Morphology of the lateral superior temporal gyrus in neuroleptic nai;ve patients with schizophrenia: relationship to symptoms

Meta-analysis of structural and functional brain abnormalities in early-onset schizophrenia

Background

Previous studies based on resting-state functional magnetic resonance imaging(rs-fMRI) and voxel-based morphometry (VBM) have demonstrated significant abnormalities in brain structure and resting-state functional brain activity in patients with early-onset schizophrenia (EOS), compared with healthy controls (HCs), and these alterations were closely related to the pathogenesis of EOS. However, previous studies suffer from the limitations of small sample sizes and high heterogeneity of results. Therefore, the present study aimed to effectively integrate previous studies to identify common and specific brain functional and structural abnormalities in patients with EOS.

Methods

The PubMed, Web of Science, Embase, Chinese National Knowledge Infrastructure (CNKI), and WanFang databases were systematically searched to identify publications on abnormalities in resting-state regional functional brain activity and gray matter volume (GMV) in patients with EOS. Then, we utilized the Seed-based d Mapping with Permutation of Subject Images (SDM-PSI) software to conduct a whole-brain voxel meta-analysis of VBM and rs-fMRI studies, respectively, and followed by multimodal overlapping on this basis to comprehensively identify brain structural and functional abnormalities in patients with EOS.

Results

A total of 27 original studies (28 datasets) were included in the present meta-analysis, including 12 studies (13 datasets) related to resting-state functional brain activity (496 EOS patients, 395 HCs) and 15 studies (15 datasets) related to GMV (458 EOS patients, 531 HCs). Overall, in the functional meta-analysis, patients with EOS showed significantly increased resting-state functional brain activity in the left middle frontal gyrus (extending to the triangular part of the left inferior frontal gyrus) and the right caudate nucleus. On the other hand, in the structural meta-analysis, patients with EOS showed significantly decreased GMV in the right superior temporal gyrus (extending to the right rolandic operculum), the right middle temporal gyrus, and the temporal pole (superior temporal gyrus).

Conclusion

This meta-analysis revealed that some regions in the EOS exhibited significant structural or functional abnormalities, such as the temporal gyri, prefrontal cortex, and striatum. These findings may help deepen our understanding of the underlying pathophysiological mechanisms of EOS and provide potential biomarkers for the diagnosis or treatment of EOS.

Association between homotopic connectivity and clinical symptoms in first-episode schizophrenia

Background

Abnormal functional connectivity (FC) in the brain has been observed in schizophrenia patients. However, studies on FC between homotopic brain regions are limited, and the results of these studies are inconsistent. The aim of this study was to compare homotopic connectivity between first-episode schizophrenia (FES) patients and healthy subjects and assess its correlation with clinical symptoms.

Methods

Thirty-one FES patients and thirty-three healthy controls (HC) were included in the study. The voxel-mirrored homotopic connectivity (VMHC) method of resting-state functional magnetic resonance imaging (rs-fMRI) was used to analyse the changes in homotopic connectivity between the two groups. The 5-factor PANSS model was used to quantitatively evaluate the severity of symptoms in FES patients. Partial correlation analysis was used to assess the correlation between homotopic connectivity changes and clinical symptoms.

Results

Compared to those in the HC group, VMHC values were decreased in the paracentral lobule (PL), thalamus, and superior temporal gyrus (STG) in the FES group (P < 0.05, FDR correction). No significant differences in white matter volume (WMV) within the subregion of the corpus callosum or in brain regions associated with reduced VMHC were observed between the two groups. Partial correlation analyses revealed that VMHC in the bilateral STG of FES patients was positively correlated with negative symptoms (rleft = 0.46, p < 0.05; rright = 0.47, p < 0.05), and VMHC in the right thalamus was negatively correlated with disorganized/concrete symptoms (rright = 0.45, p < 0.05).

Conclusion

Our study revealed that homotopic connectivity is altered in the resting-state brain of FES patients and correlates with the severity of negative symptoms; this change may be independent of structural changes in white matter. These findings may contribute to the development of the abnormal connectivity hypothesis in schizophrenia patients.

Morphometric Integrated Classification Index: A Multisite Model-Based, Interpretable, Shareable and Evolvable Biomarker for Schizophrenia

BACKGROUND AND HYPOTHESIS

Multisite massive schizophrenia neuroimaging data sharing is becoming critical in understanding the pathophysiological mechanism and making an objective diagnosis of schizophrenia; it remains challenging to obtain a generalizable and interpretable, shareable, and evolvable neuroimaging biomarker for schizophrenia diagnosis.

STUDY DESIGN

A Morphometric Integrated Classification Index (MICI) was proposed as a potential biomarker for schizophrenia diagnosis based on structural magnetic resonance imaging data of 1270 subjects from 10 sites (588 schizophrenia patients and 682 normal controls). An optimal XGBoost classifier plus sample-weighted SHapley Additive explanation algorithms were used to construct the MICI measure.

STUDY RESULTS

The MICI measure achieved comparable performance with the sample-weighted ensembling model and merged model based on raw data (Delong test, P > 0.82) while outperformed the single-site models (Delong test, P < 0.05) in either the independent-sample testing datasets from the 9 sites or the independent-site dataset (generalizable). Besides, when new sites were embedded in, the performance of this measure was gradually increasing (evolvable). Finally, MICI was strongly associated with the severity of schizophrenia brain structural abnormality, with the patients' positive and negative symptoms, and with the brain expression profiles of schizophrenia risk genes (interpretable).

CONCLUSIONS

In summary, the proposed MICI biomarker may provide a simple and explainable way to support clinicians for objectively diagnosing schizophrenia. Finally, we developed an online model share platform to promote biomarker generalization and provide free individual prediction services (http://micc.tmu.edu.cn/mici/index.html).

Deficits in Sense of Body Ownership, Sensory Processing, and Temporal Perception in Schizophrenia Patients With/Without Auditory Verbal Hallucinations

It has been claimed that individuals with schizophrenia have difficulty in self-recognition and, consequently, are unable to identify the sources of their sensory perceptions or thoughts, resulting in delusions, hallucinations, and unusual experiences of body ownership. The deficits also contribute to the enhanced rubber hand illusion (RHI; a body perception illusion, induced by synchronous visual and tactile stimulation). Evidence based on RHI paradigms is emerging that auditory information can make an impact on the sense of body ownership, which relies on the process of multisensory inputs and integration. Hence, we assumed that auditory verbal hallucinations (AVHs), as an abnormal auditory perception, could be linked with body ownership, and the RHI paradigm could be conducted in patients with AVHs to explore the underlying mechanisms. In this study, we investigated the performance of patients with/without AVHs in the RHI. We administered the RHI paradigm to 80 patients with schizophrenia (47 with AVHs and 33 without AVHs) and 36 healthy controls. We conducted the experiment under two conditions (synchronous and asynchronous) and evaluated the RHI effects by both objective and subjective measures. Both patient groups experienced the RHI more quickly and strongly than HCs. The RHI effects of patients with AVHs were significantly smaller than those of patients without AVHs. Another important finding was that patients with AVHs did not show a reduction in RHI under asynchronous conditions. These results emphasize the disturbances of the sense of body ownership in schizophrenia patients with/without AVHs and the associations with AVHs. Furthermore, it is suggested that patients with AVHs may have multisensory processing dysfunctions and internal timing deficits.

