Temporal lobe gray matter in schizophrenia spectrum: a volumetric MRI study of the fusiform gyrus, parahippocampal gyrus, and middle and inferior temporal gyri

Abnormal connectivity and activation during audiovisual speech perception in schizophrenia

The unconscious integration of vocal and facial cues during speech perception facilitates face-to-face communication. Recent studies have provided substantial behavioural evidence concerning impairments in audiovisual (AV) speech perception in schizophrenia. However, the specific neurophysiological mechanism underlying these deficits remains unknown. Here, we investigated activities and connectivities centered on the auditory cortex during AV speech perception in schizophrenia. Using magnetoencephalography, we recorded and analysed event-related fields in response to auditory (A: voice), visual (V: face) and AV (voice-face) stimuli in 23 schizophrenia patients (13 males) and 22 healthy controls (13 males). The functional connectivity associated with the subadditive response to AV stimulus (i.e., [AV] < [A] + [V]) was also compared between the two groups. Within the healthy control group, [AV] activity was smaller than the sum of [A] and [V] at latencies of approximately 100 ms in the posterior ramus of the lateral sulcus in only the left hemisphere, demonstrating a subadditive N1m effect. Conversely, the schizophrenia group did not show such a subadditive response. Furthermore, weaker functional connectivity from the posterior ramus of the lateral sulcus of the left hemisphere to the fusiform gyrus of the right hemisphere was observed in schizophrenia. Notably, this weakened connectivity was associated with the severity of negative symptoms. These results demonstrate abnormalities in connectivity between speech- and face-related cortical areas in schizophrenia. This aberrant subadditive response and connectivity deficits for integrating speech and facial information may be the neural basis of social communication dysfunctions in schizophrenia.

Brain Hemispheric Asymmetry in Schizophrenia and Bipolar Disorder

BACKGROUND

This study aimed to compare brain asymmetry in patients with schizophrenia (SCZ), bipolar disorder (BPD), and healthy controls to test whether asymmetry patterns could discriminate and set boundaries between two partially overlapping severe mental disorders.

METHODS

We applied a fully automated voxel-based morphometry (VBM) approach to assess structural brain hemispheric asymmetry in magnetic resonance imaging (MRI) anatomical scans in 60 participants (SCZ = 20; BP = 20; healthy controls = 20), all right-handed and matched for gender, age, and education.

RESULTS

Significant differences in gray matter asymmetry were found between patients with SCZ and BPD, between SCZ patients and healthy controls (HC), and between BPD patients and HC. We found a higher asymmetry index (AI) in BPD patients when compared to SCZ in Brodmann areas 6, 11, and 37 and anterior cingulate cortex and an AI higher in SCZ patients when compared to BPD in the cerebellum.

CONCLUSION

Our study found significant differences in brain asymmetry between patients with SCZ and BPD. These promising results could be translated to clinical practice, given that structural brain changes detected by MRI are good candidates for exploration as biological markers for differential diagnosis, besides helping to understand disease-specific abnormalities.

Resting-State EEG Connectivity at High-Frequency Bands and Attentional Performance Dysfunction in Stabilized Schizophrenia Patients

Background and Objectives: Attentional dysfunction has long been viewed as one of the fundamental underlying cognitive deficits in schizophrenia. There is an urgent need to understand its neural underpinning and develop effective treatments. In the process of attention, neural oscillation has a central role in filtering information and allocating resources to either stimulus-driven or goal-relevant objects. Here, we asked if resting-state EEG connectivity correlated with attentional performance in schizophrenia patients. Materials and Methods: Resting-state EEG recordings were obtained from 72 stabilized patients with schizophrenia. Lagged phase synchronization (LPS) was used to measure whole-brain source-based functional connectivity between 84 intra-cortical current sources determined by eLORETA (exact low-resolution brain electromagnetic tomography) for five frequencies. The Conners' Continuous Performance Test-II (CPT-II) was administered for evaluating attentional performance. Linear regression with a non-parametric permutation randomization procedure was used to examine the correlations between the whole-brain functional connectivity and the CPT-II measures. Results: Greater beta-band right hemispheric fusiform gyrus (FG)-lingual gyrus (LG) functional connectivity predicted higher CPT-II variability scores (r = 0.44, p < 0.05, corrected), accounting for 19.5% of variance in the CPT-II VAR score. Greater gamma-band right hemispheric functional connectivity between the cuneus (Cu) and transverse temporal gyrus (TTG) and between Cu and the superior temporal gyrus (STG) predicted higher CPT-II hit reaction time (HRT) scores (both r = 0.50, p < 0.05, corrected), accounting for 24.6% and 25.1% of variance in the CPT-II HRT score, respectively. Greater gamma-band right hemispheric Cu-TTG functional connectivity predicted higher CPT-II HRT standard error (HRTSE) scores (r = 0.54, p < 0.05, corrected), accounting for 28.7% of variance in the CPT-II HRTSE score. Conclusions: Our study indicated that increased right hemispheric resting-state EEG functional connectivity at high frequencies was correlated with poorer focused attention in schizophrenia patients. If replicated, novel approaches to modulate these networks may yield selective, potent interventions for improving attention deficits in schizophrenia.

