scholarly journals The Functional Convergence and Heterogeneity of Social, Episodic, and Self-Referential Thought in the Default Mode Network

2020 ◽  
Vol 30 (11) ◽  
pp. 5915-5929 ◽  
Author(s):  
Tanya Wen ◽  
Daniel J Mitchell ◽  
John Duncan
Keyword(s):  
Default Mode Network ◽  
Medial Temporal Lobe ◽  
Brain Activity ◽  
Activity Patterns ◽  
Univariate Analysis ◽  
Moral Dilemmas ◽  
Default Mode ◽  
Multiple Components ◽  
Common Activity ◽  
Rest Condition

Abstract The default mode network (DMN) is engaged in a variety of cognitive settings, including social, semantic, temporal, spatial, and self-related tasks. Andrews-Hanna et al. (2010; Andrews-Hanna 2012) proposed that the DMN consists of three distinct functional–anatomical subsystems—a dorsal medial prefrontal cortex (dMPFC) subsystem that supports social cognition; a medial temporal lobe (MTL) subsystem that contributes to memory-based scene construction; and a set of midline core hubs that are especially involved in processing self-referential information. We examined activity in the DMN subsystems during six different tasks: 1) theory of mind, 2) moral dilemmas, 3) autobiographical memory, 4) spatial navigation, 5) self/other adjective judgment, and 6) a rest condition. At a broad level, we observed similar whole-brain activity maps for the six contrasts, and some response to every contrast in each of the three subsystems. In more detail, both univariate analysis and multivariate activity patterns showed partial functional separation, especially between dMPFC and MTL subsystems, though with less support for common activity across the midline core. Integrating social, spatial, self-related, and other aspects of a cognitive situation or episode, multiple components of the DMN may work closely together to provide the broad context for current mental activity.

scholarly journals The functional convergence and heterogeneity of social, episodic, and self-referential thought in the default mode network

2019 ◽  
Author(s):  
Tanya Wen ◽  
Daniel J Mitchell ◽  
John Duncan
Keyword(s):  
Default Mode Network ◽  
Medial Temporal Lobe ◽  
Activity Patterns ◽  
Univariate Analysis ◽  
Memory Task ◽  
Moral Dilemmas ◽  
Mental States ◽  
Default Mode ◽  
Functional Convergence ◽  
Wide Range

AbstractThe default mode network (DMN) is engaged in a variety of cognitive settings, including social, semantic, temporal, spatial, and self-related tasks. Andrews-Hanna et al. (2010, 2012) proposed that the DMN consists of three distinct functional-anatomical subsystems – a dorsal medial prefrontal cortex (dMPFC) subsystem that supports social processing and introspection about mental states; a medial temporal lobe (MTL) subsystem that contributes to memory retrieval and construction of mental scenes; and a set of midline core hubs that are involved in processing self-referential information. We examined activity in the DMN subsystems during six different tasks: (1) theory of mind and (2) moral dilemmas (for social cognition), (3) autobiographical memory and (4) spatial navigation (for memory-based construction/simulation), (5) self/other adjective judgement (for self-related cognition), and finally, (6) a rest condition compared to a working memory task. At a broad level, we observed similar whole-brain activity maps for the six contrasts, and some response to every contrast in each of the three subsystems. In more detail, both univariate analysis and multivariate activity patterns showed partial functional separation, much of it in close accord with the proposals of separate dMPFC and MTL subsystems, though with less support for common activity across anterior and posterior regions of a midline core. Integrating social, spatial, self-related, and other aspects of a cognitive situation or episode, multiple components of the DMN may work closely together to provide the broad context for current mental activity.Significance StatementActivity in the default mode network (DMN) can been found across a wide range of high-level tasks that involve social, semantic, episodic, or self-referential cognition. Given this diversity, an important proposal is that the DMN can be parcellated into subsystems with different cognitive functions. The current experiment employed a wide range of experimental tasks to directly test for functional convergence and heterogeneity between DMN regions. The results support both partial differentiation and integration; working together, distributed DMN regions may assemble the multiple contextual components of a cognitive situation or episode.

scholarly journals What can narratives tell us about the neural bases of human memory?

2020 ◽  
Author(s):  
Hongmi Lee ◽  
Buddhika Bellana ◽  
janice chen
Keyword(s):  
Temporal Lobe ◽  
Neural Activity ◽  
Default Mode Network ◽  
Medial Temporal Lobe ◽  
Activity Patterns ◽  
Human Memory ◽  
Memory System ◽  
Situation Models ◽  
Neural Synchrony ◽  
Default Mode

Narratives are increasingly used to study naturalistic human memory and its brain mechanisms. Narratives—audiovisual movies, spoken stories, and written stories—consist of multiple inter-related and temporally unfolding events which are rich in semantic and emotional content. These characteristics drive intersubject neural synchrony in the default mode network, where abstract situation models are represented and reinstated. Medial temporal lobe structures interact with the cortical sub-regions of the default mode network to support the encoding and recall of narrative events. Narrative memories are frequently communicated across individuals, resulting in the transmission of experiences and neural activity patterns between people. Recent advances in neuroimaging and naturalistic stimulus analysis provide valuable insights into narrative memory and the human memory system in general.

scholarly journals The dorsal and ventral default mode networks are dissociably modulated by the valence and vividness of imagined events

2020 ◽  
Author(s):  
Sangil Lee ◽  
Trishala Parthasarathi ◽  
Joseph W. Kable
Keyword(s):  
Neural Networks ◽  
Recent Work ◽  
Strong Evidence ◽  
Default Mode Network ◽  
Medial Temporal Lobe ◽  
Brain Activity ◽  
Psychological Processes ◽  
Default Mode ◽  
Scene Construction ◽  
Future Events