A systematic review of the neural correlates of multisensory integration in schizophrenia

Multisensory integration (MSI), in which sensory signals from different modalities are unified, is necessary for our comprehensive perception of and effective adaptation to the objects and events around us. However, individuals with schizophrenia suffer from impairments in MSI, which could explain typical symptoms like hallucination and reality distortion. Because the neural correlates of aberrant MSI in schizophrenia help us understand the physiognomy of this psychiatric disorder, we performed a systematic review of the current research on this subject. The literature search concerned investigated MSI in diagnosed schizophrenia patients compared to healthy controls using brain imaging. Seventeen of 317 identified studies were finally included. To assess risk of bias, the Newcastle-Ottawa quality assessment was used, and the review was written according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). The results indicated that multisensory processes in schizophrenia are associated with aberrant, mainly reduced, neural activity in several brain regions, as measured by event-related potentials, oscillations, activity and connectivity. The conclusion is that a fronto-temporal region, comprising the frontal inferior gyrus, middle temporal gyrus and superior temporal gyrus/sulcus, along with the fusiform gyrus and dorsal visual stream in the occipital-parietal lobe are possible key regions of deficient MSI in schizophrenia.

Neuroanatomical abnormalities in first-episode psychosis across independent samples: a multi-centre mega-analysis

BACKGROUND

Neuroanatomical abnormalities in first-episode psychosis (FEP) tend to be subtle and widespread. The vast majority of previous studies have used small samples, and therefore may have been underpowered. In addition, most studies have examined participants at a single research site, and therefore the results may be specific to the local sample investigated. Consequently, the findings reported in the existing literature are highly heterogeneous. This study aimed to overcome these issues by testing for neuroanatomical abnormalities in individuals with FEP that are expressed consistently across several independent samples.

METHODS

Structural Magnetic Resonance Imaging data were acquired from a total of 572 FEP and 502 age and gender comparable healthy controls at five sites. Voxel-based morphometry was used to investigate differences in grey matter volume (GMV) between the two groups. Statistical inferences were made at p < 0.05 after family-wise error correction for multiple comparisons.

RESULTS

FEP showed a widespread pattern of decreased GMV in fronto-temporal, insular and occipital regions bilaterally; these decreases were not dependent on anti-psychotic medication. The region with the most pronounced decrease - gyrus rectus - was negatively correlated with the severity of positive and negative symptoms.

CONCLUSIONS

This study identified a consistent pattern of fronto-temporal, insular and occipital abnormalities in five independent FEP samples; furthermore, the extent of these alterations is dependent on the severity of symptoms and duration of illness. This provides evidence for reliable neuroanatomical alternations in FEP, expressed above and beyond site-related differences in anti-psychotic medication, scanning parameters and recruitment criteria.

Less reduced gray matter volume in the subregions of superior temporal gyrus predicts better treatment efficacy in drug-naive, first-episode schizophrenia

Decreased gray matter volume (GMV) in the superior temporal gyrus (STG) has been implicated in the neurophysiology of schizophrenia. However, it remains unclear whether volumetric reduction in the subregions of the STG can predict treatment efficacy for schizophrenia. Our cohort included 44 drug-naive, first-episode patients, 42 unaffected siblings and 44 healthy controls. Voxel-based morphometry and pattern classification were utilized to analyze the acquired imaging data as per the anatomical subdivision by a well-defined brainnetome atlas. The patients presented lower GMV values in left TE1.0/1.2 (TE, anterior temporal visual association area) than the siblings, and lower GMV values in the left/right TE1.0/1.2 and left A22r (rostral area 22) than the controls. A positive correlation is observed between the GMV values in the right A38l (lateral area 38) and baseline Positive and Negative Syndrome Scale (PANSS) total scores in the patients. Support vector regression (SVR) results exhibited a significant association between predicted (based on the GMV values in the right A38l) and actual symptomatic improvement based on the reduction ratio of the PANSS total scores (r = 0.498, p = 0.001). Our results suggest that normal structure in the right A38l of the STG may be an important factor indicative of the effects of antipsychotic drugs, which can be potentially used to monitor drug effects for first-episode patients at an early stage in clinical practice.

Sex- and age-related changes in GABA signaling components in the human cortex

Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the nervous system. Previous studies have shown fluctuations in expression levels of GABA signaling components-glutamic acid decarboxylase (GAD), GABA receptor (GABAR) subunit, and GABA transporter (GAT)-with increasing age and between sexes; however, this limited knowledge is highly based on animal models that produce inconsistent findings. This study is the first analysis of the age- and sex-specific changes of the GAD, GABAA/BR subunits, and GAT expression in the human primary sensory and motor cortices; superior (STG), middle (MTG), and inferior temporal gyrus (ITG); and cerebellum. Utilizing Western blotting, we found that the GABAergic system is relatively robust against sex and age-related differences in all brain regions examined. However, we observed several sex-dependent differences in GABAAR subunit expression in STG along with age-dependent GABAAR subunit and GAD level alteration. No significant age-related differences were found in α1, α2, α5, β3, and γ2 subunit expression in the STG. However, we found significantly higher GABAAR α3 subunit expression in the STG in young males compared to old males. We observed a significant sex-dependent difference in α1 subunit expression: males presenting significantly higher levels compared to women across all stages of life in STG. Older females showed significantly lower α2, α5, and β3 subunit expression compared to old males in the STG. These changes found in the STG might significantly influence GABAergic neurotransmission and lead to sex- and age-specific disease susceptibility and progression.

