SZ Groups Research Articles

Lipidomics analysis reveals the effects of Schizochytrium sp. supplementation on the lipid composition of Tan sheep meat

Schizochytrium sp. (SZ) can potentially be employed in nutritional strategies for producing high-quality sheep meat. However, the effects of SZ on the lipid composition of sheep meat are insufficiently understood. In this study, the effects of SZ supplementation on the lipid profile of Tan sheep meat were evaluated using non-targeted lipidomic techniques. Lipidomics analysis revealed 383 differential lipids (DLs) between the SZ and control groups, and there were six metabolic pathways associated with lipids, including glycerophospholipid metabolism, glycerolipid metabolism, α-linolenic acid metabolism, linoleic acid metabolism, glycine, serine and threonine metabolism, and arachidonic acid metabolism (P < 0.05). Glycerophospholipid metabolism was the core pathway of DLs; we found that phosphatidylcholine, phosphatidylserine, and lysophosphatidylcholine were the crucial lipid metabolites of this pathway. Dietary supplementation with SZ increased n-3 polyunsaturated fatty acid (PUFA), C22:6n-3, and C20:5n-3 (P < 0.05), while it decreased C18:0, saturated fatty acid (SFA), and SFA/PUFA (P < 0.05). These results indicate that SZ supplementation induces positive alterations in the lipid profile of Tan sheep meat, which is beneficial to meat quality and sheds valuable insights into the future development of functional lipids in sheep meat.

Schizochytrium sp. and lactoferrin supplementation alleviates Escherichia coli K99-induced diarrhea in preweaning dairy calves

Calf diarrhea, a common disease mainly induced by Escherichia coli infection, is one of the main reasons for nonpredator losses. Hence, an effective nonantibacterial approach to prevent calf diarrhea has become an emerging requirement. This study evaluated the microalgae Schizochytrium sp. (SZ) and lactoferrin (LF) as a nutrient intervention approach against E. coli O101:K99-induced preweaning calve diarrhea. Fifty 1-d-old male Holstein calves were randomly divided into 5 groups (n = 10): (1) control, (2) blank (no supplement or challenge), (3) 1 g/d LF, (4) 20 g/d SZ, or (5) 1 g/d LF plus 20 g/d SZ (LFSZ). The experimental period lasted 14 d. On the morning of d 7, calves were challenged with 1 × 1011 cfu of E. coli O101:K99, and rectum feces were collected on 3, 12, 24, and 168 h postchallenge for the control, LF, SZ, and LFSZ groups. The rectal feces of the blank group were collected on d 14. Data were analyzed using the mixed procedure of SAS (version 9.4; SAS Institute Inc.). The E. coli K99 challenge decreased the average daily gain (ADG) and increased feed-to-gain ratio (F:G) and diarrhea frequency (control vs. blank). Compared with the control group, the LFSZ group had a higher ADG and lower F:G, and the LFSZ and SZ groups had lower diarrhea frequency compared with the control group. In addition, the LFSZ and SZ groups have no differences in diarrhea frequency compared with the blank group. Compared with the control group, the blank group had lower serum nitric oxide (NO), endothelin-1, d-lactic acid (D-LA), and lipopolysaccharide (LPS) concentrations, as well as serum IgG, IL-1β, IL-6, IL-10, and TNF-α levels on d 7 and 14. On d 7, compared with the control group, all treatment groups had lower serum NO level, the SZ group had a lower serum D-LA concentration, and the LF and LFSZ groups had lower serum LPS concentration. On d 14, compared with the control group, the fecal microbiota of the blank group had lower Shannon, Simpson, Chao1, and ACE indexes, the LFSZ group had lower Shannon and Simpson indexes, the SZ and LFSZ groups had a higher Chao1 index, and all treatment groups had a higher ACE index. In fecal microbiota, Bifidobacterium and Actinobacteria were negatively associated with IL-10 and d-lactate, while Akkermansia was negatively associated with endothelin-1 and positively correlated with LPS, fecal scores, and d-lactate levels. Our results indicated that LF and SZ supplements could alleviate E. coli O101:K99-induced calf diarrhea individually or in combination. Supplementing 1 g/d LF and 20 g/d SZ could be a potential nutrient intervention approach to prevent bacterial diarrhea in calves.

