T134. THE ROLE OF THE DEFAULT MODE NETWORK IN SCHIZOPHRENIA AND AUDITORY VERBAL HALLUCINATIONS – AN INVESTIGATION OF DYNAMIC FMRI RESTING STATE CONNECTIVITY

Abstract Background There is a wealth of evidence showing aberrant functional connectivity (FC) in schizophrenia but with considerable variability in findings across studies. Dynamic FC is an extension of traditional static FC, in that such analyses allow for explorations of temporal changes in connectivity. Thereby they also provide more detailed information on connectivity abnormalities in psychiatric disorders such as schizophrenia. Methods The current study investigated dynamic FC in a sample of 80 schizophrenia patients and 80 matched healthy control subjects. Furthermore, relationships with auditory verbal hallucinations (AVH), a core symptom of schizophrenia, were explored. Two measures of AVH were used, one measure of current AVH severity assessed on the day of scanning, and one trait-measure where AVH were assessed repeatedly over the course of one year. Results Compared to healthy controls, schizophrenia patients showed increased dwell times in states with high connectivity within the default mode network (DMN). Current AVH severity did not show a significant relationship with dynamic FC. However, the trait-measure of AVH proneness over one year showed a significant relationship with dynamic FC. Patients with high AVH proneness spent less time in connectivity states characterized by strong anti-correlation between the DMN and task-positive networks. Discussion The results provide further evidence for a DMN dysfunction in schizophrenia, which could be linked to thought disturbances in relation to an increased internal focus of cognitive processing. The effects of AVH proneness on dynamic FC support theoretical models of AVH which have proposed an instability of the DMN and impaired cognitive control in AVH patients. The results also point to AVH proneness as a potential marker for identifying distinct subgroups of schizophrenia patients.

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Aberrant Functional Connectivity Patterns of Default Mode Network May Play a Key Role in the Interaction between Auditory Verbal Hallucinations and Insight

Chinese Medical Journal ◽

10.4103/0366-6999.226905 ◽

2018 ◽

Vol 131 (6) ◽

pp. 736-738 ◽

Cited By ~ 1

Author(s):

Ri-Xing Jing ◽

Shen Li ◽

Xin-Jun Zhang ◽

Jing Long ◽

Tian-Hong Zhou ◽

...

Keyword(s):

Functional Connectivity ◽

Default Mode Network ◽

Default Mode ◽

Auditory Verbal Hallucinations ◽

Connectivity Patterns

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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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Neurofeedback of core language network nodes modulates connectivity with the default-mode network: A double-blind fMRI neurofeedback study on auditory verbal hallucinations

NeuroImage ◽

10.1016/j.neuroimage.2019.01.058 ◽

2019 ◽

Vol 189 ◽

pp. 533-542 ◽

Cited By ~ 15

Author(s):

Jana Zweerings ◽

Bastian Hummel ◽

Micha Keller ◽

Mikhail Zvyagintsev ◽

Frank Schneider ◽

...

Keyword(s):

Default Mode Network ◽

Double Blind ◽

Network Nodes ◽

Default Mode ◽

Auditory Verbal Hallucinations ◽

Core Language ◽

Language Network

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P.1.i.009 Default mode network alterations in refractory schizophrenia patients with auditory verbal hallucinations

European Neuropsychopharmacology ◽

10.1016/s0924-977x(13)70417-6 ◽

2013 ◽

Vol 23 ◽

pp. S267-S268

Author(s):

A. Alonso-Solis ◽

Y. Vives-Gilabert ◽

E.M. Grasa ◽

S. Durán-Sindreu ◽

A. Keymer ◽

...

Keyword(s):

Default Mode Network ◽

Default Mode ◽

Auditory Verbal Hallucinations

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Challenging the notion of a task-negative network: default mode network involvement under varying levels of cognitive effort

10.1101/2021.11.03.466925 ◽

2021 ◽

Author(s):

Sarah Weber ◽

Andre Aleman ◽

Kenneth Hugdahl

Keyword(s):