Atypical audiovisual temporal function in autism and schizophrenia: similar phenotype, different cause

Binding across sensory modalities yields substantial perceptual benefits, including enhanced speech intelligibility. The coincidence of sensory inputs across time is a fundamental cue for this integration process. Recent work has suggested that individuals with diagnoses of schizophrenia (SZ) and autism spectrum disorder (ASD) will characterize auditory and visual events as synchronous over larger temporal disparities than their neurotypical counterparts. Namely, these clinical populations possess an enlarged temporal binding window (TBW). Although patients with SZ and ASD share aspects of their symptomatology, phenotypic similarities may result from distinct etiologies. To examine similarities and variances in audiovisual temporal function in these two populations, individuals diagnosed with ASD (n = 46; controls n = 40) and SZ (n = 16, controls = 16) completed an audiovisual simultaneity judgment task. In addition to standard psychometric analyses, synchrony judgments were assessed using Bayesian causal inference modeling. This approach permits distinguishing between distinct causes of an enlarged TBW: an a priori bias to bind sensory information and poor fidelity in the sensory representation. Findings indicate that both ASD and SZ populations show deficits in multisensory temporal acuity. Importantly, results suggest that while the wider TBWs in ASD most prominently results from atypical priors, the wider TBWs in SZ results from a trend toward changes in prior and weaknesses in the sensory representations. Results are discussed in light of current ASD and SZ theories and highlight that different perceptual training paradigms focused on improving multisensory integration may be most effective in these two clinical populations and emphasize that similar phenotypes may emanate from distinct mechanistic causes.

Structural and functional brain abnormalities in drug-naive, first-episode, and chronic patients with schizophrenia: a multimodal MRI study

BACKGROUND

Structural and functional brain abnormalities in schizophrenia (SZ) have been widely reported. However, a few studies have investigated both structural and functional characteristics in SZ patients at different stages to understand the neuropathology of SZ.

METHODS

In this study, we recruited 44 first-episode drug-naive SZ (FESZ) patients, 44 medicated chronic SZ (CSZ) patients, and 56 normal controls (NCs) and acquired their structural and resting-state functional magnetic resonance imaging (MRI). We then made group comparisons on structural and functional characteristics, including regional gray matter volume (GMV), regional homogeneity, amplitude of low-frequency fluctuation, and degree centrality. A linear support vector machine (SVM) combined with a recursive feature elimination (RFE) algorithm was implemented to discriminate three groups.

RESULTS

Our results indicated that the regional GMV was significantly decreased in patients compared with that in NCs; CSZ patients have more diffused GMV decreases primarily involved in the frontal and temporal lobes when compared with FESZ patients. Both FESZ and CSZ patients showed significant functional alterations compared with NCs; when compared with FESZ patients, CSZ patients showed significant reductions in functional characteristics in several brain regions associated with auditory, visual processing, and sensorimotor functions. Moreover, a linear SVM combined with a RFE algorithm was implemented to discriminate three groups. The accuracies of the three classifiers were 79.80%, 83.16%, and 81.71%, respectively. The performance of classifiers in this study with multimodal MRI was better than that of previous discriminative analyses of SZ patients with single-modal MRI.

CONCLUSION

Our findings bring new insights into the understanding of the neuropathology of SZ and contribute to stage-specific biomarkers in diagnosis and interventions of SZ.

Whole brain volume changes and its correlation with clinical symptom severity in patients with schizophrenia: A DARTEL-based VBM study

The purpose of this study was to evaluate gray matter (GM) and white matter (WM) volume alterations in whole-brain structures in patients with schizophrenia and healthy controls using voxel-based morphometry (VBM), and further to assess the correlation between GM and WM volume variations and symptom severity in schizophrenia. A total of 22 patients with schizophrenia and 22 age-matched healthy controls participated. Magnetic resonance image data were processed using SPM8 software with diffeomorphic anatomical registration via an exponentiated Lie algebra (DARTEL) algorithm. Patients with schizophrenia exhibited significantly decreased GM volumes of the insula, superior temporal gyrus (STG), gyrus rectus, and anterior cingulate cortex (ACC) compared with healthy controls. The GM volumes of the STG and gyrus rectus were negatively correlated with the positive scales on the Positive and Negative Syndrome Scale (PANSS) and those of the STG and ACC were negatively correlated with the negative scales. The durations of illness in schizophrenia were negatively correlated with the GM volumes of the insula, STG, and ACC. Patients with schizophrenia exhibited significantly decreased WM volumes of the superior frontal gyrus, inferior temporal gyrus, and STG. The WM volumes of the STG were negatively correlated with the duration of illness. Our findings suggest that GM and WM volume abnormalities in the STG are associated with the psychopathology of schizophrenia.

The associations between multisensory temporal processing and symptoms of schizophrenia

Recent neurobiological accounts of schizophrenia have included an emphasis on changes in sensory processing. These sensory and perceptual deficits can have a cascading effect onto higher-level cognitive processes and clinical symptoms. One form of sensory dysfunction that has been consistently observed in schizophrenia is altered temporal processing. In this study, we investigated temporal processing within and across the auditory and visual modalities in individuals with schizophrenia (SCZ) and age-matched healthy controls. Individuals with SCZ showed auditory and visual temporal processing abnormalities, as well as multisensory temporal processing dysfunction that extended beyond that attributable to unisensory processing dysfunction. Most importantly, these multisensory temporal deficits were associated with the severity of hallucinations. This link between atypical multisensory temporal perception and clinical symptomatology suggests that clinical symptoms of schizophrenia may be at least partly a result of cascading effects from (multi)sensory disturbances. These results are discussed in terms of underlying neural bases and the possible implications for remediation.

Neuroanatomical Abnormalities in Violent Individuals with and without a Diagnosis of Schizophrenia

Several structural brain abnormalities have been associated with aggression in patients with schizophrenia. However, little is known about shared and distinct abnormalities underlying aggression in these subjects and non-psychotic violent individuals. We applied a region-of-interest volumetric analysis of the amygdala, hippocampus, and thalamus bilaterally, as well as whole brain and ventricular volumes to investigate violent (n = 37) and non-violent chronic patients (n = 26) with schizophrenia, non-psychotic violent (n = 24) as well as healthy control subjects (n = 24). Shared and distinct volumetric abnormalities were probed by analysis of variance with the factors violence (non-violent versus violent) and diagnosis (non-psychotic versus psychotic), adjusted for substance abuse, age, academic achievement and negative psychotic symptoms. Patients showed elevated vCSF volume, smaller left hippocampus and smaller left thalamus volumes. This was particularly the case for non-violent individuals diagnosed with schizophrenia. Furthermore, patients had reduction in right thalamus size. With regard to left amygdala, we found an interaction between violence and diagnosis. More specifically, we report a double dissociation with smaller amygdala size linked to violence in non-psychotic individuals, while for psychotic patients smaller size was linked to non-violence. Importantly, the double dissociation appeared to be mostly driven by substance abuse. Overall, we found widespread morphometric abnormalities in subcortical regions in schizophrenia. No evidence for shared volumetric abnormalities in individuals with a history of violence was found. Finally, left amygdala abnormalities in non-psychotic violent individuals were largely accounted for by substance abuse. This might be an indication that the association between amygdala reduction and violence is mediated by substance abuse. Our results indicate the importance of structural abnormalities in aggressive individuals.