Aberrant Effective Connectivity During Eye Gaze Processing Is Linked to Social Functioning and Symptoms in Schizophrenia

BackgroundPatients with schizophrenia show abnormal gaze processing, which is associated with social dysfunction. These abnormalities are related to aberrant connectivity among brain regions that are associated with visual processing, social cognition, and cognitive control. In this study, we investigated 1) how effective connectivity during gaze processing is disrupted in schizophrenia and 2) how this may contribute to social dysfunction and clinical symptoms. MethodsThirty-nine patients with schizophrenia/schizoaffective disorder (SZ) and 33 healthy control participants completed an eye gaze processing task during functional magnetic resonance imaging. Participants viewed faces with different gaze angles and performed explicit and implicit gaze processing. Four brain regions—the secondary visual cortex, posterior superior temporal sulcus, inferior parietal lobule, and posterior medial frontal cortex—were identified as nodes for dynamic causal modeling analysis. ResultsBoth the SZ and healthy control groups showed similar model structures for general gaze processing. Explicit gaze discrimination led to changes in effective connectivity, including stronger excitatory, bottom-up connections from the secondary visual cortex to the posterior superior temporal sulcus and inferior parietal lobule and inhibitory, top-down connections from the posterior medial frontal cortex to the secondary visual cortex. Group differences in top-down modulation from the posterior medial frontal cortex to the posterior superior temporal sulcus and inferior parietal lobule were noted, such that these inhibitory connections were attenuated in the healthy control group but further strengthened in the SZ group. Connectivity was associated with social dysfunction and symptom severity. ConclusionsThe SZ group showed notably stronger top-down inhibition during explicit gaze discrimination, which was associated with more social dysfunction but less severe symptoms among patients. These findings help pinpoint neural mechanisms of aberrant gaze processing and may serve as future targets for interventions that combine neuromodulation with social cognitive training.

Differences in social perception in people with schizophrenia and bipolar disorder

People with schizophrenia have difficulties recognizing other people's expressions, emotional states, and intentions; however, much less is known about their ability to perceive and understand social interactions. We used scenes depicting social situations to compare responses from 90 volunteers (healthy controls [HC], schizophrenia [SZ], and bipolar disorder [BD] outpatients from the Hospital del Salvador in Valparaíso, Chile) to the question: “What do you think is happening in the scene?” Independent blind raters assigned a score of 0 (absent), 1 (partial), or 2 (present) for each item based on whether the description identifies a) the context, b) the people, and c) the interaction depicted in the scenes. Regarding the context of the scenes, the SZ and BD groups scored significantly lower than the HC group, with no significant difference between the SZ and BD groups. Regarding the identification of the people and the interactions, the SZ group scored lower than the HC and BD groups, with no significant difference between the HC and BD groups. An ANCOVA was used to examine the relationship between diagnosis, cognitive performance, and the results of the social perception test. The diagnosis had an effect on context (p = .001) and people (p = .0001) but not on interactions (p = .08). Cognitive performance had a significant effect on interactions (p = .008) but not on context (p = .88) or people (p = .62). Our main result is that people with schizophrenia may have significant difficulties perceiving and understanding social encounters between other people.

Cortical anatomical variations, gene expression profiles, and clinical phenotypes in patients with schizophrenia

Background and HypothesisSchizophrenia (SZ) patients display significant structural brain abnormalities; nevertheless, the genetic mechanisms regulating cortical anatomical variations and their correlation with the disease phenotype are still ambiguous. Study DesignWe characterized anatomical variation using a surface-based method derived from structural magnetic resonance imaging of patients with SZ and age- and sex-matched healthy controls (HCs). Partial least-squares regression was performed across cortex regions between anatomical variation and average transcriptional profiles of SZ risk genes and all qualified genes from the Allen Human Brain Atlas. The morphological features of each brain region were correlated to symptomology variables in patients with SZ using partial correlation analysis. Study ResultsA total of 203 SZ and 201 HCs were included in the final analysis. We observed significant variation of 55 regions of cortical thickness, 23 regions of volume, 7 regions of area, and 55 regions of local gyrification index (LGI) between SZ and HC groups. Expression profiles of 4 SZ risk genes and 96 genes from all qualified genes showed a correlation to anatomical variability, however, after multiple comparisons, the correlations were no longer significant. LGI variability in multiple frontal subregions was associated with specific symptoms of SZ, whereas cognitive function involving attention/vigilance was linked to LGI variability across nine brain regions. ConclusionsCortical anatomical variation of patients with schizophrenia is associated with gene transcriptome profiles as well as clinical phenotypes.