AbstractRecent work has shown that the brain’s default mode network (DMN) is active when people imagine the future. Here we test whether future imagination can be decomposed into two dissociable psychological processes linked to different subcomponents of the DMN. While measuring brain activity with fMRI as subjects imagine future events, we manipulate the vividness of these events to modulate the demands for scene construction, and we manipulate the valence of these events to modulate the demands for evaluation. We found that one subcomponent of the DMN, the ventral DMN or medial temporal lobe subsystem, responds to the vividness but not the valence of imagined events. In contrast, another subcomponent, the dorsal or core DMN, responds to the valence but not the vividness of imagined events. This separate modifiability of different subcomponents of the DMN by vividness and valence provides strong evidence for a neurocognitive dissociation between (1) the construction of novel, imagined scenes from individual components from memory and (2) the evaluation of these constructed events as desirable or undesirable.Significance StatementPrevious work has suggested that imagination may depend on separate neural networks involved in the construction and evaluation of imagined future events. This study provides strong neural evidence for this dissociation by demonstrating that two components of the brain’s default mode network (DMN) uniquely and specifically respond to different aspects of imagination. The vividness of imagined events modulates the ventral DMN, but not the dorsal DMN, while the valence of imagined events modulates the dorsal DMN, but not the ventral DMN. This supports the dissociable engagement of these sub-networks in constructing and evaluating imagined future events.

Patterns of Brain Activity Supporting Autobiographical Memory, Prospection, and Theory of Mind, and Their Relationship to the Default Mode Network

2010 ◽  
Vol 22 (6) ◽  
pp. 1112-1123 ◽  
Author(s):  
R. Nathan Spreng ◽  
Cheryl L. Grady
Keyword(s):  
Theory Of Mind ◽  
Default Mode Network ◽  
Brain Activity ◽  
Brain Structures ◽  
Neural Activation ◽  
Default Mode ◽  
Cognitive Behaviors ◽  
Core Set ◽  
Multiple Processes ◽  
Human Feature

The ability to rise above the present environment and reflect upon the past, the future, and the minds of others is a fundamentally defining human feature. It has been proposed that these three self-referential processes involve a highly interconnected core set of brain structures known as the default mode network (DMN). The DMN appears to be active when individuals are engaged in stimulus-independent thought. This network is a likely candidate for supporting multiple processes, but this idea has not been tested directly. We used fMRI to examine brain activity during autobiographical remembering, prospection, and theory-of-mind reasoning. Using multivariate analyses, we found a common pattern of neural activation underlying all three processes in the DMN. In addition, autobiographical remembering and prospection engaged midline DMN structures to a greater degree and theory-of-mind reasoning engaged lateral DMN areas. A functional connectivity analysis revealed that activity of a critical node in the DMN, medial prefrontal cortex, was correlated with activity in other regions in the DMN during all three tasks. We conclude that the DMN supports common aspects of these cognitive behaviors involved in simulating an internalized experience.

scholarly journals Spontaneous Brain Activity in the Default Mode Network Is Sensitive to Different Resting-State Conditions with Limited Cognitive Load

PLoS ONE ◽  
2009 ◽  
Vol 4 (5) ◽  
pp. e5743 ◽  
Author(s):  
Chaogan Yan ◽  
Dongqiang Liu ◽  
Yong He ◽  
Qihong Zou ◽  
Chaozhe Zhu ◽  
...  
Keyword(s):  
Cognitive Load ◽  
Default Mode Network ◽  
Resting State ◽  
Brain Activity ◽  
Default Mode ◽  
Spontaneous Brain Activity

scholarly journals Temporal circuit of macroscale dynamic brain activity supports human consciousness

2020 ◽  
Vol 6 (11) ◽  
pp. eaaz0087 ◽  
Author(s):  
Zirui Huang ◽  
Jun Zhang ◽  
Jinsong Wu ◽  
George A. Mashour ◽  
Anthony G. Hudetz
Keyword(s):  
Default Mode Network ◽  
Functional Role ◽  
Brain Activity ◽  
Human Consciousness ◽  
Attention Network ◽  
Attention Networks ◽  
Default Mode ◽  
Dorsal Attention Network ◽  
Brain States

The ongoing stream of human consciousness relies on two distinct cortical systems, the default mode network and the dorsal attention network, which alternate their activity in an anticorrelated manner. We examined how the two systems are regulated in the conscious brain and how they are disrupted when consciousness is diminished. We provide evidence for a “temporal circuit” characterized by a set of trajectories along which dynamic brain activity occurs. We demonstrate that the transitions between default mode and dorsal attention networks are embedded in this temporal circuit, in which a balanced reciprocal accessibility of brain states is characteristic of consciousness. Conversely, isolation of the default mode and dorsal attention networks from the temporal circuit is associated with unresponsiveness of diverse etiologies. These findings advance the foundational understanding of the functional role of anticorrelated systems in consciousness.

scholarly journals Relationships between default-mode network connectivity, medial temporal lobe structure, and age-related memory deficits

2015 ◽  
Vol 36 (1) ◽  
pp. 265-272 ◽  
Author(s):  
Andrew M. Ward ◽  
Elizabeth C. Mormino ◽  
Willem Huijbers ◽  
Aaron P. Schultz ◽  
Trey Hedden ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Default Mode Network ◽  
Medial Temporal Lobe ◽  
Network Connectivity ◽  
Memory Deficits ◽  
Default Mode ◽  
Age Related
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