A significant, functional and replicable risk KTN1 variant block for schizophrenia

Cortical and subcortical structural alteration has been extensively reported in schizophrenia, including the unusual expansion of gray matter volumes (GMVs) of basal ganglia (BG), especially putamen. Previous genome-wide association studies pinpointed kinectin 1 gene (KTN1) as the most significant gene regulating the GMV of putamen. In this study, the role of KTN1 variants in risk and pathogenesis of schizophrenia was explored. A dense set of SNPs (n = 849) covering entire KTN1 was analyzed in three independent European- or African-American samples (n = 6704) and one mixed European and Asian Psychiatric Genomics Consortium sample (n = 56,418 cases vs. 78,818 controls), to identify replicable SNP-schizophrenia associations. The regulatory effects of schizophrenia-associated variants on the KTN1 mRNA expression in 16 cortical or subcortical regions in two European cohorts (n = 138 and 210, respectively), the total intracranial volume (ICV) in 46 European cohorts (n = 18,713), the GMVs of seven subcortical structures in 50 European cohorts (n = 38,258), and the surface areas (SA) and thickness (TH) of whole cortex and 34 cortical regions in 50 European cohorts (n = 33,992) and eight non-European cohorts (n = 2944) were carefully explored. We found that across entire KTN1, only 26 SNPs within the same block (r2 > 0.85) were associated with schizophrenia across ≥ 2 independent samples (7.5 × 10-5 ≤ p ≤ 0.048). The schizophrenia-risk alleles, which increased significantly risk for schizophrenia in Europeans (q < 0.05), were all minor alleles (f < 0.5), consistently increased (1) the KTN1 mRNA expression in 12 brain regions significantly (5.9 × 10-12 ≤ p ≤ 0.050; q < 0.05), (2) the ICV significantly (6.1 × 10-4 ≤ p ≤ 0.008; q < 0.05), (3) the SA of whole (9.6 × 10-3 ≤ p ≤ 0.047) and two regional cortices potentially (2.5 × 10-3 ≤ p ≤ 0.042; q > 0.05), and (4) the TH of eight regional cortices potentially (0.006 ≤ p ≤ 0.050; q > 0.05), and consistently decreased (1) the BG GMVs significantly (1.8 × 10-19 ≤ p ≤ 0.050; q < 0.05), especially putamen GMV (1.8 × 10-19 ≤ p ≤ 1.0 × 10-4; q < 0.05, (2) the SA of four regional cortices potentially (0.010 ≤ p ≤ 0.048), and (3) the TH of four regional cortices potentially (0.015 ≤ p ≤ 0.049) in Europeans. We concluded that we identified a significant, functional, and robust risk variant block covering entire KTN1 that might play a critical role in the risk and pathogenesis of schizophrenia.

Functional connectivity and gray matter deficits within the auditory attention circuit in first-episode psychosis

Background

Selective attention deficits in first episode of psychosis (FEP) can be indexed by impaired attentional modulation of auditory M100. It is unknown if the pathophysiology underlying this deficit is restricted to auditory cortex or involves a distributed attention network. We examined the auditory attention network in FEP.

Methods

MEG was recorded from 27 FEP and 31 matched healthy controls (HC) while alternately ignoring or attending tones. A whole-brain analysis of MEG source activity during auditory M100 identified non-auditory areas with increased activity. Time-frequency activity and phase-amplitude coupling were examined in auditory cortex to identify the attentional executive carrier frequency. Attention networks were defined by phase-locking at the carrier frequency. Spectral and gray matter deficits in the identified circuits were examined in FEP.

Results

Attention-related activity was identified in prefrontal and parietal regions, markedly in precuneus. Theta power and phase coupling to gamma amplitude increased with attention in left primary auditory cortex. Two unilateral attention networks were identified with precuneus seeds in HC. Network synchrony was impaired in FEP. Gray matter thickness was reduced within the left hemisphere network in FEP but did not correlate with synchrony.

