Resting-state hyperconnectivity within the default mode network impedes the ability to initiate cognitive performance in first-episode schizophrenia patients

Krukow, Paweł; Jonak, Kamil; Grochowski, Cezary; Plechawska–Wójcik, Małgorzata; Karakuła-Juchnowicz, Hanna

doi:10.1016/j.pnpbp.2020.109959

Cited by 24 publications

(26 citation statements)

References 73 publications

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“…Findings concerning delta band during resting-state in the early phases of schizophrenia are controversial, with some studies reporting no abnormality in delta power ( 73 ) or synchrony ( 74 ), while others finding differences between these subjects and HCs in power ( 75 – 79 ) or functional connectivity ( 80 ) within this band activity.…”

Section: Resultsmentioning

confidence: 99%

EEG-Based Measures in At-Risk Mental State and Early Stages of Schizophrenia: A Systematic Review

et al. 2021

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Introduction: Electrophysiological (EEG) abnormalities in subjects with schizophrenia have been largely reported. In the last decades, research has shifted to the identification of electrophysiological alterations in the prodromal and early phases of the disorder, focusing on the prediction of clinical and functional outcome. The identification of neuronal aberrations in subjects with a first episode of psychosis (FEP) and in those at ultra high-risk (UHR) or clinical high-risk (CHR) to develop a psychosis is crucial to implement adequate interventions, reduce the rate of transition to psychosis, as well as the risk of irreversible functioning impairment. The aim of the review is to provide an up-to-date synthesis of the electrophysiological findings in the at-risk mental state and early stages of schizophrenia.Methods: A systematic review of English articles using Pubmed, Scopus, and PsychINFO was undertaken in July 2020. Additional studies were identified by hand-search. Electrophysiological studies that included at least one group of FEP or subjects at risk to develop psychosis, compared to healthy controls (HCs), were considered. The heterogeneity of the studies prevented a quantitative synthesis.Results: Out of 319 records screened, 133 studies were included in a final qualitative synthesis. Included studies were mainly carried out using frequency analysis, microstates and event-related potentials. The most common findings included an increase in delta and gamma power, an impairment in sensory gating assessed through P50 and N100 and a reduction of Mismatch Negativity and P300 amplitude in at-risk mental state and early stages of schizophrenia. Progressive changes in some of these electrophysiological measures were associated with transition to psychosis and disease course. Heterogeneous data have been reported for indices evaluating synchrony, connectivity, and evoked-responses in different frequency bands.Conclusions: Multiple EEG-indices were altered during at-risk mental state and early stages of schizophrenia, supporting the hypothesis that cerebral network dysfunctions appear already before the onset of the disorder. Some of these alterations demonstrated association with transition to psychosis or poor functional outcome. However, heterogeneity in subjects' inclusion criteria, clinical measures and electrophysiological methods prevents drawing solid conclusions. Large prospective studies are needed to consolidate findings concerning electrophysiological markers of clinical and functional outcome.

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Section: Resultsmentioning

confidence: 99%

EEG-Based Measures in At-Risk Mental State and Early Stages of Schizophrenia: A Systematic Review

et al. 2021

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“…From previous studies, hyperconnectivity in the default mode network has been associated with cognitive impairment (Whitfield-Gabrieli et al, 2009; Yasuda et al, 2013), as well as the deposition of beta-amyloid (Buckner et al, 2005) (116), a marker of Alzheimer disease. Interestingly, individuals with schizophrenia present brain functional hyperconnectivity associated with cognitive impairment in different domains (Krukow, Jonak, Grochowski, Plechawska-Wojcik, & Karakula-Juchnowicz, 2020; Whitfield-Gabrieli et al, 2009). We have previously associated impaired deactivations of the DMN with poor performance on verbal fluency task, in individuals using topiramate (an anti-seizure medication, also used for migraine prophylaxis)(Yasuda et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Functional and microstructural brain abnormalities, fatigue, and cognitive dysfunction after mild COVID-19

