Coexistence of the Social Semantic Effect and Non-Semantic Effect in the Default Mode Network

Abstract Neuroimaging studies have found both semantic and non-semantic effects in the default mode network (DMN), leading to an intense debate on the role of the DMN in semantic processes. Four different views have been proposed: 1) The general semantic view holds that the DMN contains several hub regions supporting general semantic processes; 2) the non-semantic view holds that the semantic effects observed in most regions of the DMN (especially the ventral angular gyrus) are confounded by difficulty and do not reflect semantic processing per se; 3) the multifunction view holds that the same areas in the DMN can support both semantic and non-semantic functions; and 4) the multisystem view holds that the DMN contains multiple subnetworks supporting different aspects of semantic processes separately. Using an fMRI experiment, we found that in one of the subnetworks of the DMN, called the social semantic network, all areas showed social semantic activation and difficulty-induced deactivation. The ventral angular gyrus, whose function had been interpreted according to the difficulty effect, showed social semantic activation independent of difficulty. In addition, the distributions of two non-semantic effects, that is, difficulty-induced and task-induced deactivations, showed dissociation in the DMN. Our findings provide two insights into the semantic and non-semantic functions of the DMN, which are consistent with both the multisystem and multifunction views: First, the same areas of the DMN can support both social semantic and non-semantic functions; second, similar to the multiple semantic effects of the DMN, the non-semantic effects also vary across its subsystems.

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Temporoparietal Connectivity Within Default Mode Network Associates With Clinical Improvements in Schizophrenia Following Modified Electroconvulsive Therapy

Frontiers in Psychiatry ◽

10.3389/fpsyt.2021.768279 ◽

2022 ◽

Vol 12 ◽

Author(s):

Qiang Hu ◽

Huan Huang ◽

Yuchao Jiang ◽

Xiong Jiao ◽

Jie Zhou ◽

...

Keyword(s):

Electroconvulsive Therapy ◽

Default Mode Network ◽

Angular Gyrus ◽

Middle Temporal Gyrus ◽

Default Mode ◽

Before And After ◽

Mental Symptoms ◽

Mri Scans ◽

Modified Electroconvulsive Therapy ◽

The Right

Although modified electroconvulsive therapy (ECT) has been reported to be effective for the treatment of schizophrenia (SCZ), its action mechanism is unclear. To elucidate the underlying ECT mechanisms of SCZ, this study used a longitudinal cohort including 21 SCZ patients receiving only antipsychotics (DSZ group) and 21 SCZ patients receiving a regular course of ECT combining with antipsychotics (MSZ group) for 4 weeks. All patients underwent magnetic resonance imaging (MRI) scans at baseline (t1) and follow-up (t2) time points. A matched healthy control (HC) group included 23 individuals who were only scanned at baseline. Functional connectivity (FC) within the default mode network (DMN) was evaluated before and after ECT. Significant interaction of the group over time was found in FC between angular gyrus (AG) and middle temporal gyrus (MTG). Post-hoc analysis showed a significantly enhanced FC of left AG(AG.L) and right MTG (MTG.R) in the MSZ group relative to the DSZ group. In addition, the right AG (AG.R) showed significantly enhanced FC between MTG.R and left MTG (MTG.L) after ECT in the MSZ group, but no in the DSZ group. In particular, the FCs change in AG.L-MTG.R and AG.R-MTG.R were positively correlated with the Positive and Negative Syndrome Scale (PANSS) negative score reduction. Furthermore, the FC change in AG.L-MTG.R was also positively correlated with the PANSS general psychopathology score reduction. These findings confirmed a potential relationship between ECT inducing hyperconnectivity within DMN and improvements in symptomatology of SCZ, suggesting that ECT controls mental symptoms by regulating the temporoparietal connectivity within DMN.

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Examining resting-state functional connectivity in key hubs of the default mode network in chronic low back pain

Scandinavian Journal of Pain ◽

10.1515/sjpain-2020-0184 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Sin Ki Ng ◽

Donna M. Urquhart ◽

Paul B. Fitzgerald ◽

Flavia M. Cicuttini ◽

Melissa Kirkovski ◽

...

