supports stimulus-independent cognition through strong subsystem coupling and allows memory representations to form conscious experience.
iScience
February 2, 2021
Jonathan Smallwood, Adam Turnbull, Hao-ting Wang et al.
130 citations
The landscape of ongoing thought is heterogeneous and shaped by both personal traits and environmental context. Recent work shows that attention and control systems organize experience in response to changing demands, while the default mode network contributes not only to task-negative or episodic content but also to the vividness of experience in both task contexts and spontaneous self-generated states. Multiple neural systems reflect the landscape of ongoing thought, and it is important to distinguish processes that shape how experience unfolds from those that regulate it.
Scientific Reports
December 3, 2020
Theodoros Karapanagiotidis, Diego Vidaurre, Andrew J. Quinn et al.
82 citations
When people are not engaged in an explicit task, they experience a variety of self-generated thoughts, such as planning or reminiscing. Using machine learning to analyze brain activity from resting-state fMRI scans, researchers identified distinct neural states that recur over time. Two of these states predicted different patterns of thinking. One neural state, resembling activity seen during demanding tasks, was linked to problem-solving about the future. Another state, associated with less demanding conditions, was tied to intrusive thoughts about the past. These two states fell at opposite ends of a brain hierarchy related to cognitive demand. The findings show that tracking moment-to-moment changes in brain function can help classify self-generated mental states and that these states align with the brain's response to cognitive tasks.
Journal of Sleep Research
July 27, 2016
Dan Denis, Giulia Poerio
70 citations
Sleep paralysis and lucid dreaming are both dissociated states linked to REM sleep. A survey of 1928 adults (ages 18–82, 53% female) found that more frequent lucid dreaming is associated with more frequent sleep paralysis, especially episodes involving vestibular-motor hallucinations. Dissociative experiences during wakefulness predicted both phenomena. However, sleep paralysis was predicted by poor sleep quality, anxiety, and life stress, whereas lucid dreaming was predicted by a tendency toward positive, constructive daydreaming and vivid sensory imagery. The findings suggest that dissociative tendencies during wakefulness extend into REM sleep, but sleep paralysis reflects sleep and well-being issues, while lucid dreaming may stem from greater imaginative capacity and positive imagery in waking life.
Sleep
December 13, 2018
Dan Denis, Giulia Poerio, Sarah Derveeuw et al.
25 citations
Exploding head syndrome, a sensory parasomnia where people perceive loud noises or a sense of explosion when falling asleep or waking, affects about 10-15% of individuals, with significant fear in some cases. Across two samples—199 female undergraduates and 1,683 international participants aged 18-82—lifetime prevalence was 37.19% and 29.59%, respectively, with monthly episodes in 6.54% and 3.89%. Insomnia symptoms and sleep paralysis frequency were consistently linked to the condition in multiple logistic regression models. In the larger sample, dissociative experiences during wakefulness and nightmares also showed associations. These findings offer initial insights into factors related to exploding head syndrome.