A Pilot Study of Service Utilisation Pathways of Patients With Distinct Psychotic and Antisocial Typologies

AimsThere is a developing body of research that suggests that there may be distinct categories of patients that can explain the relationship between psychosis and antisocial behaviours. Specifically, three pathways of offending, antisocial behaviour and psychosis have been described and there is an evolving empirical evidence base to suggest that these pathways are aetiologically distinct. Firstly, there is a pathway for early-start offenders, which have been identified as those with psychosis preceded by Conduct Disorder (SZ + CD). Secondly, a group that start to display antisocial behaviours in parallel to the onset of psychosis (SZ-AS). The third group involves those with a long history of a psychotic disorder and no history of antisocial behaviours, who will present to services following a first conviction for non-violent or violent crime (SZ). The authors hypothesise that each typology will utilise services differently throughout the clinical trajectory. This pilot study aimed to (i) examine the concurrent validity of the antisocial behaviour and psychosis typologies, and (ii) examine differences in the service utilisation patterns of patients between these groups.MethodsThe sample consisted of adult male patients admitted to low and medium secure forensic hospitals within the Northwest of England. A total of 90 patients were used.A categorisation checklist was developed, and the typology of patients determined from data collected from electronic health records. Data were collected on patient demographics, psychiatric diagnosis, aetiological factors, and service utilisation. Two researchers reviewed the data and determined the typology. Statistical analysis aimed to assess the difference in aetiological variables between the typologies and examine the relationship with how each typology utilised services.ResultsThis study provided further evidence of distinguishing characteristics emphasising typology heterogeneity.The CD-SZ group were more likely to have utilised mental health services &lt;18 years (70%, p = 0.062), and to have used services preceding a diagnosis of psychosis (60%, p = 0.011). Following the onset of a psychotic disorder, the AS-SZ and SZ groups had a higher proportion that used general adult psychiatry services (p = 0.031), with CD-SZ coming in to contact with forensic psychiatry services and criminal justice services earlier and more frequently.ConclusionThis study demonstrates that each typology has a different clinical trajectory through mental health services. This provides further empirical evidence towards different clinical typologies and trajectories of individuals with psychosis and anti-social behaviour. Understanding more about how these typologies utilise services will enable clinicians to introduce interventions help develop effective management plans that address the distinct characteristics of each typology of offender with psychosis.

Event-related potential correlates of affective response inhibition in bipolar I disorder: Comparison with schizophrenia

BackgroundIndividuals with bipolar I disorder (BD) have difficulty inhibiting context-inappropriate responses. The neural mechanisms contributing to these difficulties, especially in emotional contexts, are little understood. This study aimed to inform mechanisms of impaired impulsivity control in response to emotion in BD, and whether response inhibition indices are altered to a similar degree in schizophrenia spectrum disorders (SZ). We examined alterations to behavioral performance and event-related potentials (ERPs) during inhibition to affective stimuli in BD, relative to healthy control participants (HC) and SZ. MethodsSixty-six participants with BD, 32 participants with SZ, and 48 HC completed a Go/No-Go task with emotional face stimuli while electroencephalography was recorded. Behavioral signal detection metrics (perceptual sensitivity, response bias) and ERPs (N200, P300) were compared across groups. ResultsRelative to HC, participants with BD showed reduced (1) discrimination of Go vs. No-Go stimuli (i.e., emotional vs. neutral faces), and (2) P300 amplitudes elicited by emotional faces. Results similarly extended to SZ: BD and SZ groups did not differ on behavioral performance nor ERP amplitudes. LimitationsAspects of the Go/No-Go task design may have limited findings, and medication effects on ERP amplitudes in patient samples cannot be fully ruled out. ConclusionsFindings suggest the difficulty participants with BD and SZ experienced on the current affective response inhibition task lied largely in discriminating between facial expressions. Difficulties with discriminating emotional from neutral expressions may contribute to difficulties with appropriate behavioral responding in social-affective contexts for individuals with BD and SZ.

The Prominent Deck B Phenomenon in Schizophrenia: An Empirical Study on Iowa Gambling Task.