Conceptualization and treatment of negative symptoms in schizophrenia

Negative symptoms of schizophrenia including social withdrawal, diminished affective response, lack of interest, poor social drive, and decreased sense of purpose or goal directed activity predict poor functional outcomes for patients with schizophrenia. They may develop and be maintained as a result of structural and functional brain abnormalities, particularly associated with dopamine reward pathways and by environmental and psychosocial factors such as self-defeating cognitions and the relief from overstimulation that accompanies withdrawal from social and role functioning. Negative symptoms are more difficult to treat than the positive symptoms of schizophrenia and represent an unmet therapeutic need for large numbers of patients with schizophrenia. While antipsychotic medications to treat the symptoms of schizophrenia have been around for decades, they have done little to address the significant functional impairments in the disorder that are associated with negative symptoms. Negative symptoms and the resulting loss in productivity are responsible for much of the world-wide personal and economic burden of schizophrenia. Pharmacologic treatments may be somewhat successful in treating secondary causes of negative symptoms, such as antipsychotic side effects and depression. However, in the United States there are no currently approved treatments for severe and persistent negative symptoms (PNS) that are not responsive to treatments for secondary causes. Pharmacotherapy and psychosocial treatments are currently being developed and tested with severe and PNS as their primary targets. Academia, clinicians, the pharmaceutical industry, research funders, payers and regulators will need to work together to pursue novel treatments to address this major public health issue.

Neurobiological background of negative symptoms

Studies investigating neurobiological bases of negative symptoms of schizophrenia failed to provide consistent findings, possibly due to the heterogeneity of this psychopathological construct. We tried to review the findings published to date investigating neurobiological abnormalities after reducing the heterogeneity of the negative symptoms construct. The literature in electronic databases as well as citations and major articles are reviewed with respect to the phenomenology, pathology, genetics and neurobiology of schizophrenia. We searched PubMed with the keywords "negative symptoms," "deficit schizophrenia," "persistent negative symptoms," "neurotransmissions," "neuroimaging" and "genetic." Additional articles were identified by manually checking the reference lists of the relevant publications. Publications in English were considered, and unpublished studies, conference abstracts and poster presentations were not included. Structural and functional imaging studies addressed the issue of neurobiological background of negative symptoms from several perspectives (considering them as a unitary construct, focusing on primary and/or persistent negative symptoms and, more recently, clustering them into factors), but produced discrepant findings. The examined studies provided evidence suggesting that even primary and persistent negative symptoms include different psychopathological constructs, probably reflecting the dysfunction of different neurobiological substrates. Furthermore, they suggest that complex alterations in multiple neurotransmitter systems and genetic variants might influence the expression of negative symptoms in schizophrenia. On the whole, the reviewed findings, representing the distillation of a large body of disparate data, suggest that further deconstruction of negative symptomatology into more elementary components is needed to gain insight into underlying neurobiological mechanisms.

Structural correlates of formal thought disorder in schizophrenia: An ultra-high field multivariate morphometry study

BACKGROUND

Persistent formal thought disorder (FTD) is one of the most characteristic features of schizophrenia. Several neuroimaging studies report spatially distinct neuroanatomical changes in association with FTD. Given that most studies so far have employed a univariate localisation approach that obscures the study of covarying interregional relationships, the present study focussed on the multivariate systemic pattern of anatomical changes that contribute to FTD.

METHODS

Speech samples from nineteen medicated clinically stable schizophrenia patients and 20 healthy controls were evaluated for subtle formal thought disorder. Ultra high-field (7T) anatomical Magnetic Resonance Imaging scans were obtained from all subjects. Multivariate morphometric patterns were identified using an independent component approach (source based morphometry). Using multiple regression analysis, the morphometric patterns predicting positive and negative FTD scores were identified.

RESULTS

Morphometric variations in grey matter predicted a substantial portion of inter-individual variance in negative but not positive FTD. A pattern of concomitant striato-insular/precuneus reduction along with frontocingular grey matter increase had a significant association with negative FTD.

CONCLUSIONS

These results suggest that concomitant increase and decrease in grey matter occur in association with persistent negative thought disorder in clinically stable individuals with schizophrenia.

Neuropsychological and cerebral morphometric aspects of negative symptoms in schizophrenia: negative symptomatology is associated with specific mnestic deficits in schizophrenic patients

BACKGROUND

The prevalence of negative symptoms in schizophrenic patients seems to be an important indicator for treatment response and prognosis. Although negative symptoms have often been attributed to frontal lobe anomalies, neuropsychological and anatomical findings do not explicitly support this assumption. Since knowledge about the cerebral correlate of negative symptoms in schizophrenia might have a strong impact on therapeutic and psychopharmacological interventions, we aimed to answer this question by investigating the relationship between negative symptoms, neuropsychological functioning and cerebral volumes in schizophrenic patients.

METHODS

Twenty schizophrenic patients and 32 healthy controls were examined using a neuropsychological test battery for the assessment of temporal (mnestic) and frontal (executive) faculties. Volumetric measurements of temporal (hippocampus and amygdala) and frontal (orbitofrontal, dorsolateral prefrontal, and anterior cingulate area) brain areas were performed. Negative symptoms were assessed using the Scale for the Assessment of Negative Symptoms (SANS).

RESULTS

Schizophrenic patients performed worse than healthy controls in tests assessing verbal and visuospatial learning and memory functions and on the Stroop interference task. After dividing the schizophrenic group in patients with high and low SANS scores almost all of these deficits were restricted to the former group. There were no overall group differences regarding cerebral subarea volumes. Overall negative symptoms were significantly correlated with verbal memory functions but not with frontal lobe faculties.

CONCLUSIONS

Negative symptoms in schizophrenia could specifically associated with verbal memory deficits.

Automated parcellation of the brain surface generated from magnetic resonance images

We have developed a fast and reliable pipeline to automatically parcellate the cortical surface into sub-regions. The pipeline can be used to study brain changes associated with psychiatric and neurological disorders. First, a genus zero cortical surface for one hemisphere is generated from the magnetic resonance images at the parametric boundary of the white matter and the gray matter. Second, a hemisphere-specific surface atlas is registered to the cortical surface using geometry features mapped in the spherical domain. The deformation field is used to warp statistic labels from the atlas to the subject surface. The Dice index of the labeled surface area is used to evaluate the similarity between the automated labels with the manual labels on the subject. The average Dice across 24 regions on 14 testing subjects is 0.86. Alternative evaluations have also chosen to show the accuracy and flexibility of the present method. The point-wise accuracy of 14 testing subjects is above 86% in average. The experiment shows that the present method is highly consistent with FreeSurfer (>99% of the surface area), using the same set of labels.

