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.
Neuroimage
January 12, 2018
Charlotte Murphy, Elizabeth Jefferies, Shirley-Ann Rueschemeyer et al.
288 citations
The default mode network supports cognition independent of immediate environment and higher-order conceptual representations. A novel paradigm manipulated perceptual information availability and representational complexity during decision-making. Brain regions including left and right angular gyri and left middle temporal gyrus responded when cognition combined stimulus independence with multi-modal information. These default mode network sites showed stronger response to demanding memory judgments than easier perceptual tasks, contradicting the view they support automatic cognition. These regions were at the extreme end of a macroscale gradient from sensorimotor to transmodal cortex, suggesting functional distance from sensory input enables conceptually rich cognitive states in absence of input.
Nature Communications
August 23, 2019
Adam Turnbull, Hao-ting Wang, Charlotte Murphy et al.
197 citations
When a task is undemanding, people often let their minds wander to personally relevant thoughts. The dorsolateral prefrontal cortex (DLPFC), a brain region known for maintaining goal representations, also helps prioritize off-task thinking. Neural activity in the DLPFC was high both when people were on-task under demanding conditions and off-task during a non-demanding task. Individuals who increased off-task thought when external demands decreased showed weaker correlation between neural signals linked to external tasks and lateral default mode network regions within the DLPFC, and had less cortical grey matter in regions sensitive to those external signals. The findings suggest that humans use the DLPFC to align cognition with personal goals when environmental demands drop, prioritizing daydreaming.
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.
Neuroimage
June 22, 2020
Brontë Mckeown, Will Strawson, Hao-ting Wang et al.
102 citations
People whose brain connectivity patterns make the sensorimotor system most distinct from the visual system are more likely to report thoughts about solving problems or goals and less likely to report thoughts about the past. This finding comes from a study where participants underwent resting-state fMRI and then completed a questionnaire about their thoughts during the scan. A non-linear dimension reduction algorithm identified components explaining the greatest variance in whole-brain connectivity patterns. The results suggest that unique patterns of experience are linked to distinct neurocognitive profiles, with unimodal systems playing an important role.
PLoS One
August 25, 2016
Jonathan Smallwood, Theodoros Karapanagiotidis, Florence Ruby et al.
Spontaneous thoughts about absent people, places, or events arise from interactions within the default mode network (DMN). The posterior cingulate cortex, a core DMN region, integrates information from medial and lateral temporal lobe memory systems, which represent different aspects of knowledge. Individual differences in connectivity between temporal lobe regions and the DMN core predict the content and form of people's spontaneous thoughts. In a laboratory study, variations in functional connectivity from both medial and lateral temporal lobe regions were associated with different patterns of spontaneous thought, converging on an overlapping region in the posterior cingulate cortex. The posterior DMN core acts as a representational hub that integrates temporal lobe information, shaping spontaneous thought.