Spectral decomposition of resting state electroencephalogram reveals unique theta/alpha activity in schizophrenia.

Resting state electroencephalographic (EEG) activity in schizophrenia (SZ) is frequently characterised by increased power at slow frequencies and/or a reduction of peak alpha frequency. Here we investigated the nature of these effects. As most studies to date have been limited by reliance on a priori frequency bands which impose an assumed structure on the data, we performed a data-driven analysis of resting EEG recorded in SZ patients and healthy controls (HC).

Decreased BOLD signals elicited by 40-Hz auditory stimulation of the right primary auditory cortex in bipolar disorder: An fMRI study.

Background: A number studies have been conducted on abnormalities in the cortical circuitry of gamma oscillations, including deficit in auditory steady-state response (ASSR) to gamma-frequency (≧ 30-Hz) stimulation, in patients with bipolar disorder (BD). In the current study, we investigated neural responses during click stimulation by blood oxygen level-dependent (BOLD) signals. We focused on Broadman 41 and 42, the main sources of ASSR.

Neuronal imbalance of excitation and inhibition in schizophrenia: a scoping review of gamma-band ASSR findings.

Recent empirical findings suggest that altered neural synchronization, which is hypothesized to be associated with an imbalance of excitatory (E) and inhibitory (I) neuronal activities, may underlie a core pathophysiological mechanism in patients with schizophrenia. The auditory steady-state response (ASSR) examined by electroencephalography (EEG) and magnetoencephalography (MEG) has been proposed as a potential biomarker for evaluating altered neural synchronization in schizophrenia. For this review, we performed a comprehensive literature search for papers published between 1999 and 2021 examining ASSRs in patients with schizophrenia.

Correlation between Post-Acute Electroconvulsive Therapy Alpha-Band Spectrum Power Increase and Improvement of Psychiatric Symptoms.

The results of quantitative electroencephalography (qEEG) studies on electroconvulsive therapy (ECT) have been inconsistent, and indicators of the efficacy of ECT have not been clearly identified. In this study, we examined whether qEEG could be used as an indicator of the effect of ECT by measuring it during the course of treatment. We analyzed qEEG data before and after acute-phase ECT in 18 patients with schizophrenia, mood disorders, and other psychiatric disorders.

Lower Hippocampal Volume in Patients with Schizophrenia and Bipolar Disorder: A Quantitative MRI Study.

Since patients with schizophrenia (SZ) and bipolar disorder (BD) share many biological features, detecting biomarkers that differentiate SZ and BD patients is crucial for optimized treatments. High-resolution magnetic resonance imaging (MRI) is suitable for detecting subtle brain structural differences in patients with psychiatric disorders. In the present study, we adopted a neuroanatomically defined and manually delineated region of interest (ROI) method to evaluate the amygdalae, hippocampi, Heschl's gyrus (HG), and planum temporale (PT), because these regions are crucial in the development of SZ and BD.

Correction: Behavioural cue reactivity to alcohol-related and non-alcohol-related stimuli among individuals with alcohol use disorder: An fMRI study with a visual task.

[This corrects the article DOI: 10.1371/journal.pone.

Neurophysiological Face Processing Deficits in Patients With Chronic Schizophrenia: An MEG Study.

Background: Neuropsychological studies have revealed that patients with schizophrenia (SZ) have facial recognition difficulties and a reduced visual evoked N170 response to human faces. However, detailed neurophysiological evidence of this face processing deficit in SZ with a higher spatial resolution has yet to be acquired. In this study, we recorded visual evoked magnetoencephalography (MEG) and examined whether M170 (a magnetic counterpart of the N170) activity deficits are specific to faces in patients with chronic SZ.

Behavioural cue reactivity to alcohol-related and non-alcohol-related stimuli among individuals with alcohol use disorder: An fMRI study with a visual task.

Patients with alcohol use disorder (AUD) have difficulty controlling their alcohol cravings and thus exhibit increased use and early relapse. Although patients tend to respond more strongly to alcohol-related images than to non-alcohol-related images, few researchers have examined the factors that modulate cravings. Here, we examined whole-brain blood oxygen level-dependent (BOLD) responses to behavioural cues in individuals with AUD and in healthy controls (HCs).