Association of white matter deficits with clinical symptoms in antipsychotic-naive first-episode schizophrenia: an optimized VBM study using 3T

OBJECT

To examine the whole brain white matter morphology in antipsychotic-naive patients with first-episode schizophrenia (FES) and its correlations with symptom severity.

MATERIALS AND METHODS

High-resolution T1-weighted images of 64 drug-naive FES patients and 64 matched healthy controls were acquired using a 3 T MR imaging system. Then, optimized voxel-based morphometry was performed to compare the group differences. Finally, correlation analyses were conducted between the white matter volume (WMV) changes and clinical symptoms.

RESULTS

The FES showed significantly decreased WMV in the bilateral posterior limb of the internal capsule (PLIC) and right subgyral frontal white matter. The volume of the bilateral PLIC was negatively correlated with the Positive and Negative Syndrome Scale positive scores. Positive correlations were observed between all of the changed WMV measures and the Global Assessment of Functioning scores.

CONCLUSION

The current findings provide further evidence to support internal capsule and subgyral frontal white matter deficits at the early stage of schizophrenia that are potentially related to the core pathophysiology of the disease. Furthermore, these anatomical alterations were related to the clinical symptoms but not the untreated illness duration, suggesting that these deficits are related to aberrations in the neurodevelopmental process and may be relatively stable during the early course of schizophrenia.

Anatomical substrates of cognitive and clinical dimensions in first episode schizophrenia

OBJECTIVE

To explore gray (GM) and white matter (WM) abnormalities and the relationships with neuropsychopathology in first-episode schizophrenia (FES).

METHOD

Nineteen patients with first episode of non-affective psychosis and 18 controls underwent a magnetic resonance voxel-based morphometry. Additionally, WM fractional anisotropy (FA) was calculated. For correlative analysis, symptoms and neuropsychological performances were scored by PANSS and by a comprehensive neuropsychological assessment respectively.

RESULTS

Patients showed significantly decreased volume of left temporal lobe and disarray of all major WM tracts. Disorganized PANSS factor was inversely related to left cerebellar GM volume (corrected P = 0.03) and to WM FA of the left cerebellum, inferior fronto-occipital fasciculi (IFOF), and inferior longitudinal fasciculi (corrected P < 0.05). PANSS negative factor was inversely related to FA in the IFOF and superior longitudinal fasciculi (corrected P < 0.05). Impairment in facial emotion identification showed associations with temporo-occipital GM volume decrease (corrected P = 0.003) and WM disarray of superior and middle temporal gyri, anterior thalamic radiation, and superior longitudinal fasciculi (corrected P < 0.05). Speed of processing and visual memory correlated with WM abnormalities in fronto-temporal tracts.

CONCLUSION

These results confirm how the structural development of key brain regions is related to neuropsychopathological dysfunction in FES, consistently with a neurodevelopmentally derived misconnection syndrome.

Comparative study of regional homogeneity in schizophrenia and major depressive disorder

Compelling evidence suggests that there is a considerable overlap in structural and functional alternation in the brain between different neuropsychiatric disorders. However, whether these overlaps are specific for schizophrenia has yet to be investigated. A total of 36 patients with paranoid schizophrenia, 43 patients with major depressive disorder (MDD), and 44 healthy controls were recruited to undergo resting-state functional magnetic resonance imaging (rs-fMRI) for analysis of regional homogeneity (ReHo). Twelve regions of interest (ROIs) in the frontal and temporal lobes were generated and one-way ANOVA was performed to test the ReHo differences within these ROIs between the above three groups. The ReHo values within ROIs were extracted to investigate whether a left-right asymmetry existed in a mental disorder. One-way ANOVA showed significant differences in ReHo in the right superior frontal gyrus and left superior temporal gyrus; post hoc analysis revealed that schizophrenic patients had lower ReHo in the left superior temporal gyrus than either control subjects or patients with MDD. Increased ReHo was observed in the right superior frontal gyrus in schizophrenic patients compared with control subjects, and a left-less-than-right asymmetry was also found in this region in schizophrenic patients. The above alterations in ReHo were not affected by age and genders. Our study suggests that the altered ReHo in the superior frontal and temporal gyrus may be specific for schizophrenia rather than MDD. A left-less-than-right asymmetry activation pattern may exist in the resting-state superior frontal gyrus in schizophrenia. This finding would be helpful for better understanding the pathological mechanisms of schizophrenia.

Distinct structural alterations independently contributing to working memory deficits and symptomatology in paranoid schizophrenia

Schizophrenia is considered a brain disease with a quite heterogeneous clinical presentation. Studies in schizophrenia have yielded a wide array of correlations between structural and functional brain changes and clinical and cognitive symptoms. Reductions of grey matter volume (GMV) in the prefrontal and temporal cortex have been described which are crucial for the development of positive and negative symptoms and impaired working memory (WM). Associations between GMV reduction and positive and negative symptoms as well as WM impairment were assessed in schizophrenia patients (symptomatology in 34, WM in 26) and compared to healthy controls (36 total, WM in 26). GMV was determined by voxel-based morphometry and its relation to positive and negative symptoms as well as WM performance was assessed. In schizophrenia patients, reductions of GMV were evident in anterior cingulate cortex, ventrolateral prefrontal cortex (VLPFC), superior temporal cortex, and insula. GMV reductions in the superior temporal gyrus (STG) were associated with positive symptom severity as well as WM impairment. Furthermore, the absolute GMV of VLPFC was strongly related to negative symptoms. These predicted WM performance as well as processing speed. The present results support the assumption of two distinct pathomechanisms responsible for impaired WM in schizophrenia: (1) GMV reductions in the VLPFC predict the severity of negative symptoms. Increased negative symptoms in turn are associated with a slowing down of processing speed and predict an impaired WM. (2) GMV reductions in the temporal and mediofrontal cortex are involved in the development of positive symptoms and impair WM performance, too.

Association of schizophrenia in 22q11.2 deletion syndrome and gray matter volumetric deficits in the superior temporal gyrus

OBJECTIVE

Individuals with 22q11.2 deletion syndrome are known to be at high risk of developing schizophrenia. Previous imaging studies have provided limited data on the relation of schizophrenia expression in 22q11.2 deletion syndrome to specific regional brain volumetric changes. The authors hypothesized that the main structural brain finding associated with schizophrenia expression in 22q11.2 deletion syndrome, as for schizophrenia in the general population, would be gray matter volumetric deficits, especially in the temporal lobes.

