Brain Activity Mapping in Mecp2 Mutant Mice Reveals Functional Deficits in Forebrain Circuits, Including Key Nodes in the Default Mode Network, that are Reversed with Ketamine Treatment

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.

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

PLoS ONE ◽

10.1371/journal.pone.0005743 ◽

2009 ◽

Vol 4 (5) ◽

pp. e5743 ◽

Cited By ~ 212

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

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Temporal circuit of macroscale dynamic brain activity supports human consciousness

Science Advances ◽

10.1126/sciadv.aaz0087 ◽

2020 ◽

Vol 6 (11) ◽

pp. eaaz0087 ◽

Cited By ~ 11

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.

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

Cerebral Cortex ◽

10.1093/cercor/bhaa166 ◽

2020 ◽

Vol 30 (11) ◽

pp. 5915-5929 ◽

Cited By ~ 1

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.

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Reduced resting-state brain activity in the default mode network in children with (central) auditory processing disorders

Behavioral and Brain Functions ◽

10.1186/1744-9081-10-33 ◽

2014 ◽

Vol 10 (1) ◽

pp. 33 ◽

Cited By ~ 6

Author(s):

Agnieszka Pluta ◽

Tomasz Wolak ◽

Natalia Czajka ◽

Monika Lewandowska ◽

Katarzyna Cieśla ◽

...

Keyword(s):

Default Mode Network ◽

Resting State ◽

Auditory Processing ◽

Brain Activity ◽

Central Auditory Processing ◽

Auditory Processing Disorders ◽

Central Auditory Processing Disorders ◽

Default Mode

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Neural markers of negative symptom outcomes in distributed working memory brain activity of antipsychotic-naive schizophrenia patients

The International Journal of Neuropsychopharmacology ◽

10.1017/s1461145712001253 ◽

2013 ◽

Vol 16 (6) ◽

pp. 1195-1204 ◽

Cited By ~ 22

Author(s):

Ayna B. Nejad ◽

Kristoffer H. Madsen ◽

Bjørn H. Ebdrup ◽

Hartwig R. Siebner ◽

Hans Rasmussen ◽

...

Keyword(s):

Working Memory ◽

Negative Symptom ◽

Default Mode Network ◽

Classification Accuracy ◽

Negative Symptoms ◽

Brain Activity ◽

First Episode ◽

Support Vector ◽

Symptom Improvement ◽

Default Mode

Abstract Since working memory deficits in schizophrenia have been linked to negative symptoms, we tested whether features of the one could predict the treatment outcome in the other. Specifically, we hypothesized that working memory-related functional connectivity at pre-treatment can predict improvement of negative symptoms in antipsychotic-treated patients. Fourteen antipsychotic-naive patients with first-episode schizophrenia were clinically assessed before and after 7 months of quetiapine monotherapy. At baseline, patients underwent functional magnetic resonance imaging while performing a verbal n-back task. Spatial independent component analysis identified task-modulated brain networks. A linear support vector machine was trained with these components to discriminate six patients who showed improvement in negative symptoms from eight non-improvers. Classification accuracy and significance was estimated by leave-one-out cross-validation and permutation tests, respectively. Two frontoparietal and one default mode network components predicted negative symptom improvement with a classification accuracy of 79% (p = 0.003). Discriminating features were found in the frontoparietal networks but not the default mode network. These preliminary data suggest that functional patterns at baseline can predict negative symptom treatment–response in schizophrenia. This information may be used to stratify patients into subgroups thereby facilitating personalized treatment.

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Abnormal Spontaneous Brain Activity and Functional Connectivity of the Default Mode Network in Patients with Bipolar Disorder

10.21203/rs.3.rs-194210/v1 ◽

2021 ◽

Author(s):

Lei Zhao ◽

Qijing Bo ◽

Zhifang Zhang ◽

Feng Li ◽

Yuan Zhou ◽

...

Keyword(s):

Bipolar Disorder ◽

Functional Connectivity ◽

Default Mode Network ◽

Resting State ◽

Brain Activity ◽

Seed Region ◽

Potential Candidate ◽

Neural Basis ◽

Default Mode ◽

Spontaneous Brain Activity

Abstract Background: No consistent evidence on the specific brain regions is available in the default mode network (DMN), which show abnormal spontaneous activity in bipolar disorder (BD). We aim to identify this region that is particularly impaired in patients with BD by using several different indices measuring spontaneous brain activity and then investigate its functional connectivity (FC).Methods: A total of 56 patients with BD and 71 healthy controls (HC) underwent resting-state functional magnetic resonance imaging. Three commonly used functional indices were used to identify the brain region showing abnormal spontaneous brain activity in BD. Then, this region served as the seed region for resting-state FC analysis to identify its functional networks altered in BD.Results: The BD group exhibited decreased fALFF, ReHo, and DC values in the left precuneus. The BD group had decreased rsFC within the DMN, indicated by decreased resting-state FC within the left precuneus and between the left precuneus and the medial prefrontal cortex. The BD group had decreased negative connectivity between the left precuneus and the left putamen, extending to the left insula.Conclusions: The findings provide convergent evidence for the abnormalities in the DMN of BD, particularly located in the left precuneus. Decreased FC within the DMN and the disruptive anticorrelation between the DMN and the salience network are found in BD. These findings suggest that the DMN is a key aspect for understanding the neural basis of BD, and the altered functional patterns of DMN may be a potential candidate biomarker of BD.