Longitudinal evaluation of visual P300 amplitude in clinical high-risk subjects: An event-related potential study.

Aim: We previously reported abnormal P300 and N200 in a visual oddball task, and progressive P300 amplitude reduction at 1-year follow-up in patients with first-episode schizophrenia. P300 reduction as well as intact P1/N1 were also observed in clinical high-risk subjects (CHR), but whether or not these components change over time is unknown. This study evaluates, longitudinally, the visual P300, as well as P1, N1, and N200, in CHR.

Auditory Cortex Volume and Gamma Oscillation Abnormalities in Schizophrenia.

We investigated whether the gray matter volume of primary auditory cortex (Heschl's gyrus [HG]) was associated with abnormal patterns of auditory γ activity in schizophrenia, namely impaired γ synchronization in the 40-Hz auditory steady-state response (ASSR) and increased spontaneous broadband γ power. (The γ data were previously reported in Hirano et al, , 2015;72:813-821). Participants were 24 healthy controls (HC) and 23 individuals with chronic schizophrenia (SZ).

The efficacy of extended metacognitive training for psychosis: A randomized controlled trial.

This study investigated the efficacy of 10-module metacognitive training (MCT) among Japanese patients with schizophrenia by conducting a multicenter randomized controlled trial to test the influence of the most recent and extended version of MCT on positive symptoms. A six-center, randomized, assessor-blind, controlled trial between "treatment as usual" (TAU) and TAU + MCT was conducted. Fifty inpatients and outpatients with schizophrenia, schizotypal, and delusional disorders (ICD 10) were enrolled, then randomly assigned to TAU (n = 26) or TAU + MCT (n = 24).

Progressive reduction of auditory evoked gamma in first episode schizophrenia but not clinical high risk individuals.

The early auditory-evoked gamma band response (EAGBR) may serve as an index of the integrity of fast recurrent inhibition or synaptic connectivity in the auditory cortex, where abnormalities in individuals with schizophrenia have been consistently found. The EAGBR has been rarely investigated in first episode schizophrenia patients (FESZ) and individuals at clinical high risk (CHR) for schizophrenia, and never been compared directly between these populations nor evaluated longitudinally. Here we examined the EAGBR in FESZ, CHR, and matched healthy controls (HC) at baseline and 1-year follow-up assessments to determine whether the EAGBR was affected in these clinical groups, and whether any EAGBR abnormalities changed over time.

Neuroanatomical substrate of chronic psychosis in epilepsy: an MRI study.

There may be different neural bases between subjects with epilepsy only (EP) and interictal chronic epilepsy psychosis (EPS). However, there have been few structural MRI studies of EPS. The current study was conducted to investigate the neural substrate of EPS.

Phase-Amplitude Coupling of the Electroencephalogram in the Auditory Cortex in Schizophrenia.

Background: Cross-frequency interactions may coordinate neural circuits operating at different frequencies. While neural oscillations associated with particular circuits in schizophrenia (SZ) are impaired, few studies have examined cross-frequency interactions. Here we examined phase-amplitude coupling (PAC) in the electroencephalograms of individuals with SZ and healthy control subjects (HCs).

Right hemisphere pitch-mismatch negativity reduction in patients with major depression: An MEG study.

Background: The mismatch negativity (MMN) component of the event-related potential and its magnetic counterpart, the MMNm, are generated by a mismatch between the physical features of a deviant stimulus and a neuronal sensory-memory trace produced by repetitive standard stimuli. Deficits in the MMN/MMNm have been reported in patients with major depression; however, the results are inconsistent. The present study investigated the pitch-MMNm in patients with major depression using whole-head 306-channel magnetoencephalography (MEG).

Increased BOLD Signals Elicited by High Gamma Auditory Stimulation of the Left Auditory Cortex in Acute State Schizophrenia.