METHOD

MR brain images from 29 patients with 22q11.2 deletion syndrome and schizophrenia and 34 comparison subjects with 22q11.2 deletion syndrome and no history of psychosis were analyzed using a voxel-based morphometry method that also yielded volumes for related region-of-interest analyses. The authors compared data from the two groups using an analysis of covariance model correcting for total intracranial volume, age, sex, IQ, and history of congenital cardiac defects. The false discovery rate threshold was set at 0.05 to account for multiple comparisons.

RESULTS

Voxel-based morphometry analyses identified significant gray matter reductions in the left superior temporal gyrus (Brodmann's area 22) in the schizophrenia group. There were no significant between-group differences in white matter or CSF volumes. Region-of-interest analyses showed significant bilateral gray matter volume reductions in the temporal lobes and superior temporal gyri in the schizophrenia group.

CONCLUSIONS

The structural brain expression of schizophrenia associated with the highly penetrant 22q11.2 deletion involves lower gray matter volumes in temporal lobe regions. These structural MRI findings in a 22q11.2 deletion syndrome form of schizophrenia are consistent with those from studies involving schizophrenia samples from the general population. The results provide further support for 22q11.2 deletion syndrome as a genetic subtype and as a useful neurodevelopmental model of schizophrenia.

Superior temporal gyrus volume in antipsychotic-naive people at risk of psychosis

BACKGROUND

Morphological abnormalities of the superior temporal gyrus have been consistently reported in schizophrenia, but the timing of their occurrence remains unclear.

AIMS

To determine whether individuals exhibit superior temporal gyral changes before the onset of psychosis.

METHOD

We used magnetic resonance imaging to examine grey matter volumes of the superior temporal gyrus and its subregions (planum polare, Heschl's gyrus, planum temporale, and rostral and caudal regions) in 97 antipsychotic-naive individuals at ultra-high risk of psychosis, of whom 31 subsequently developed psychosis and 66 did not, and 42 controls.

RESULTS

Those at risk of psychosis had significantly smaller superior temporal gyri at baseline compared with controls bilaterally, without any prominent subregional effect; however, there was no difference between those who did and did not subsequently develop psychosis.

CONCLUSIONS

Our findings indicate that grey matter reductions of the superior temporal gyrus are present before psychosis onset, and are not due to medication, but these baseline changes are not predictive of transition to psychosis.

Decreased density of serotonin 2A receptors in the superior temporal gyrus in schizophrenia--a postmortem study

The superior temporal gyrus (STG) is strongly implicated in the pathophysiology of schizophrenia, particularly with regards to auditory hallucinations. In this study, using in situ quantitative autoradiography in postmortem tissue, we investigated the binding of the [3H]ketanserin to 5-HT(2A) receptors and [3H]mesulergine to 5-HT(2C) receptors in the left STG of 8 male schizophrenic patients compared to 8 control subjects. A strong [3H]ketanserin binding was observed in the STG, however there was a very weak [3H]mesulergine binding in the STG. A significant decrease in binding of [(3)H]ketanserin was clearly observed in schizophrenia patients in comparison with control subjects. There were no significant correlations between 5-HT(2A) binding density and age, postmortem intervals, or brain pH. These results suggest that the alterations of the 5-HT(2A) receptors contribute to the pathophysiology of the STG in schizophrenia. Furthermore, there is a clear tendency for a positive correlation between 5-HT(2A) and muscarinic M1 receptor bindings, and for negative correlations between 5-HT(2A) and GABA(A) receptor bindings and between muscarinic M1 and GABA(A) receptor bindings. This provides a possible mechanism of auditory hallucinations through interactions between 5-HT(2A), acetylcholine muscarinic and GABA transmissions in the STG in schizophrenia.

Brain pathology in first-episode psychosis: magnetization transfer imaging provides additional information to MRI measurements of volume loss

Background

Loss of brain volume in first-episode psychosis can be detected using conventional magnetic resonance imaging (MRI), but subtle changes – not leading to reduction in volume – that may contribute to clinical and cognitive abnormalities, may go undetected. Magnetization transfer imaging (MTI), a technique more sensitive to subtle neuropathological changes than conventional MRI, could yield important information on the extent and nature of structural abnormalities.

Methods

Forty-eight patients (33 males) from a population-based sample with first-episode psychosis (41 with schizophrenia and 7 with schizoaffective psychosis) and 47 healthy volunteers (27 males) were studied. Differences in magnetization transfer ratio (MTR) and white and grey matter volumes between groups were investigated.

Results

In patients, MTR was reduced in right entorhinal cortex, fusiform, dentate and superior frontal gyri and in left superior frontal and inferior/rostral cingulate gyri. Grey matter volume was reduced in right insula, frontal operculum and middle and superior temporal gyri and in left middle temporal gyrus. Grey matter volume increases were seen in patients in the superior frontal gyrus. White matter volume loss was found adjacent to grey matter loss. In patients MTR was lower in all areas of volumetric differences between groups suggesting that both changes may be related. Similar findings were observed when patients with schizoaffective psychosis were removed from the analysis. The correlations between clinical and MRI parameters did not survive correction for multiple comparisons.

Conclusions

MTI frontal and temporal abnormalities suggesting neuroaxonal and myelin changes were more extensive in our patients than those detected with conventional MRI. Our findings also suggest that there is regional variation in the severity of structural brain abnormalities.

The relationship between symptom severity and regional cortical and grey matter volumes in schizophrenia

OBJECTIVE

To investigate the relationship between symptom severity and cortical and grey matter volumes in schizophrenia.

METHOD

Fifty-three outpatients with schizophrenia were assessed by the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms. Symptoms were grouped into five factors (negative, relational, inattention, disorganization, and reality distortion). Cortical and lobar grey matter volumes within all regions of the brain were obtained from magnetic resonance images using two independent software tools. The relationships between brain volumes and symptom factors were analyzed by partial correlations controlling for age, gender, dose and type of antipsychotic medication, and intracranial volume.

RESULTS

Negative symptoms were generally associated with larger cortical volumes in all regions of the brain, and the relational and inattention factors were associated with larger frontal grey matter volumes. The reality distortion factor was associated with smaller cortical volumes throughout the brain and with smaller frontal and temporal grey matter volumes.

CONCLUSION

Differential contribution of positive and negative symptoms to variation in cortical and grey matter volumes indicates separate neurobiological mechanisms underlying the two major symptom domains in schizophrenia.