Background: The Iowa Gambling Task (IGT) was established to evaluate emotion-based decision-making ability under uncertain circumstances in clinical populations, including schizophrenia (Sz). However, there remains a lack of stable behavioral measures regarding discrimination for decision-making performance in IGT between schizophrenic cases and healthy participants. None of the Sz-IGT studies has specifically verified the prominent deck B (PDB) phenomenon gradually revealed in other populations. Here, we provided a global review and empirical study to verify these Sz-IGT issues.Methods: Seeking reliable and valid behavioral measures, we reviewed 38 studies using IGT to investigate decision-making behavior in Sz groups. The IGT, the Wisconsin Card Sorting Test (WCST), and clinical symptoms evaluations were administered to 61 schizophrenia or schizoaffective cases diagnosed by psychiatrists and 62 demographically matched healthy participants.Results: There were no valid behavioral measures in IGT that could significantly identify the decision-making dysfunction of Sz. However, Sz cases, on average, made more choices from disadvantageous deck B relative to other decks, particularly in the later learning process (block 3–5). Compared to the control group, the Sz group was more impaired on the WCST. The high-gain frequency decks B and D showed significant correlations with WCST but no correlation between clinical symptoms and IGT/WCST.Conclusions: Gain–loss frequency (GLF) has a dominant and stable impact on the decision-making process in both Sz and control groups. PDB phenomenon is essentially challenging to be observed on the ground of the expected value (EV) viewpoint approach on the IGT in both populations. Consequently, caution should be exercised when launching the IGT to assess the decision-making ability of Sz under a clinical scenario.

Altered neuroaxonal integrity in schizophrenia and major depressive disorder assessed with neurofilament light chain in serum

BackgroundSchizophrenia (SZ) and major depressive disorders (MDD) have been frequently linked to anatomical brain alterations. However, the relationship between brain pathology, inflammation and clinical symptoms in these disorders is still unclear. Thus, by applying novel blood markers of neuroaxonal integrity such as neurofilament light chain (NfL), we can now address main issues in psychiatric research and potentially offer innovative diagnostic tools toward better clinical characterizations and monitoring in both SZ and MDD. MethodsNfL levels were measured in serum of 44 patients with SZ and in 41 patients with MDD applying single molecule array technology and compared to a healthy norm population. Main inflammatory markers (C- reactive protein, interleukins IL-6 and IL-10) were measured to define patients with inflammatory phenotype. The Digit Symbol Substitution Task (DSST) and the Letter-Number-Sequencing Task were performed to estimate cognitive function in both groups. ResultsNfL levels in MDD group (but not in SZ group) were significantly higher than reference values of healthy norm population. A higher than expected proportion of patients with NfL levels above age-specific cut-off values was observed in both SZ and MDD groups. No correlation was observed between NfL and inflammatory markers. A negative correlation between DSST and NfL-values was observed in patients with MDD. ConclusionsBoth SZ and MDD showed elevated serum levels of NfL, which were independent from inflammatory markers but associated with cognitive performance.

Association of Mitochondrial Biogenesis With Variable Penetrance of Schizophrenia

Discovery of mechanisms that underlie variable penetrance for neuropsychiatric illness in the context of genetic variants that carry elevated risk can advance novel treatment approaches for these disorders. To test the hypothesis that mitochondrial compensation is associated with the variable penetrance of schizophrenia in the 22q11.2 deletion syndrome (22q11DS). This case-control study compared measures of mitochondrial function and the expression of related genes in 14 induced pluripotent stem cell-derived neurons from typically developing control individuals (6 lines) and from adults with 22q11DS (8 lines). The individuals with 22q11DS included 2 groups, those carrying a diagnosis of schizophrenia and those without this diagnosis (4 lines each). Similar measures were made of lymphoblastic cells lines (LCLs) from a separate group of adults with 22q11DS with (10 lines) or without (8 lines) schizophrenia. The study included samples derived from a clinical setting. The induced pluripotent stem cell lines were derived from individuals with 22q11DS with or without a diagnosis of schizophrenia at Stanford University. The LCLs were from adults within the 22q and You Center at the Children's Hospital of Philadelphia. Data were analyzed between July 1, 2019, and January 24, 2021. Total adenosine triphosphate (ATP), oxidative phosphorylation (OXPHOS) complex activity, and messenger RNA expression via reverse transcription-polymerase chain reaction of selected genes encoding for mitochondrial proteins. Study participants included men and women aged 18 to 37 years. Of 32 participants, the mean (SD) age of men was 27 (1.9) years and of women was 29 (1.2) years. Replicating a previous study, neurons from the 22q11DS and schizophrenia (22q+Sz) group had reduced ATP levels (mean [SD], 15.6 [1.5] vs 21.9 [1.4]; P = .02) and reduced OXPHOS activity (ie, complex I; 1.51 [0.1] vs 1.89 [0.1]; P = .01). These deficits were not present in neurons from individuals with 22q11DS without schizophrenia (22q[-]Sz). In this group, the expression of multiple genes encoding OXPHOS subunits was significantly upregulated. For example, compared with control individuals, NDUFV2 expression was increased by 50% in the 22q(-)Sz group (P < .001) but not significantly changed in the 22q+Sz group. Expression of genes driving mitochondrial biogenesis, including PGC1α, showed a similar pattern of upregulation in the 22q(-)Sz group compared with the control and the 22q+Sz groups. Stimulation of mitochondrial biogenesis normalizes the ATP deficit seen in 22q+Sz neurons. Finally, using LCLs from a separate group of adults with 22q11DS, evidence for enhanced mitochondrial biogenesis was again found in the 22q(-)Sz group. In this study, an increase in mitochondrial biogenesis and function was associated with the absence of schizophrenia in neurons and LCLs from individuals with 22q11DS, but the deficit in the 22q+Sz group was reversible by agents that enhance mitochondrial biogenesis. Enhancement of mitochondrial biogenesis may provide a targetable opportunity for treatment or prevention of this disorder in individuals with 22q11DS.