Keyword(s):

Low Back Pain ◽

Back Pain ◽

Functional Connectivity ◽

Default Mode Network ◽

Chronic Low Back Pain ◽

Resting State ◽

Angular Gyrus ◽

Healthy Controls ◽

Low Back ◽

Default Mode

Abstract Objectives Changes in brain connectivity have been observed within the default mode network (DMN) in chronic low back pain (CLBP), however the extent of these disruptions and how they may be related to CLBP requires further examination. While studies using seed-based analysis have found disrupted functional connectivity in the medial prefrontal cortex (mPFC), a major hub of the DMN, limited studies have investigated other equally important hubs, such as the posterior cingulate cortex (PCC) in CLBP. Methods This preliminary study comprised 12 individuals with CLBP and 12 healthy controls who completed a resting-state functional magnetic resonance imaging (fMRI) scan. The mPFC and PCC were used as seeds to assess functional connectivity. Results Both groups displayed similar patterns of DMN connectivity, however group comparisons showed that CLBP group had reduced connectivity between the PCC and angular gyrus compared to healthy controls. An exploratory analysis examined whether the alterations observed in mPFC and PCC connectivity were related to pain catastrophizing in CLBP, but no significant associations were observed. Conclusions These results may suggest alterations in the PCC are apparent in CLBP, however, the impact and functional role of these disruptions require further investigation.

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Aberrant topographical organization in default-mode network in first-episode remitted geriatric depression: a graph-theoretical analysis

International Psychogeriatrics ◽

10.1017/s1041610218000054 ◽

2018 ◽

Vol 30 (5) ◽

pp. 619-628 ◽

Cited By ~ 3

Author(s):

Yan Zhu ◽

Dongqing Wang ◽

Zhe Liu ◽

Yuefeng Li

Keyword(s):

Default Mode Network ◽

Resting State ◽

Pearson Correlation ◽

Angular Gyrus ◽

Middle Temporal Gyrus ◽

First Episode ◽

Healthy Controls ◽

Geriatric Depression ◽

Default Mode ◽

Topological Organization

ABSTRACTBackground:Neuroimaging studies have shown that major depressive disorder is associated with altered activity patterns of the default-mode network (DMN). In this study, we sought to investigate the topological organization of the DMN in patients with remitted geriatric depression (RGD) and whether RGD patients would be more likely to show disrupted topological configuration of the DMN during the resting-state.Methods:Thirty-three RGD patients and thirty-one healthy control participants underwent clinical and cognitive evaluations as well as resting-state functional magnetic resonance imaging scans. The functional connectivity (FC) networks were constructed by thresholding Pearson correlation metrics of the DMN regions defined by group independent component analysis, and their topological properties (e.g. small-world and network efficiency) were analyzed using graph theory-based approaches.Results:Relative to the healthy controls, the RGD patients showed decreased FC in the posterior regions of the DMN (i.e. the posterior cingulate cortex/precuneus, angular gyrus, and middle temporal gyrus). Furthermore, the RGD patients showed abnormal global topology of the DMN (i.e. increased characteristic path length and reduced global efficiency) when compared with healthy controls. Importantly, significant correlations between these network measures and cognitive performance indicated their potential use as biomarkers of cognitive dysfunction in RGD.Conclusions:The present study indicated disrupted FC and topological organization of the DMN in the context of RGD, and further implied their contribution to cognitive deficits in RGD patients.

