Differences of temporal dynamics and signal complexity of gamma band oscillations in first-episode psychosis during a working memory task

Missonnier, Pascal; Curtis, Logos; Ventura, Joseph; Herrmann, Françoís; Merlo, M.C.G.

doi:10.1007/s00702-017-1728-5

Cited by 4 publications

(8 citation statements)

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“…We previously reported neurophysiological disturbances in gamma oscillation patterns in first-episode psychosis patients (Missonnier et al 2017). The present work was designed to further study the nature of these disrupted oscillatory activities in FEP patients.…”

Section: Discussionmentioning

confidence: 99%

“…The present work is based on data collected for a previous study performed in a cohort of healthy controls and firstepisode psychosis patients (Missonnier et al 2012(Missonnier et al , 2017. The protocol was approved by the Ethics Committee of the University Hospitals of Geneva, Switzerland.…”

Section: Participantsmentioning

confidence: 99%

“…The protocol was approved by the Ethics Committee of the University Hospitals of Geneva, Switzerland. Details of data collection and population demographics have been extensively described previously (Missonnier et al 2012(Missonnier et al , 2017.…”

Section: Participantsmentioning

confidence: 99%

“…Patients with other types of drug abuse, as well as with history of sustained head injury or other neurologic or psychiatric disorders, were excluded. The severity of the patients' symptoms was rated using items of the Brief Psychiatric Rating Scale (BPRS) (Ventura et al 1993;Missonnier et al 2012Missonnier et al , 2017.…”

Section: Participantsmentioning

confidence: 99%

“…The protocol also included an attentional active detection task (memory free) and a passive fixation of letter series task (see Fig. 1 and Missonnier et al 2012Missonnier et al , 2017 for thorough description of the experimental procedures). The duration of the experiment was approximately 40 min.…”

Section: Experimental Designmentioning

confidence: 99%

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Disruption of gamma–delta relationship related to working memory deficits in first-episode psychosis

et al. 2019

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Working memory (WM) deficits constitute a core symptom of schizophrenia. Inadequacy of WM maintenance in schizo-phrenia has been reported to reflect abnormalities in the excitation/inhibition (E/I) balance between pyramidal neurons and parvalbumin basket cells, which may explain alterations of the dynamics of gamma and delta oscillations. To address this issue, we assessed event-related gamma (35-45 Hz) and delta (0.5-4 Hz) oscillatory responses in a visual n-back WM task in patients with first-episode psychosis (FEP) and healthy controls (HC). Periodicity analyses of oscillations were computed to explore the relationship between the psychiatric status and the WM load-related processes reflected by each frequency range. The correspondence between nested delta-gamma oscillations was estimated to assess the strength of the frontal E/I balance. In HC, gamma oscillations were synchronized by the stimulus in a 50-150 ms time range for all tasks, and periodicity of the delta cycle was comparable between the tasks. In addition, synchronization of gamma oscillations in HC occurred at the maximal descending phase of the delta cycle half-period, supporting the coexistence of delta-nested gamma oscillations. Compared with controls, FEP patients showed a lack of gamma synchronization independently of the nature of the task, and the period of delta oscillation increased significantly with the difficulty of the WM task. We thus demonstrated in FEP an inability to encode multiple items in short-term memory associated with abnormalities in the relationship between oscillations related to the difficulty of the WM task. These results argue in favor of a dysfunction of the E/I balance in psychosis.

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Section: Discussionmentioning

confidence: 99%

Section: Participantsmentioning

confidence: 99%

Section: Participantsmentioning

confidence: 99%

Section: Participantsmentioning

confidence: 99%

Section: Experimental Designmentioning

confidence: 99%

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Disruption of gamma–delta relationship related to working memory deficits in first-episode psychosis

et al. 2019

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Measurement and Modulation of Working Memory-Related Oscillatory Abnormalities

Kavanaugh

Fryc

Carpenter

2019

J Int Neuropsychol Soc

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Despite the critical role of working memory (WM) in neuropsychiatric conditions, there remains a dearth of available WM-targeted interventions. Gamma and theta oscillations as measured with electroencephalography (EEG) or magnetoencephalography (MEG) reflect the neural underpinnings of WM. The WM processes that fluctuate in conjunction with WM demands are closely correlated with WM test performance, and their EEG signatures are abnormal in several clinical populations. Novel interventions such as transcranial magnetic stimulation (TMS) have been shown to modulate these oscillations and subsequently improve WM performance and clinical symptoms. Systematically identifying pathological WM-related gamma/theta oscillatory patterns with EEG/MEG and developing ways to target them with interventions such as TMS is an active area of clinical research. Results hold promise for enhancing the outcomes of our patients with WM deficits and for moving the field of clinical neuropsychology towards a mechanism-based approach.

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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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Differences of temporal dynamics and signal complexity of gamma band oscillations in first-episode psychosis during a working memory task

Cited by 4 publications

References 60 publications

Disruption of gamma–delta relationship related to working memory deficits in first-episode psychosis

Disruption of gamma–delta relationship related to working memory deficits in first-episode psychosis

Measurement and Modulation of Working Memory-Related Oscillatory Abnormalities

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

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