The impact of the COVID-19 pandemic on negative symptoms in individuals at clinical high-risk for psychosis and outpatients with chronic schizophrenia.

Negative symptoms are core features of schizophrenia-spectrum disorders that are frequently observed across all phases of illness. By their nature, COVID-19 social isolation, physical distancing, and health precautions induce behavioural aspects of negative symptoms. However, it is unclear whether these prevention measures also lead to increases in experiential negative symptoms, whether such effects are equivalent across individual negative symptom domains, and if exacerbations occur equivalently across phases of illness. The current study compared negative symptom severity scores obtained during the pandemic to pre-pandemic assessments in two samples: (1) outpatients with chronic schizophrenia (SZ: n = 32) and matched healthy controls (CN: n = 31) and (2) individuals at clinical high risk for psychosis (CHR: n = 25) and matched CN (n = 30). Pre-pandemic ratings of negative symptoms were clinically elevated in SZ and CHR groups, which did not differ from each other in severity. In SZ, ratings obtained during the pandemic were significantly higher than pre-pandemic ratings for all 5 domains (alogia, blunted affect, anhedonia, avolition, and asociality) and item-level analyses indicated that exacerbations occurred on both experiential and behavioral symptoms of anhedonia, avolition, and asociality. In contrast, CHR only exhibited increases in anhedonia and avolition items during the pandemic compared to pre-ratings. Findings suggest that negative symptoms should be a critical treatment target during and after the pandemic in the schizophrenia spectrum given that they are worsening and critically related to risk for conversion, functional outcome, and recovery.

Heschl's Gyrus Duplication Pattern in Individuals at Risk of Developing Psychosis and Patients With Schizophrenia.

An increased prevalence of duplicated Heschl’s gyrus (HG), which may reflect an early neurodevelopmental pathology, has been reported in schizophrenia (Sz). However, it currently remains unclear whether individuals at risk of psychosis exhibit similar brain morphological characteristics. This magnetic resonance imaging study investigated the distribution of HG gyrification patterns [i.e., single HG, common stem duplication (CSD), and complete posterior duplication (CPD)] and their relationship with clinical characteristics in 57 individuals with an at-risk mental state (ARMS) [of whom 5 (8.8%) later developed Sz], 63 patients with Sz, and 61 healthy comparisons. The prevalence of duplicated HG patterns (i.e., CSD or CPD) bilaterally was significantly higher in the ARMS and Sz groups than in the controls, whereas no significant differences were observed in HG patterns between these groups. The left CSD pattern, particularly in the Sz group, was associated with a verbal fluency deficit. In the ARMS group, left CSD pattern was related to a more severe general psychopathology. The present results suggest that an altered gyrification pattern on the superior temporal plane reflects vulnerability factors associated with Sz, which may also contribute to the clinical features of high-risk individuals, even without the onset of psychosis.

Copy number variations of satellite III (1q12) and ribosomal repeats in health and schizophrenia

ObjectiveEarlier we studied the copy number variations (CNVs) of ribosomal repeat (rDNA) and the satellite III fragment (1q12) (f-SatIII) in the cells of schizophrenia patients (SZ) and healthy controls (HC). In the present study we pursued two main objectives: (1) to confirm the increased rDNA and decreased f-SatIII content in the genomes of enlarged SZ and HC samples and (2) to compare the rDNA and f-SatIII content in the same DNA samples of SZ and HC individuals. MethodsWe determined the rDNA CN and f-SatIII content in the genomes of leukocytes of 1770 subjects [HC (N = 814) and SZ (N = 956)]. Non-radioactive quantitative hybridization method (NQH) was applied for analysis of the various combinations of the two repeats sizes in SZ and HC groups. Resultsf-SatIII in human leukocytes (N = 1556) varies between 5.7 and 44.7 pg/ng DNA. RDNA CN varies between 200 and 896 (N = 1770). SZ group significantly differ from the HC group by lower f-SatIII content and by rDNA abundance. The f-SatIII and rDNA CN are not randomly combined in the genome. Higher rDNA CN values are associated with higher f-SatIII index values in SZ and HC. The f-SatIII variation interval in SZ group increases significantly in the subgroup with the high rDNA CN index values (>300 copies). ConclusionSchizophrenia patients' genomes contain low number of f-SatIII copies corresponding with a large ribosomal repeats CN. A scheme is proposed to explain the low f-SatIII content in SZ group against the background of high rDNA CN.