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Resting-state Modulation of Alpha Rhythms by Interference with Angular Gyrus Activity

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00460 ◽

2014 ◽

Vol 26 (1) ◽

pp. 107-119 ◽

Cited By ~ 26

Author(s):

Paolo Capotosto ◽

Claudio Babiloni ◽

Gian Luca Romani ◽

Maurizio Corbetta

Keyword(s):

Default Mode Network ◽

Resting State ◽

Low Frequency ◽

Angular Gyrus ◽

Alpha Power ◽

Default Mode ◽

Dorsal Attention Network ◽

Left And Right ◽

Eeg Alpha ◽

Adult Volunteers

The default mode network is active during restful wakefulness and suppressed during goal-driven behavior. We hypothesize that inhibitory interference with spontaneous ongoing, that is, not task-driven, activity in the angular gyrus (AG), one of the core regions of the default mode network, will enhance the dominant idling EEG alpha rhythms observed in the resting state. Fifteen right-handed healthy adult volunteers underwent to this study. Compared with sham stimulation, magnetic stimulation (1 Hz for 1 min) over both left and right AG, but not over FEF or intraparietal sulcus, core regions of the dorsal attention network, enhanced the dominant alpha power density (8–10 Hz) in occipitoparietal cortex. Furthermore, right AG-rTMS enhanced intrahemispheric alpha coherence (8–10 Hz). These results suggest that AG plays a causal role in the modulation of dominant low-frequency alpha rhythms in the resting-state condition.

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Shared understanding is correlated with shared neural responses in the default mode network

10.1101/231019 ◽

2017 ◽

Cited By ~ 1

Author(s):

Mai Nguyen ◽

Tamara Vanderwal ◽

Uri Hasson

Keyword(s):

Individual Differences ◽

Default Mode Network ◽

Neural Responses ◽

Default Mode ◽

Fmri Study ◽

Abstract Shape ◽

The Social ◽

Original Animation ◽

Narrative Interpretation ◽

The Brain

AbstractHumans have a striking ability to infer meaning from even the sparsest and most abstract forms of narratives. At the same time, flexibility in the form of a narrative is matched by inherent ambiguity in the interpretation of it. How does the brain represent subtle, idiosyncratic differences in the interpretation of abstract and ambiguous narratives? In this fMRI study, we scanned subjects watching a 7-min original animation that depicts a complex narrative through the movement of simple geometric shapes. We additionally scanned two separate groups listening to concrete verbal descriptions of either the social narrative or the physical properties of the movie. After scanning, all subjects freely recalled their interpretation of the stimulus. Using an intersubject representational similarity analysis, we compared the similarity of narrative interpretation across subjects, as measured using text analysis, with the similarity of neural responses, as measured using intersubject correlation (ISC). We found that the more similar two people’s interpretations of the abstract shape movie were, the more similar their neural responses were in the default mode network (DMN). Moreover, these shared responses were modality invariant: despite vast differences in stimulus properties, we found that the shapes movie and the verbal interpretation of the movie elicited shared responses in linguistic areas and a subset of the DMN when subjects shared interpretations. Together, these results suggest that the DMN is not only sensitive to subtle individual differences in narrative interpretation, but also resilient to large differences in the modality of the narrative.Significance statementThe same narrative can be both communicated in different ways and interpreted in different ways. How are subtle, idiosyncratic differences in the interpretation of complex narratives presented in different forms represented in the brain? In this fMRI study, we show that the more similarly two people interpreted an ambiguous animation composed of moving shapes, the more similar their neural responses were in the Default Mode Network. In addition, by presenting the same narrative in a different form, we found shared responses across modalities when subjects shared interpretations despite the vast differences in modality of the stimuli. Together, these results suggest that the DMN is at once sensitive to individual differences in narrative interpretation and resilient to differences narrative modality.

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The ‘social default mode network’ mediates the impact of infant regulatory problems on adult social-emotional problems

10.26226/morressier.5b31ec2c2afeeb001345a4ee ◽

2018 ◽

Author(s):

Josef G. Bäuml

Keyword(s):

Default Mode Network ◽

Emotional Problems ◽

Social Emotional ◽

Default Mode ◽

The Social ◽

The Impact ◽

Regulatory Problems

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Default Mode Network Disruption in Stroke-Free Patients with Atrial Fibrillation

Cerebrovascular Diseases ◽

10.1159/000486689 ◽

2018 ◽

Vol 45 (1-2) ◽

pp. 78-84 ◽

Cited By ~ 3

Author(s):

Danilo S. Silva ◽

Wagner M. Avelar ◽

Brunno M. de Campos ◽

Ana Paula B.L. Lino ◽

Márcio L.F. Balthazar ◽

...