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Default-Mode Activity during a Passive Sensory Task: Uncoupled from Deactivation but Impacting Activation

Journal of Cognitive Neuroscience ◽

10.1162/0898929042568532 ◽

2004 ◽

Vol 16 (9) ◽

pp. 1484-1492 ◽

Cited By ~ 466

Author(s):

Michael D. Greicius ◽

Vinod Menon

Keyword(s):

Episodic Memory ◽

Cognitive Processing ◽

Neural Activity ◽

Default Mode Network ◽

Brain Activity ◽

Block Design ◽

Brain Regions ◽

Posterior Cingulate Cortex ◽

High Demand ◽

Default Mode

Deactivation refers to increased neural activity during low-demand tasks or rest compared with high-demand tasks. Several groups have reported that a particular set of brain regions, including the posterior cingulate cortex and the medial prefrontal cortex, among others, is consistently deactivated. Taken together, these typically deactivated brain regions appear to constitute a default-mode network of brain activity that predominates in the absence of a demanding external task. Examining a passive, block-design sensory task with a standard deactivation analysis (rest epochs vs. stimulus epochs), we demonstrate that the default-mode network is undetectable in one run and only partially detectable in a second run. Using independent component analysis, however, we were able to detect the full default-mode network in both runs and to demonstrate that, in the majority of subjects, it persisted across both rest and stimulus epochs, uncoupled from the task waveform, and so mostly undetectable as deactivation. We also replicate an earlier finding that the default-mode network includes the hippocampus suggesting that episodic memory is incorporated in default-mode cognitive processing. Furthermore, we show that the more a subject's default-mode activity was correlated with the rest epochs (and “deactivated” during stimulus epochs), the greater that subject's activation to the visual and auditory stimuli. We conclude that activity in the default-mode network may persist through both experimental and rest epochs if the experiment is not sufficiently challenging. Time-series analysis of default-mode activity provides a measure of the degree to which a task engages a subject and whether it is sufficient to interrupt the processes—presumably cognitive, internally generated, and involving episodic memory—mediated by the default-mode network.

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Effect of Acupuncture ‘dose— on Modulation of the Default Mode Network of the Brain

Acupuncture in Medicine ◽

10.1136/acupmed-2016-011071 ◽

2016 ◽

Vol 34 (6) ◽

pp. 425-432 ◽

Cited By ~ 13

Author(s):

Yii-Jeng Lin ◽

Yen-Ying Kung ◽

Wen-Jui Kuo ◽

David M Niddam ◽

Chih-Che Chou ◽

...

Keyword(s):

Default Mode Network ◽

Brain Activity ◽

Resting State Fmri ◽

Default Mode ◽

Left Hand ◽

Conventional Methods ◽

The Right ◽

Active Controls ◽

Increased Activity ◽

Needle Acupuncture

Objective Recent functional MRI (fMRI) studies show that brain activity, including the default mode network (DMN), can be modulated by acupuncture. Conventional means to enhance the neurophysiological ‘dose’ of acupuncture, including an increased number of needles and manual needle manipulation, are expected to enhance its physiological effects. The aim of this study was to compare the effects of both methods on brain activity. Methods 58 healthy volunteers were randomly assigned into four groups that received single needle acupuncture (SNA, n=15) or transcutaneous electrical nerve stimulation (TENS, n=13) as active controls, or enhanced acupuncture by way of three needle acupuncture (TNA, n=17) or SNA plus manual stimulation (SNA+MS, n=13). Treatment-associated sensations were evaluated using a visual analogue scale. Central responses were recorded before, during, and after treatment at LI4 on the left hand using resting state fMRI. Results TNA and SNA+MS induced DMN-insula activity and extensive DMN activity compared to SNA, despite comparable levels of de qi sensation. The TNA and SNA+MS groups exhibited a delayed and enhanced modulation of the DMN, which was not observed followed SNA and TENS. Furthermore, TNA increased precuneus activity and increased the DMN-related activity of the cuneus and left insula, while SNA+MS increased activity in the right insula. Conclusions The results showed that conventional methods to enhance the acupuncture dose induce different DMN modulatory effects. TNA induces the most extensive DMN modulation, compared with other methods. Conventional methods of enhancing the acupuncture dose could potentially be applied as a means of modulating brain activity.

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