Superior temporal gyrus volume change in schizophrenia: a review on region of interest volumetric studies

Imaging studies of schizophrenia (SCZ) have repeatedly demonstrated volume differences in superior temporal gyrus (STG) and its subregions. Among them, some studies employed the Region of Interest (ROI) method. We carried out a systematic review of the published literature on STG volumetry MRI studies to examine the potential of ROI method for identifying specific structural differences and correlations with clinical variables including hallucinations and thought disorder symptoms in SCZ. Forty-six studies were identified as suitable for review and analysis including 1444 patients with SCZ and 1327 controls. Female and left-handed subjects are under-represented in the literature and insight from sex and handedness differences may be lost. Thirty-five studies reported significant differences in STG or subregional volumes including bilateral or unilateral ROI, and volume reduction was the most common change in SCZ. Thirty studies reported correlations between volume changes and clinical symptoms or syndromes and 18 found positive results. Among them, left STG or subregions appear to be more involved in the generation of hallucinations and thought disorder than right side. The majority of five follow-up studies found evidence of progressive changes in volumes. Clinical heterogeneity, MRI acquisition parameters, anatomical landmarks for ROI, and sample characteristics, are likely to be the main factors leading to heterogeneous results. Clearly this research links pathophysiological changes in the STG with the development of hallucinations and thought disorder in patients with SCZ, especially in the left side. There is a suggestion that these changes may be progressive but this requires more thorough and comprehensive assessment.

Endophenotypes in schizophrenia: a selective review

BACKGROUND

Given the wealth of data in the literature on schizophrenia endophenotypes, it is useful to have one source to reference their frequency data. We reviewed the literature on disease-liability associated variants in structural and functional magnetic resonance images (MRI), sensory processing measures, neuromotor abilities, neuropsychological measures, and physical characteristics in schizophrenia patients (SCZ), their first-degree relatives (REL), and healthy controls (HC). The purpose of this review was to provide a summary of the existing data on the most extensively published endophenotypes for schizophrenia.

METHODS

We searched PubMed and MedLine for all studies on schizophrenia endophenotypes comparing SCZ to HC and/or REL to HC groups. Percent abnormal values, generally defined as >2 SD from the mean (in the direction of abnormality) and/or associated effect sizes (Cohen's d) were calculated for each study.

RESULTS

Combined, the articles reported an average 39.4% (SD=20.7%; range=2.2-100%) of abnormal values in SCZ, 28.1% (SD=16.6%; range=1.6-67.0%) abnormal values in REL, and 10.2% (SD=6.7%; range=0.0-34.6%) in HC groups.

CONCLUSIONS

These findings are reviewed in the context of emerging hypotheses on schizophrenia endophenotypes, as well as a discussion of clustering trends among the various intermediate phenotypes. In addition, programs for future research are discussed, as instantiated in a few recent large-scale studies on multiple endophenotypes across patients, relatives, and healthy controls.

Voxel-based structural magnetic resonance imaging (MRI) study of patients with early onset schizophrenia

BACKGROUND

Investigation into the whole brain morphology of early onset schizophrenia (EOS) to date has been sparse. We studied the regional brain volumes in EOS patients, and the correlations between regional volume measures and symptom severity.

METHODS

A total of 18 EOS patients (onset under 16 years) and 18 controls matched for age, gender, parental socioeconomic status, and height were examined. Voxel-based morphometric analysis using the Brain Analysis Morphological Mapping (BAMM) software package was employed to explore alterations of the regional grey (GM) and white matter (WM) volumes in EOS patients. Symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS).

RESULTS

EOS patients had significantly reduced GM volume in the left parahippocampal, inferior frontal, and superior temporal gyri, compared with the controls. They also had less WM volume in the left posterior limb of the internal capsule and the left inferior longitudinal fasciculus. The positive symptom score of PANSS (higher values corresponding to more severe symptoms) was negatively related to GM volume in the bilateral posterior cingulate gyrus. The negative symptom score was positively correlated with GM volume in the right thalamus. As for the association with WM volume, the positive symptom score of PANSS was positively related to cerebellar WM (vermis region), and negatively correlated with WM in the brain stem (pons) and in the bilateral cerebellum (hemisphere region).

CONCLUSION

Our findings of regional volume alterations of GM and WM in EOS patients coincide with those of previous studies of adult onset schizophrenia patients. However, in brain regions that had no overall structural differences between EOS patients and controls (that is, the bilateral posterior cingulate gyrus, the right thalamus, the cerebellum, and the pons), within-subject analysis of EOS patients alone revealed that there were significant associations of the volume in these areas and the symptom severity. These findings suggest that at an early stage of the illness, especially for those with onset before brain maturation, a wide range of disturbed neural circuits, including these brain regions that show no apparent morphological changes, may contribute to the formation of the symptomatology.

No changes in densities of cannabinoid receptors in the superior temporal gyrus in schizophrenia

OBJECTIVE

In recent years, abnormal changes in the endocannabinoid system have been found in schizophrenia. The superior temporal gyrus (STG) is strongly implicated in the pathophysiology of schizophrenia, particularly with regards to auditory hallucinations. In this study, we investigated the binding density of cannabinoid CB1 receptors in the STG of schizophrenia patients compared to control subjects.

METHODS

Quantitative autoradiography was used to investigate the binding densities of [(3)H]SR141716A (a selective antagonist) and [(3)H]CP-55940 (an agonist) to the CB1 receptors in the STG. Post-mortem brain tissue was obtained from the NSW Tissue Resource Centre (Australia).

RESULTS

Contrasting to previous findings in the alterations of CB1 receptor densities in the prefrontal, anterior and posterior cingulate cortex of schizophrenia, which were suggested to be associated to impairment of cognition function, no significant difference was found between the schizophrenia and control cases in both [(3)H]SR141716A and [(3)H]CP-55940 binding.

CONCLUSION

We suggest that CB1 receptors in the STG are not involved in the pathology of schizophrenia and the auditory hallucination symptom of this disease.

Cerebral Disconnectivity: An Early Event in Schizophrenia

Neuroimaging and electrophysiological investigations have demonstrated numerous differences in brain morphology and function of chronic schizophrenia patients compared to healthy controls. Studying patients at the beginning of their disease without the confounding effects of chronicity, medication, and institutionalization may provide a better understanding of schizophrenia. Recently, at many institutions around the world, special projects have been launched for specialized treatment and research of this interesting patient group. Using the PubMed search engine in this update, the authors summarize recent investigations between January 2002 and September 2006 that focus on whether signs of disconnectivity already exist early in the disease process. They discuss gray and white matter changes, their impact on symptomatology, electroencephalogram-based studies on connectivity, and possible influences of medication. NEUROSCIENTIST 14(1):19—45, 2008. DOI: 10.1177/1073858406298391

Reduced thalamic volume in first-episode non-affective psychosis: correlations with clinical variables, symptomatology and cognitive functioning