Keyword(s):

Atrial Fibrillation ◽

Default Mode Network ◽

Brain Networks ◽

Anterior Cingulate ◽

Angular Gyrus ◽

Default Mode ◽

Eyes Closed ◽

Dementia Patients ◽

Left Angular Gyrus ◽

Level Analysis

Background: Atrial fibrillation (AF) is a widely accepted risk for causing stroke. However, recent studies show AF as a risk factor for dementia, even without causing stroke. The mechanisms by which dementia develops in stroke-free patients with AF are still poorly understood and the association of AF with abnormal function of brain networks activities, such as the default mode network (DMN), has not been previously studied. We aimed to determine whether, in the absence of stroke and dementia, patients with AF have abnormal resting-state brain networks compared to controls without AF. Methods: Twenty-one stroke-free patients with AF and 21 age- and sex-matched controls without AF underwent brain functional magnetic resonance imaging acquired at a 3.0 Tesla scanner. During the exam, the subjects were instructed to lie still with eyes closed. At first-level analysis, connectivity of the DMN was obtained for all subjects. Second-level analysis compared the DMN connectivity between AF patients and controls with a general linear model (two-sample t test, p < 0.05, False Discovery Rate corrected, minimum of 50 contiguous voxels). Results: Patients with AF compared with controls showed decreased connectivity in regions of the DMN including the frontal lobe (left medial frontal gyrus, left superior frontal gyrus and anterior cingulate), left angular gyrus, and bilateral precuneus. Conclusions: Stroke-free patients with AF have evidence of abnormal DMN connectivity. This study adds evidence to the occurrence of cerebral dysfunction in patients with AF.

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Establishing task- and modality-dependent dissociations between the semantic and default mode networks

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1422760112 ◽

2015 ◽

Vol 112 (25) ◽

pp. 7857-7862 ◽

Cited By ~ 98

Author(s):

Gina F. Humphreys ◽

Paul Hoffman ◽

Maya Visser ◽

Richard J. Binney ◽

Matthew A. Lambon Ralph

Keyword(s):

Task Difficulty ◽

Semantic Network ◽

Semantic Representation ◽

Resting State Fmri ◽

Common Interest ◽

Angular Gyrus ◽

Default Mode ◽

Clinical Biomarkers ◽

Cognitive Coherence ◽

Cortical Regions

The default mode network (DMN) and semantic network (SN) are two of the most extensively studied systems, and both are increasingly used as clinical biomarkers in neurological studies. There are strong theoretical reasons to assume a relationship between the networks, as well as anatomical evidence that they might rely on overlapping cortical regions, such as the anterior temporal lobe (ATL) or angular gyrus (AG). Despite these strong motivations, the relationship between the two systems has received minimal attention. We directly compared the SN and DMN using a large (n = 69) distortion-corrected functional MRI (fMRI) dataset, spanning a range of semantic and nonsemantic tasks that varied input modality. The results showed that both networks fractionate depending on the semantic nature of the task, stimulus type, modality, and task difficulty. Furthermore, despite recent claims that both AG and ATL are semantic hubs, the two areas responded very differently, with results supporting the role of ATL, but not AG, in semantic representation. Specifically, the left ATL was positively activated for all semantic tasks, but deactivated during nonsemantic task performance. In contrast, the left AG was deactivated for all tasks, with the level of deactivation related to task difficulty. Thus, ATL and AG do not share a common interest in semantic tasks, but, rather, a common “disinterest” in nonsemantic tasks. The implications for the variability in the DMN, its cognitive coherence, and interpretation of resting-state fMRI data are discussed.

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