Nogueira

et al. 2021

Preprint

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Although post-acute cognitive dysfunction and neuroimaging abnormalities have been reported after hospital discharge in patients recovered from COVID-19, little is known about persistent, long-term alterations in people without hospitalization. We conducted a cross-sectional study of 87 non-hospitalized recovered individuals 54 days after the laboratory confirmation of COVID-19. We performed structured interviews, neurological examination, 3T-MRI scans with diffusion tensor images (DTI) and functional resting-state images (fMRI). Also, we investigated fatigue, anxiety, depression, somnolence, language, memory, and cognitive flexibility, using validated instruments. Individuals self-reported a high frequency of headache (40%) and memory difficulties (33%). The quantitative analyses confirmed symptoms of fatigue (68%), excessive somnolence (35%), anxiety (29%), impaired cognitive flexibility (40%) and language impairment (33%). There were widespread cerebral white matter alterations (mainly characterized by increased fractional anisotropy), which correlated with abnormal attention and cognitive flexibility. The resting-state fMRI networks analysis showed severely disrupted brain hyperconnectivity and loss of resting-state networks specificity.

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“…The eLORETA algorithm allows for the analysis of EEG signals with zero localization error under noise-free conditions. These properties are ensured primarily by the analysis being done on a discrete three-dimensionally distributed linear inverse solution of the EEG signal; hence, the images obtained represent the current density and present the point of exact source localization [ 29 , 32 ]. Nevertheless, the spatial resolution of the results was still low due to the highly correlated neuronal sources that underlie the EEG signals, but the volume conduction errors were removed from the analysis.…”

Section: Methodsmentioning

confidence: 99%

“…Finally, estimated current densities were presented on the eLORETA images as the exact magnitude of the electric activity of each voxel in the Montreal Neurological Institute (MNI) space. Additionally, the current source density analysis was performed for five frequency bands: delta (1–4 Hz), theta (4–8 Hz), alpha (4–12 Hz), beta (13–30 Hz), and gamma (30–45 Hz) [ 32 ].…”

Section: Methodsmentioning

confidence: 99%

Widespread Reductions of Spontaneous Neurophysiological Activity in Leber’s Disease—An Application of EEG Source Current Density Reconstruction

Jonak

2020

Brain Sciences

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Leber’s hereditary optic neuropathy (LHON) is a rare, maternally inherited genetic disease caused by a mutation of mitochondrial DNA. Classical descriptions have highlighted structural abnormalities in various parts of patients’ optic tracts; however, current studies have proved that changes also affect many cortical and subcortical structures, not only these belonging to the visual system. This study aimed at improving our understanding of neurophysiological impairments in LHON. First of all, we wanted to know if there were any differences between the health control and LHON subjects in the whole-brain source electroencephalography (EEG) analysis. Second, we wanted to investigate the associations between the observed results and some selected aspects of Leber’s disease’s clinical picture. To meet these goals, 20 LHON patients and 20 age-matched healthy control (HC) subjects were examined. To investigate the electrophysiological differences between the HC and LHON groups, a quantitative analysis of the whole-brain current source density was performed. The signal analysis method was based on scalp EEG data and an inverse solution method called low-resolution brain electromagnetic tomography (eLORETA). In comparison with the healthy subjects, LHON participants showed significantly decreased neuronal activity in the alpha and gamma bands; more specifically, in the alpha band, the decrease was mainly found in the occipital lobes and secondary visual cortex, whereas, in the gamma band, the reduced activity occurred in multiple cortical areas. Additionally, a correlation was found between the alpha band activity of the right secondary visual cortex and the averaged thickness of the right retinal nerve fiber layer in the LHON participants. Our study suggests that LHON is associated with widespread cortical de-activation, rather than simply abnormalities of structures constituting the visual system.

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Resting-state hyperconnectivity within the default mode network impedes the ability to initiate cognitive performance in first-episode schizophrenia patients

Cited by 24 publications

References 73 publications

EEG-Based Measures in At-Risk Mental State and Early Stages of Schizophrenia: A Systematic Review

EEG-Based Measures in At-Risk Mental State and Early Stages of Schizophrenia: A Systematic Review

Functional and microstructural brain abnormalities, fatigue, and cognitive dysfunction after mild COVID-19

Widespread Reductions of Spontaneous Neurophysiological Activity in Leber’s Disease—An Application of EEG Source Current Density Reconstruction

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