Conclusion

Several extra-auditory attention areas with attention-related activity were identified. Theta was the carrier frequency for attentional modulation in auditory cortex. Left and right hemisphere attention networks were identified, with bilateral functional deficits and left hemisphere structural deficits, though FEP showed intact auditory cortex theta phase-gamma amplitude coupling. These novel findings indicate attention-related circuitopathy early in psychosis potentially amenable to future non-invasive interventions.

Clinical and cortical similarities identified between bipolar disorder I and schizophrenia: A multivariate approach

BACKGROUND

Structural neuroimaging studies have identified similarities in the brains of individuals diagnosed with schizophrenia (SZ) and bipolar I disorder (BP), with overlap in regions of gray matter (GM) deficits between the two disorders. Recent studies have also shown that the symptom phenotypes associated with SZ and BP may allow for a more precise categorization than the current diagnostic criteria. In this study, we sought to identify GM alterations that were unique to each disorder and whether those alterations were also related to unique symptom profiles.

MATERIALS AND METHODS

We analyzed the GM patterns and clinical symptom presentations using independent component analysis (ICA), hierarchical clustering, and n-way biclustering in a large (N ∼ 3,000), merged dataset of neuroimaging data from healthy volunteers (HV), and individuals with either SZ or BP.

RESULTS

Component A showed a SZ and BP < HV GM pattern in the bilateral insula and cingulate gyrus. Component B showed a SZ and BP < HV GM pattern in the cerebellum and vermis. There were no significant differences between diagnostic groups in these components. Component C showed a SZ < HV and BP GM pattern bilaterally in the temporal poles. Hierarchical clustering of the PANSS scores and the ICA components did not yield new subgroups. N-way biclustering identified three unique subgroups of individuals within the sample that mapped onto different combinations of ICA components and symptom profiles categorized by the PANSS but no distinct diagnostic group differences.

CONCLUSION

These multivariate results show that diagnostic boundaries are not clearly related to structural differences or distinct symptom profiles. Our findings add support that (1) BP tend to have less severe symptom profiles when compared to SZ on the PANSS without a clear distinction, and (2) all the gray matter alterations follow the pattern of SZ < BP < HV without a clear distinction between SZ and BP.

Frontotemporal thalamic connectivity in schizophrenia and schizotypal personality disorder

Schizotypal personality disorder (SPD) resembles schizophrenia, but with attenuated brain abnormalities and the absence of psychosis. The thalamus is integral for processing and transmitting information across cortical regions and widely implicated in the neurobiology of schizophrenia. Comparing thalamic connectivity in SPD and schizophrenia could reveal an intermediate schizophrenia-spectrum phenotype to elucidate neurobiological risk and protective factors in psychosis. We used rsfMRI to investigate functional connectivity between the mediodorsal nucleus (MDN) and pulvinar, and their connectivity with frontal and temporal cortical regions, respectively in 43 healthy controls (HCs), and individuals in the schizophrenia-spectrum including 45 psychotropic drug-free individuals with SPD, and 20 individuals with schizophrenia-related disorders [(schizophrenia (n = 10), schizoaffective disorder (n = 8), schizophreniform disorder (n = 1) and psychosis NOS (n = 1)]. Individuals with SPD had greater functional connectivity between the MDN and pulvinar compared to individuals with schizophrenia. Thalamo-frontal (i.e., between the MDN and rostral middle frontal cortex) connectivity was comparable in SPD and HCs; in SPD greater connectivity was associated with less symptom severity. Individuals with schizophrenia had less thalamo-frontal connectivity and thalamo-temporal (i.e., pulvinar to the transverse temporal cortex) connectivity compared with HCs. Thalamo-frontal functional connectivity may be comparable in SPD and HCs, but abnormal in schizophrenia, and that this may be protective against psychosis in SPD.

A Latent Gaussian Copula Model for Mixed Data Analysis in Brain Imaging Genetics

Recent advances in imaging genetics make it possible to combine different types of data including medical images like functional magnetic resonance imaging (fMRI) and genetic data like single nucleotide polymorphisms (SNPs) for comprehensive diagnosis of mental disorders. Understanding complex interactions among these heterogeneous data may give rise to a new perspective, while at the same time demand statistical models for their integration. Various graphical models have been proposed for the study of interaction or association networks with continuous, binary, and count data as well as the mixture of them. However, limited efforts have been made for the multinomial case, for instance, SNP data. Our goal is therefore to fill the void by developing a graphical model for the integration of fMRI image and SNP data, which can provide deeper understanding of the unknown neurogenetic mechanism. In this article, we propose a latent Gaussian copula model for mixed data containing multinomial components. We assume that the discrete variable is obtained by discretizing a latent (unobserved) continuous variable and then create a semi-rank based estimator of the graph structure. The simulation results demonstrate that the proposed latent correlation has more steady and accurate performance than several existing methods in detecting graph structure. When applying to a real schizophrenia data consisting of SNP array and fMRI image collected by the Mind Clinical Imaging Consortium (MCIC), the proposed method reveals a set of distinct SNP-brain associations, which are verified to be biologically significant. The proposed model is statistically promising in handling mixed types of data including multinomial components, which can find widespread applications. To promote reproducible research, the R code is available at https://github.com/Aiying0512/LGCM.