Gray Matter Changes in the Insular Cortex During the Course of the Schizophrenia Spectrum.

Progressive gray matter reductions in the insular cortex have been reported in the early phases of schizophrenia (Sz); however, the trajectory of these reductions during the course of the illness currently remains unclear. Furthermore, it has not yet been established whether patients with schizotypal (SzTypal) features exhibit progressive changes in the insular cortex. This follow-up magnetic resonance imaging study examined volume changes in the short and long insular cortices (mean inter-scan interval = 2.6 years) of 23 first-episode (FE) and 17 chronic patients with Sz, 14 with SzTypal disorder, and 21 healthy controls. Baseline comparisons revealed smaller insular cortex volumes bilaterally in Sz patients (particularly in the chronic group) than in SzTypal patients and healthy controls. FESz patients showed significantly larger gray matter reductions in the insular cortex over time (left: −3.4%/year; right: −2.9%/year) than those in healthy controls (−0.1%/year for both hemispheres) without the effect of subregion or antipsychotic medication, whereas chronic Sz (left: −1.5%/year; right: −1.6%/year) and SzTypal (left: 0.5%/year; right: −0.6%/year) patients did not. Active atrophy of the right insular cortex during FE correlated with fewer improvements in positive symptoms in the Sz groups, while mild atrophy of the left insular cortex during the chronic phase was associated with the severity of negative symptoms in the follow-up period. The present results support dynamic volumetric changes in the insular cortex being specific to overt Sz among the spectrum disorders examined and their degree and role in symptomatology appear to differ across the illness stages.

T131. EVENT RELATED POTENTIALS (ERPS) DURING FREE VIEWING OF IMAGES WITH INCREASING SEMANTIC COMPLEXITY IN SUBJECTS’ AFFECTED WITH SCHIZOPHRENIA

BackgroundCurrently, the diagnosis of schizophrenia is made solely based on interviews and behavioral observations by a trained psychiatrist. Technologies such as electroencephalography (EEG) are used for differential diagnosis and not to support the psychiatrist’s positive diagnosis. Here, we show the potential of EEG recordings as biomarkers of the schizophrenia syndrome. EEG (electroencephalography) differences between patients with schizophrenia (SCZ) and controls have been reported. Tasks used are complex and specialized, not necessarily resemble natural stimuli/ environment to which the brain is adapted. We tested if SCZ global cognitive deficits could be described by EEG features using an ecological and simple approach.MethodsWe recorded EEG while schizophrenia patients freely viewed natural scenes, and we analyzed the average EEG activity locked to the image onset. We compared occipital ERPs obtained from 11 subjects with SCZ and 9 aged-‐ matched healthy controls (HC) during free-‐ exploration of images. Image categories included Plain Gray, Pink Noise and Landscapes (n=10 each). ERPs locked to image onset were obtained from occipital electrodes ader ocular artifacts rejection (by ICA decomposition).ResultsWe found significant differences between patients and healthy controls in occipital areas approximately 500 ms after image onset. These differences were used to train a classifier to discriminate the schizophrenia patients from the controls. The best classifier had 81% sensitivity for the detection of patients and specificity of 59% for the detection of controls, with an overall accuracy of 71%. We observed a positive wave after NS (natural scenes) landscape image onset, with late differences between the SZ patients and HCs. After visual inspection of the ERPs from each area (frontal, central, parietal, and occipital), we found significant differences only in the occipital ERP. It had two positive peaks in the HCs but a reduced second peak in the SZ patients. The median ERP at 0.4–0.6 s after image onset for the HCs was 4.14 μ V and 1.55 μ V for the SZ patients. The patients had a significant decrease in their ERP amplitude compared to the HCs (p = 0.01, Z = −2.5, T = 82, WRS test). Only the occipital electrodes showed differences in this period with the NS images. No other differences between the HC and SZ groups were found at other locations or time periods.We found significant differences between HC and SZ groups at the occipital electrodes only for the NS. Neither gray (p = 0.29, Z = −1.06, T = 101, WRS test) nor pink noise images (p = 0.93, Z = −0.07, T = 114, WRS test) showed significant differences between the HCs and SZ patients at any group of electrodes at this or any other time period.With an accuracy of 71% we are able to classified subjects. We performed 1350 cross-‐validation leaving 4 subjects out (two SCZ and two controls). 70.5% of the subjects with schizophrenia were correctly detected.DiscussionThis study shows that EEG features can differentiate between SCZ and HC in a simple, instruction-‐free visual task. Differences in late potentials (>300 ms) and in more complex images suggests deficits in top-‐down (cognitive) rather than bottom-‐up (perception) mechanisms.These results indicate that EEG signals from a free-viewing paradigm discriminate patients from healthy controls and have the potential to become a tool for the psychiatrist to support the positive diagnosis of schizophrenia.