Cognitive Processing ◽

Default Mode Network ◽

Word Reading ◽

Block Design ◽

Network Connectivity ◽

Cognitive Effort ◽

Attention And Executive Control ◽

Cognitive Demands ◽

Default Mode ◽

High Effort

Everyday cognitive functioning is characterized by constant alternations between different modes of information processing, driven by fluctuations in environmental demands. At the neural level, this is realized through corresponding dynamic shifts in functional activation and network connectivity. A distinction is often made between the Default Mode Network (DMN) as a task-negative network that is upregulated in the absence of cognitive demands, and task-positive networks that are upregulated when cognitive demands such as attention and executive control are present. Such networks have been labelled the Extrinsic Mode Network (EMN). We investigated changes in brain activation and functional network connectivity during repeated alternations between levels of cognitive effort. Using fMRI and a block-design Stroop paradigm, participants switched back and forth between periods of no effort (resting), low effort (word reading, automatic processing) and high effort (color naming, cognitive control). Results showed expected EMN-activation for task versus rest, and likewise expected DMN-activation for rest versus task. The DMN was also more strongly activated during low effort contrasted with high effort, suggesting a gradual up- and down-regulation of the DMN, depending on the level of demand. The often reported anti-correlation between DMN and EMN was only present during periods of low effort, indicating intermittent contributions of both networks. These results challenge the traditional view of the DMN as solely a task-negative network. Instead, the present results suggest that both EMN and DMN may contribute to low-effort cognitive processing. In contrast, periods of resting and high effort are dominated by the DMN and EMN, respectively.

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Increased resting state connectivity in the anterior default mode network of idiopathic epileptic dogs

Scientific Reports ◽

10.1038/s41598-021-03349-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Katrin M. Beckmann ◽

Adriano Wang-Leandro ◽

Henning Richter ◽

Rima N. Bektas ◽

Frank Steffen ◽

...

Keyword(s):

Functional Connectivity ◽

Default Mode Network ◽

Resting State ◽

Large Scale ◽

Group Level ◽

Resting State Networks ◽

Default Mode ◽

Starting Point ◽

Healthy Control ◽

Large Scale Networks

AbstractEpilepsy is one of the most common chronic, neurological diseases in humans and dogs and considered to be a network disease. In human epilepsy altered functional connectivity in different large-scale networks have been identified with functional resting state magnetic resonance imaging. Since large-scale resting state networks have been consistently identified in anesthetised dogs’ application of this technique became promising in canine epilepsy research. The aim of the present study was to investigate differences in large-scale resting state networks in epileptic dogs compared to healthy controls. Our hypothesis was, that large-scale networks differ between epileptic dogs and healthy control dogs. A group of 17 dogs (Border Collies and Greater Swiss Mountain Dogs) with idiopathic epilepsy was compared to 20 healthy control dogs under a standardized sevoflurane anaesthesia protocol. Group level independent component analysis with dimensionality of 20 components, dual regression and two-sample t test were performed and revealed significantly increased functional connectivity in the anterior default mode network of idiopathic epileptic dogs compared to healthy control dogs (p = 0.00060). This group level differences between epileptic dogs and healthy control dogs identified using a rather simple data driven approach could serve as a starting point for more advanced resting state network analysis in epileptic dogs.

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Spectral Diversity in Default Mode Network Connectivity Reflects Behavioral State

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01213 ◽

2018 ◽

Vol 30 (4) ◽

pp. 526-539 ◽

Cited By ~ 9

Author(s):

Michael M. Craig ◽

Anne E. Manktelow ◽

Barbara J. Sahakian ◽

David K. Menon ◽

Emmanuel A. Stamatakis

Keyword(s):

Functional Connectivity ◽

Cognitive Processing ◽

Default Mode Network ◽

Functional Integration ◽

Network Connectivity ◽

Task Execution ◽

Attention Network ◽

High Frequencies ◽

Default Mode ◽

Dorsal Attention Network

Default mode network (DMN) functional connectivity is thought to occur primarily in low frequencies (<0.1 Hz), resulting in most studies removing high frequencies during data preprocessing. In contrast, subtractive task analyses include high frequencies, as these are thought to be task relevant. An emerging line of research explores resting fMRI data at higher-frequency bands, examining the possibility that functional connectivity is a multiband phenomenon. Furthermore, recent studies suggest DMN involvement in cognitive processing; however, without a systematic investigation of DMN connectivity during tasks, its functional contribution to cognition cannot be fully understood. We bridged these concurrent lines of research by examining the contribution of high frequencies in the relationship between DMN and dorsal attention network at rest and during task execution. Our findings revealed that the inclusion of high frequencies alters between network connectivity, resulting in reduced anticorrelation and increased positive connectivity between DMN and dorsal attention network. Critically, increased positive connectivity was observed only during tasks, suggesting an important role for high-frequency fluctuations in functional integration. Moreover, within-DMN connectivity during task execution correlated with RT only when high frequencies were included. These results show that DMN does not simply deactivate during task execution and suggest active recruitment while performing cognitively demanding paradigms.

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