Structural studies have inconsistently shown the presence of thalamic volume differences in patients with schizophrenia. However, only a few studies have examined the relation between thalamic structure and clinical and cognitive variables in early phases of the illness. Thalamic volumes in right-handed minimally treated first episode patients with non-affective psychosis (N=61) relative to those of right-handed healthy comparison subjects (N=40) were measured. Thalamic volumes in the right and left hemispheres and total thalamic volume were automatically segmented and analyzed using BRAINS2. Analysis of covariance was used to control for intracranial volume. Clinical symptoms were assessed by total scores of BPRS, SAPS and SANS. The relationship between three cognitive dimensions (verbal learning and memory, speed processing/executive functioning and sustained attention/vigilance), and thalamic volume was evaluated. The impact of the duration of untreated illness, untreated psychosis and prodrome period in thalamic morphometry was also explored. Right, left, and total thalamic volumes of the patients with non-affective psychosis were significantly smaller than those of the healthy subjects. Larger thalamic volumes were associated with an earlier age of onset, a poorer cognitive functioning and a more severe negative symptomatology. Thalamic volumetric differences between patients with non-affective psychosis and healthy controls are already present at early phases of the illness. However, further investigations are warranted to fully clarify the relationship between those structural anomalies and clinical and cognitive outcomes.

Positive symptoms and duration of illness predict functional laterality and attention modulation in schizophrenia

OBJECTIVE

Dichotic listening (DL) performance in schizophrenia, reflecting hemispheric asymmetry and the functional integrity of the left temporal lobe, can vary with clinical characteristics. Previous studies have not taken the co-linearity of clinical variables into account. The aim of the present study was to evaluate the roles of positive symptoms and duration of illness in DL through Structural Equation Modeling (SEM), thus allowing for complex relationships between the variables.

METHOD

We pooled patients from four previous DL studies to create a heterogeneous group of 129 schizophrenic patients, all tested with a consonant-vowel syllables DL procedure that included attentional instructions.

RESULTS

A model where positive symptoms predicted a laterality component and duration of illness predicted an attention component in DL was confirmed.

CONCLUSION

Positive symptoms predicted reduced functional laterality, suggesting involvement of left temporal lobe language processing. Duration of illness predicted impaired attention modulation, possibly reflecting the involvement of frontotemporal networks.

Increased density of GABAA receptors in the superior temporal gyrus in schizophrenia

The superior temporal gyrus (STG) is strongly implicated in the pathophysiology of schizophrenia, particularly with regards to auditory hallucinations. In a previous study we reported a decrease in the density of M1 and M2/M4 muscarinic receptors in the STG in schizophrenia. In this study, we investigated the density of GABA(A) receptors in the left STG of schizophrenia patients compared to control subjects. We used quantitative autoradiography to investigate the binding of the agonist [(3)H] muscimol to GABA(A )receptors in the STG. A significantly higher density of [(3)H] muscimol binding was observed in the upper three quarters of the STG grey matter (corresponding to layers I-IV) than in the lower one-quarter (layers V-VI) in both groups. A significant increase (about 30%, P<0.05) in binding of [(3)H] muscimol was clearly observed in schizophrenia patients compared to control subjects. There were no significant correlations between [(3)H] muscimol binding density and age, post-mortem interval, brain pH or final recorded antipsychotic drug use. These results suggest an increase of GABA(A) receptor densities in the STG of schizophrenia patients.

Grey matter deficits and symptom profile in first episode schizophrenia

Several studies have investigated grey matter reductions in first episode schizophrenia (FES), but few have examined the relationship between grey matter reduction and clinical profile. A group of 31 patients with strictly defined FES and 30 healthy controls underwent T1-weighted magnetic resonance imaging (MRI) scan. Voxel-based morphometry in SPM99 was used to identify four distinct regions of grey matter reduction in the FES subjects. The regions of interest (ROIs) were in the left ventral prefrontal cortex (ROI 1), left parietal and temporal cortices (ROI 2), right cerebellum (ROI 3), and right frontal and parietal cortices (ROI 4). These regions of reduction were transformed into binary masks, which were convolved with patients' pre-processed grey matter images. Patients' grey matter volumes in these regions were correlated with their composite scores on the following three symptom dimensions: Psychomotor Poverty, Disorganization and Reality Distortion. The volumes of ROIs 1, 2 and 4 were found to be significantly correlated with the Reality Distortion syndrome score. Our findings indicate that distinct, widespread grey matter reductions are present very early in the course of schizophrenia. The results also suggest a possible structural underpinning for the abnormal brain activity typically associated with symptoms of Reality Distortion.

Differential contributions of prefrontal and temporolimbic pathology to mechanisms of psychosis

Common abnormalities within the schizophrenia spectrum may be essential for the pathogenesis of schizophrenia, but additional pathological changes may be required for the development of full-blown schizophrenia. Clarifying the neurobiological similarities and differences between established schizophrenia and a milder form of schizophrenia spectrum disorder would potentially discriminate the pathophysiological mechanisms underlying the core features of the schizophrenia spectrum from those associated with overt psychosis. High-resolution MRIs were acquired from 25 patients with schizotypal disorder, 53 patients with schizophrenia and 59 healthy volunteers matched for age, gender, handedness and parental education. Volumetric measurements of the medial temporal structures and the prefrontal cortex subcomponents were performed using consecutive 1-mm thick coronal slices. Parcellation of the prefrontal cortex into subcomponents was performed according to the intrinsic anatomical landmarks of the frontal sulci/gyri. Compared with the controls, the bilateral volumes of the amygdala and the hippocampus were reduced comparably in the schizotypal and schizophrenia patients. The parahippocampal gyrus volume did not differ significantly between diagnostic groups. Total prefrontal grey matter volumes were smaller bilaterally in the schizophrenia patients than in the controls and the schizotypal patients, whereas the schizotypal patients had larger prefrontal grey matter than the controls in the right hemisphere. In the schizophrenia patients, grey matter volumes of the bilateral superior frontal gyrus, left middle frontal gyrus, bilateral inferior frontal gyrus and bilateral straight gyrus were smaller than those in the controls. The schizophrenia patients also had reduced grey matter volumes in the right superior frontal gyrus, bilateral middle frontal gyrus and right inferior frontal gyrus relative to the schizotypal patients. Compared with the controls, the schizotypal patients had larger volumes of the bilateral middle frontal gyrus and smaller volumes of the right straight gyrus. There were no significant between-group differences in volumes of the ventral medial prefrontal cortex or the orbitofrontal cortex. These findings suggest that volume reductions in the amygdala and hippocampus are the common morphological substrates for the schizophrenia spectrum, which presumably represent the vulnerability. Additional widespread involvement of the prefrontal cortex in schizophrenia may lead to the loss of inhibitory control in other brain regions and suggests (although it is not specifically be related to) its critical role in the manifestation of overt psychosis.