Corpus callosum microstructural and macrostructural abnormalities in schizophrenia according to the stage of disease

Corpus callosum (CC) volume and surface (macrostructural) studies remain controversial and have not considered the illness duration (ID) systematically. Regardless of ID, some CC macrostructural studies have shown no difference between SZ patients and healthy controls (HC), whereas others have reported macrostructural abnormalities in SZ. Conversely, CC microstructural studies are more in agreement with alterations in CC integrity regardless of the patients’ ID, but the direction and degree of these abnormalities over time remain unknown. Moreover, no study has explored both the micro- and macrostructure of the CC in SZ by considering the stage of disease. Both CC micro- and macrostructural data were investigated in 43 SZ patients and compared between two patient groups (21 patients with a short ID and 22 with a long ID) and HC (23 participants) using diffusion tensor and structural imaging. CC microstructural alterations were detected in both SZ groups compared to the HC group, without differences between the SZ groups. In contrast, CC macrostructural alterations were only found in the long ID group. CC microstructural alterations might be detected in schizophrenia at an early stage, without an increase of magnitude thereafter, while CC macrostructural alterations might become apparent at later stages of the illness.

Reduced pineal gland volume across the stages of schizophrenia

A few magnetic resonance imaging (MRI) studies reported reduced pineal gland volume in chronic schizophrenia (Sz), implicating the involvement of melatonin in the pathophysiology of the illness. However, it is not known whether this abnormality, if present, exists at the early illness stages and/or develops progressively over the course of the illness. This MRI study examined pineal gland volume in 64 patients with first-episode schizophrenia (FESz), 40 patients with chronic Sz, 22 individuals with at-risk mental state (ARMS), and 84 healthy controls. Longitudinal changes in pineal volume (mean inter-scan interval = 2.5 ± 0.7 years) were also examined in a subsample of 23 FESz, 16 chronic Sz, and 21 healthy subjects. In the cross-sectional comparison, the ARMS, FESz, and chronic Sz groups had significantly smaller pineal volume to the same degree as compared with healthy controls. A longitudinal comparison demonstrated that pineal volume did not change over time in any group. There was no association between pineal volume and clinical variables (e.g., symptom severity, medication) in the ARMS and Sz groups. The results suggest that a smaller pineal gland may be a static vulnerability marker of Sz, which probably reflects an early neurodevelopmental abnormality.

Cognition sociale dans la schizophrénie et les troubles du spectre de l’autisme : points de convergences et différences fonctionnelles