Association of Structural Magnetic Resonance Imaging Measures With Psychosis Onset in Individuals at Clinical High Risk for Developing Psychosis: An ENIGMA Working Group Mega-analysis

Importance

The ENIGMA clinical high risk (CHR) for psychosis initiative, the largest pooled neuroimaging sample of individuals at CHR to date, aims to discover robust neurobiological markers of psychosis risk.

Objective

To investigate baseline structural neuroimaging differences between individuals at CHR and healthy controls as well as between participants at CHR who later developed a psychotic disorder (CHR-PS+) and those who did not (CHR-PS-).

Design, Setting, and Participants

In this case-control study, baseline T1-weighted magnetic resonance imaging (MRI) data were pooled from 31 international sites participating in the ENIGMA Clinical High Risk for Psychosis Working Group. CHR status was assessed using the Comprehensive Assessment of At-Risk Mental States or Structured Interview for Prodromal Syndromes. MRI scans were processed using harmonized protocols and analyzed within a mega-analysis and meta-analysis framework from January to October 2020.

Main Outcomes and Measures

Measures of regional cortical thickness (CT), surface area, and subcortical volumes were extracted from T1-weighted MRI scans. Independent variables were group (CHR group vs control group) and conversion status (CHR-PS+ group vs CHR-PS- group vs control group).

Results

Of the 3169 included participants, 1428 (45.1%) were female, and the mean (SD; range) age was 21.1 (4.9; 9.5-39.9) years. This study included 1792 individuals at CHR and 1377 healthy controls. Using longitudinal clinical information, 253 in the CHR-PS+ group, 1234 in the CHR-PS- group, and 305 at CHR without follow-up data were identified. Compared with healthy controls, individuals at CHR exhibited widespread lower CT measures (mean [range] Cohen d = -0.13 [-0.17 to -0.09]), but not surface area or subcortical volume. Lower CT measures in the fusiform, superior temporal, and paracentral regions were associated with psychosis conversion (mean Cohen d = -0.22; 95% CI, -0.35 to 0.10). Among healthy controls, compared with those in the CHR-PS+ group, age showed a stronger negative association with left fusiform CT measures (F = 9.8; P < .001; q < .001) and left paracentral CT measures (F = 5.9; P = .005; q = .02). Effect sizes representing lower CT associated with psychosis conversion resembled patterns of CT differences observed in ENIGMA studies of schizophrenia (ρ = 0.35; 95% CI, 0.12 to 0.55; P = .004) and individuals with 22q11.2 microdeletion syndrome and a psychotic disorder diagnosis (ρ = 0.43; 95% CI, 0.20 to 0.61; P = .001).

Conclusions and Relevance

This study provides evidence for widespread subtle, lower CT measures in individuals at CHR. The pattern of CT measure differences in those in the CHR-PS+ group was similar to those reported in other large-scale investigations of psychosis. Additionally, a subset of these regions displayed abnormal age associations. Widespread disruptions in CT coupled with abnormal age associations in those at CHR may point to disruptions in postnatal brain developmental processes.

Reduced Cortical Thickness in Schizophrenia and Schizotypal Disorder

Schizotypal disorder is characterized by odd behavior and attenuated forms of schizophrenic features without the manifestation of overt and sustained psychoses. Past studies suggest that schizotypal disorder shares biological and psychological commonalties with schizophrenia. Structural magnetic resonance imaging (MRI) studies have demonstrated both common and distinct regional gray matter changes between schizophrenia and schizotypal disorder. However, no study has compared cortical thickness, which is thought to be a specific indicator of cortical atrophy, between schizophrenia and schizotypal disorder. The subjects consisted of 102 schizophrenia and 46 schizotypal disorder patients who met the International Classification of Diseases, 10th edition criteria and 79 gender- and age-matched healthy controls. Each participant underwent a T1-weighted 3-D MRI scan using a 1.5-Tesla scanner. Cortical thickness was estimated using FreeSurfer. Consistent with previous studies, schizophrenia patients exhibited wide-spread cortical thinning predominantly in the frontal and temporal regions as compared with healthy subjects. Patients with schizotypal disorder had a significantly reduced cortical thickness in the left fusiform and parahippocampal gyri, right medial superior frontal gyrus, right inferior frontal gyrus, and right medial orbitofrontal cortex as compared with healthy controls. Schizophrenia patients had thinner cortices in the left precentral and paracentral gyri than those with schizotypal disorder. Common cortical thinning patterns observed in schizophrenia and schizotypal disorder patients may be associated with vulnerability to psychosis. Our results also suggest that distinct cortical changes in schizophrenia and schizotypal disorder may be associated with the differences in the manifestation of clinical symptoms among these disorders.