Recent MRI studies have shown that schizophrenia is characterized by reductions in brain gray matter, which progress in the acute state of the disease. Cortical circuitry abnormalities in gamma oscillations, such as deficits in the auditory steady state response (ASSR) to gamma frequency (>30-Hz) stimulation, have also been reported in schizophrenia patients. In the current study, we investigated neural responses during click stimulation by BOLD signals.

Differentiation between major depressive disorder and bipolar disorder by auditory steady-state responses.

Background: The auditory steady-state response (ASSR) elicited by gamma band neural oscillations has received considerable interest as a biomarker of psychiatric disorders. Although recent ASSR studies have reported that patients with bipolar disorder (BD) show altered ASSRs, little is known about ASSRs in patients with major depressive disorder (MDD). The aim of this study was to evaluate whether ASSRs in MDD subjects differed from those in BD subjects or normal controls (NC).

Spontaneous Gamma Activity in Schizophrenia.

Importance: A major goal of translational neuroscience is to identify neural circuit abnormalities in neuropsychiatric disorders that can be studied in animal models to facilitate the development of new treatments. Oscillations in the gamma band (30-100 Hz) of the electroencephalogram have received considerable interest as the basic mechanisms underlying these oscillations are understood, and gamma abnormalities have been found in schizophrenia (SZ). Animal models of SZ based on hypofunction of the N-methyl-d-aspartate receptor (NMDAR) demonstrate increased spontaneous broadband gamma power, but this phenomenon has not been identified clearly in patients with SZ.

Clinical high risk and first episode schizophrenia: auditory event-related potentials.

The clinical high risk (CHR) period is a phase denoting a risk for overt psychosis during which subacute symptoms often appear, and cognitive functions may deteriorate. To compare biological indices during this phase with those during first episode schizophrenia, we cross-sectionally examined sex- and age-matched clinical high risk (CHR, n=21), first episode schizophrenia patients (FESZ, n=20) and matched healthy controls (HC, n=25) on oddball and novelty paradigms and assessed the N100, P200, P3a and P3b as indices of perceptual, attentional and working memory processes. To our knowledge, this is the only such comparison using all of these event-related potentials (ERPs) in two paradigms.

Progressive reduction of visual P300 amplitude in patients with first-episode schizophrenia: an ERP study.

Objective: To understand the underlying dynamic neurophysiological changes over the course of schizophrenia, it is important to study subjects longitudinally from the early stage of the illness. We previously reported that visual P300 was already impaired in patients with first-episode schizophrenia (FESZ). This study demonstrates how the visual P300, as well as earlier components P1, N1, and N200, changed at the 1-year follow-up after their initial measurement.

Preattentive dysfunction in patients with bipolar disorder as revealed by the pitch-mismatch negativity: a magnetoencephalography (MEG) study.

Objectives: Mismatch negativity (MMN) and its magnetic counterpart (MMNm) are thought to reflect an automatic process that detects a difference between an incoming stimulus and the sensory memory trace of preceding stimuli. In patients with schizophrenia, an attenuation of the MMN/MMNm amplitude has been repeatedly reported. Heschl's gyrus (HG) is one of the major generators of MMN and the functional alteration of HG has been reported in patients with bipolar disorder.

Review of neurophysiological findings in patients with schizophrenia.

Schizophrenia has been conceptualized as a failure of cognitive integration, and abnormalities in neural circuitry have been proposed as a basis for this disorder. In this article, we focus on electroencephalography and magnetoencephalography findings in patients with schizophrenia. Auditory-P50, -N100, and -P300 findings, visual-P100, -N170, and -N400 findings, and neural oscillations in patients with schizophrenia are overviewed.

Neurophysiological findings in patients with bipolar disorder.

The present article reviews findings from measuring evoked and event-related responses, neural oscillation and synchronization, and near-infrared spectroscopy (NIRS) studies in patients with bipolar disorder. Studies of evoked responses have indicated that the P50 suppression deficits may be related to the generation of psychosis and may constitute an endophenotype of bipolar disorder patients with psychotic features. The N100 may be intact in patients with bipolar disorder, and the N100 might be a biological index to distinguish bipolar disorder and schizophrenia.