IntroductionSchizophrenia and autistic spectrum disorder (ASD) are two neurodevelopmental disorders that have different symptom presentations, ages of onset and developmental courses. Both schizophrenia and ASD are characterized by marked deficit in communication, social interactions, affects and emotions. Social cognitive impairments in ASD and schizophrenia were demonstrated separately in both disorders. It was reported that these impairments have direct relation with social deficits of both disorders. The apparent similarity between social cognition impairments in ASD and schizophrenia highlights questions about the existence of common or different neurocognitive mechanisms related to social dysfunctions. In order to examine these questions, the present article provides a comprehensive review of all published studies which directly compare individuals with ASD and schizophrenia on the same cognitive tasks of social cognition. MethodsThe article search was made on Pubmed, PsycInfo and ScienceDirect, with the items: “autism”, “Asperger syndrome”, “schizophrenia”, “social cognition”, “theory of mind”, “emotional processing”, “social perception”, “attributions style”. All published studies which compared individuals with ASD and schizophrenia, (diagnosed according to DSM-IV (APA, 1994) criteria and IQ≥70), included control group were considered. The cognitive tasks were categorized according to four domains of social cognition defined by SCOPE (Pinkham et al., 2013): theory of mind (ToM), emotional processing (EP), social perception (SP) and attributional style/bias. The results were analyzed in terms of performances, cognitive profile and patterns of neural activations. Twenty-one published studies and two meta-analytic reviews were analyzed. ResultsCognitive performance analysis confirms the convergence of abnormalities of people with autism and people with schizophrenia on 1st and 2nd order theory of mind, emotion processing and social perception. Quantitative results show reduced performance in ASD compared to SZ and Ct groups. Differences were observed between ASD and SZ regarding social situation comprehension, visual orientation and visuospatial exploration strategies, and attributional style highlighting different strategies on intentional process. Brain imaging studies show that people with autism present a reduced cerebral activity in several key regions of theory of mind (cingulate regions, superior temporal sulcus, paracentral lobule), and emotional treatment (primary and secondary somatosensory regions), while people with SZ exhibit an inappropriate increased activity in these regions. ConclusionThe present revue of the studies which directly compare individuals with ASD and schizophrenia on different domains of social cognition indicates that both disorders exhibit differences and similarities with regard to behavioral performances. Results in neuroimaging indicate different neurocognitive mechanisms underlie apparently similar social-cognitive impairments. Further studies are needed to better explore and describe divergent neurocognitive mechanisms in ASD and schizophrenia in order to provide treatment and remediation methods that take into account the specificities of neurocognitive processes in the two disorders.

Shared and Distinct Functional Architectures of Brain Networks Across Psychiatric Disorders.

Brain network alterations have increasingly been implicated in schizophrenia (SCZ), bipolar disorder (BD), and major depressive disorder (MDD). However, little is known about the similarities and differences in functional brain networks among patients with SCZ, BD, and MDD. A total of 512 participants (121 with SCZ, 100 with BD, 108 with MDD, and 183 healthy controls, matched for age and sex) completed resting-state functional magnetic resonance imaging at a single site. Four global measures (the clustering coefficient, the characteristic shortest path length, the normalized clustering coefficient, and the normalized characteristic path length) were computed at a voxel level to quantify segregated and integrated configurations. Inter-regional functional associations were examined based on the Euclidean distance between regions. Distance strength maps were used to localize regions with altered distances based on functional connectivity. Patient groups exhibited shifts in their network architectures toward randomized configurations, with SCZ>BD>MDD in the degree of randomization. Patient groups displayed significantly decreased short-range connectivity and increased medium-/long-range connectivity. Decreases in short-range connectivity were similar across the SZ, BD, and MDD groups and were primarily distributed in the primary sensory and association cortices and the thalamus. Increases in medium-/long-range connectivity were differentially localized within the prefrontal cortices among the patient groups. We highlight shared and distinct connectivity features in functional brain networks among patients with SCZ, BD, and MDD, which expands our understanding of the common and distinct pathophysiological mechanisms and provides crucial insights into neuroimaging-based methods for the early diagnosis of and interventions for psychiatric disorders.

Orbitofrontal sulcogyral morphology is a transdiagnostic indicator of brain dysfunction.

Atypical sulcogyral patterns in the orbitofrontal cortex (OFC) are associated with increased risk for schizophrenia, as well as with quantitative traits associated with schizophrenia, such as anhedonia. Here we conduct a cross-diagnostic comparison to assess whether atypical OFC sulcogyral patterns confer risk for multiple brain disorders. We examined structural images from 4 groups of adult participants (N = 189), including those diagnosed with schizophrenia (SZ; N = 49), bipolar disorder (BP; N = 46), attention deficit hyperactivity disorder (ADHD; N = 41), and controls (N = 53). OFC sulcogyral pattern types were determined based on the continuity of the medial and lateral orbitofrontal sulcus. Chi-square analysis was performed to compare the sulcogyral pattern frequency distributions between patient groups and controls. We find that both SZ and BP groups had atypical pattern distributions, with increased atypical pattern frequencies relative to controls in the left hemisphere, consistent with the overlapping clinical features and genetic etiology of these disorders (SZ: χ2 = 17.6; p < 0.001; BP: χ2 = 19.2, p < 0.001). The ADHD group distribution did not significantly differ from controls (χ2 = 5.5; p = 0.06, NS.). Similar sulcogyral pattern frequencies across BP and SZ suggest that the sulcogyral phenotype may map more directly to a trait that is transdiagnostic. These results suggest that sulcogyral patterns present a novel morphological indicator for increased susceptibility to multiple psychiatric diagnoses.