Weak Task Synchronization of Default Mode Network in Task Based Paradigms

Mapping Intimacies ◽

10.1101/2021.04.09.439206 ◽

2021 ◽

Author(s):

Vaibhav Tripathi ◽

Rahul Garg

Keyword(s):

Linear Model ◽

Default Mode Network ◽

Active Component ◽

General Linear Model ◽

General Linear ◽

Negative Behavior ◽

Temporal Synchronization ◽

Default Mode ◽

The Brain

Default Mode Network (DMN) has been called a "task-negative" network which deactivates during engaging extrinsic tasks. But the behavior is more nuanced. We analyse the DMN during three different tasks (visual, affect and language; n=54) and find inter trial variability which gets amiss when analysed using General Linear Model (GLM). The region also shows significant across subjects variations which limits the use of Inter Subject Correlation (ISC) method to detect correlated deactivations during the task. We introduce Temporal Synchronization Analysis (TSA), a family of methods that can help detect inter-trial (IT-TSA) and inter-subject (IS-TSA) synchronization across the brain. We find that DMN is weakly synchronized across trials and subjects, challenging the notion of task negative behavior. Our study suggests the role of DMN as an active component associated with self-referential, autobiographical processes which are deactivated differentially and non linearly across trials and subjects in the presence of extrinsic processes.

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Cortical and subcortical morphology deficits in cerebral gray matter in patients with schizophrenia and not affected siblings

European Psychiatry ◽

10.1016/j.eurpsy.2016.01.632 ◽

2016 ◽

Vol 33 (S1) ◽

pp. s249-s249

Author(s):

F. Pastoriza ◽

L. Galindo ◽

A. Mané ◽

D. Bergé ◽

N. Pujol ◽

...

Keyword(s):

Magnetic Resonance ◽

Linear Model ◽

Cortical Thickness ◽

A Priori ◽

Multiple Comparisons ◽

General Linear Model ◽

General Linear ◽

Group Differences ◽

Competing Interest ◽

The Brain

ObjectiveExplore the basis of cortical morphometry in patients with schizophrenia and non-affected siblings by Magnetic Resonance Structural analyzing cortical thickness.MethodsTwenty-nine patients with schizophrenia treated with atypical antipsychotics and clinically stable in the last 6 months were recruited. Twenty-three not affected siblings of patients with schizophrenia and 37 healthy volunteers were recruited. Magnetic Resonance Structural was performed. FreeSurfer the brain imaging software package for analysis of Cortical Thickness is used. In the analysis of group differences in cortical thickness (CT) with the general linear model (GLM), the P-value was established in 0003 following the Bonferroni correction to control for multiple comparisons (seven regions of interest a priori in each hemisphere).ResultsSignificant differences in cortical thickness between patients and healthy controls. Differences between groups were calculated by general linear model (GLM) with age and sex as covairables (Table 1).ConclusionsIn applying the correction for multiple comparisons, differences in bilateral-lateral orbitofrontal, medial orbitofrontal-right and left temporal transverse frontal cortex are significant. Our study replicates previous findings and provides further evidence of abnormalities in the cerebral cortex, particularly in the frontal and temporal regions, being characteristic of schizophrenia.Disclosure of interestThe authors have not supplied their declaration of competing interest.AcknowledgementsL. Galindo is a Rio-Hortega-fellowship-(ISC-III; CM14/00111).

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The Chief Role of Frontal Operational Module of the Brain Default Mode Network in the Potential Recovery of Consciousness from the Vegetative State: A Preliminary Comparison of Three Case Reports

The Open Neuroimaging Journal ◽

10.2174/1874440001610010041 ◽

2016 ◽

Vol 10 (1) ◽

pp. 41-51 ◽

Cited By ~ 8

Author(s):

Alexander A. Fingelkurts ◽

Andrew A. Fingelkurts ◽

Sergio Bagnato ◽

Cristina Boccagni ◽

Giuseppe Galardi

Keyword(s):

Default Mode Network ◽

Case Reports ◽

Sense Of Self ◽

Vegetative State ◽

Post Injury ◽

Course Of Disease ◽

Default Mode ◽

Person Perspective ◽

The Brain

It has been argued that complex subjective sense of self is linked to the brain default-mode network (DMN). Recent discovery of heterogeneity between distinct subnets (or operational modules - OMs) of the DMN leads to a reconceptualization of its role for the experiential sense of self. Considering the recent proposition that the frontal DMN OM is responsible for the first-person perspective and the sense of agency, while the posterior DMN OMs are linked to the continuity of ‘I’ experience (including autobiographical memories) through embodiment and localization within bodily space, we have tested in this study the hypothesis that heterogeneity in the operational synchrony strength within the frontal DMN OM among patients who are in a vegetative state (VS) could inform about a stable self-consciousness recovery later in the course of disease (up to six years post-injury). Using EEG operational synchrony analysis we have demonstrated that among the three OMs of the DMN only the frontal OM showed important heterogeneity in VS patients as a function of later stable clinical outcome. We also found that the frontal DMN OM was characterized by the process of active uncoupling (stronger in persistent VS) of operations performed by the involved neuronal assemblies.

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Connectivity between the hippocampus and default mode network during the relief, but not elicitation, of curiosity supports curiosity-enhanced memory enhancements

10.1101/2021.07.26.453739 ◽

2021 ◽

Author(s):

Charlotte Murphy ◽

Charan Ranganath ◽

Matthias J Gruber

Keyword(s):

Default Mode Network ◽

Information Seeking ◽

Short Delay ◽

Default Mode ◽

Memory Integration ◽

Subcortical Regions ◽

Cortical Regions ◽

Enhanced Learning ◽

The Brain

Consistent with the idea that curiosity enhances information seeking, it has been shown that activity within both the dopaminergic circuit and hippocampus supports curiosity-enhanced learning. However, the role of whole-brain mechanisms involved in cognitive control (fronto-parietal network; FPN) and memory integration (default mode network; DMN) that might underpin curiosity states and their effects on memory remain elusive. We hypothesised that the FPN and DMN should distinguish between high- and low-curiosity conditions and be recruited more heavily for later remembered information associated with high-curiosity. Here, we used functional magnetic resonance imaging whilst participants completed a trivia paradigm, in which we presented trivia questions associated with high- and low-curiosity, followed by the associated answer. After a short delay, we tested memory for trivia answers. We adopted a network-based parcellation of the brain into subnetworks of the FPN and DMN to examine how neural activity within, and functional connectivity between, each subnetwork predicts curiosity-enhanced memory. Across elicitation and relief of curiosity, we found focal recruitment of FPNA and widespread recruitment of DMN subnetworks in support of curiosity and curiosity-enhanced memory. Most importantly, during the elicitation of curiosity, functional subcortical connectivity and across cortical networks, but not subcortical-cortical coupling, correlated with curiosity-enhanced memory. However, during the relief of curiosity, coupling between subcortical regions and DMNA emerged in support of curiosity-enhanced memory. Taken together, our results provide the first evidence about how neuromodulatory mechanisms via the hippocampal-dopaminergic circuit trigger states of curiosity and thereby communicate to higher-order cortical regions to facilitate curiosity-enhanced memory.

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