Neutral face and complex object neurophysiological processing deficits in long-term schizophrenia and in first hospitalized schizophrenia-spectrum individuals

BACKGROUND

Face processing is impaired in long-term schizophrenia as indexed by a reduced face-related N170 event-related potential (ERP) that corresponds with volumetric decreases in right fusiform gyrus. Impairment in face processing may constitute an object-specific deficit in schizophrenia that relates to social impairment and misattribution of social signs in the disease, or the face deficit may be part of a more general deficit in complex visual processing. Further, it is not clear the degree to which face and complex object processing deficits are present early in disease course. To that end, the current study investigated face- and object-elicited N170 in long-term schizophrenia and the first hospitalized schizophrenia-spectrum.

METHODS

ERPs were collected from 32 long-term schizophrenia patients and 32 matched controls, and from 31 first hospitalization patients and 31 matched controls. Subjects detected rarely presented butterflies among non-target neutral faces and automobiles.

RESULTS

For both patient groups, the N170s to all stimuli were significantly attenuated. Despite this overall reduction, the increase in N170 amplitude to faces was intact in both patient samples. Symptoms were not correlated with N170 amplitude or latency to faces.

CONCLUSIONS

Information processing of complex stimuli is fundamentally impaired in schizophrenia, as reflected in attenuated N170 ERPs in both first hospitalized and long-term patients. This suggests the presence of low-level visual complex object processing deficits near disease onset that persist with disease course.

Variation in fourteen brain structure volumes in schizophrenia: A comprehensive meta-analysis of 246 studies

Despite hundreds of structural MRI studies documenting smaller brain volumes on average in schizophrenia compared to controls, little attention has been paid to group differences in the variability of brain volumes. Examination of variability may help interpret mean group differences in brain volumes and aid in better understanding the heterogeneity of schizophrenia. Variability in 246 MRI studies was meta-analyzed for 13 structures that have shown medium to large mean effect sizes (Cohen's d≥0.4): intracranial volume, total brain volume, lateral ventricles, third ventricle, total gray matter, frontal gray matter, prefrontal gray matter, temporal gray matter, superior temporal gyrus gray matter, planum temporale, hippocampus, fusiform gyrus, insula; and a control structure, caudate nucleus. No significant differences in variability in cortical/subcortical volumes were detected in schizophrenia relative to controls. In contrast, increased variability was found in schizophrenia compared to controls for intracranial and especially lateral and third ventricle volumes. These findings highlight the need for more attention to ventricles and detailed analyses of brain volume distributions to better elucidate the pathophysiology of schizophrenia.

Brain morphologic changes in early stages of psychosis: Implications for clinical application and early intervention

To date, a large number of magnetic resonance imaging (MRI) studies have been conducted in schizophrenia, which generally demonstrate gray matter reduction, predominantly in the frontal and temporo-limbic regions, as well as gross brain abnormalities (e.g., a deviated sulcogyral pattern). Although the causes as well as timing and course of these findings remain elusive, these morphologic changes (especially gross brain abnormalities and medial temporal lobe atrophy) are likely present at illness onset, possibly reflecting early neurodevelopmental abnormalities. In addition, longitudinal MRI studies suggest that patients with schizophrenia and related psychoses also have progressive gray matter reduction during the transition period from prodrome to overt psychosis, as well as initial periods after psychosis onset, while such changes may become almost stable in the chronic stage. These active brain changes during the early phases seem to be relevant to the development of clinical symptoms in a region-specific manner (e.g., superior temporal gyrus atrophy and positive psychotic symptoms), but may be at least partly ameliorated by antipsychotic medication. Recently, increasing evidence from MRI findings in individuals at risk for developing psychosis has suggested that those who subsequently develop psychosis have baseline brain changes, which could be at least partly predictive of later transition into psychosis. In this article, we selectively review previous MRI findings during the course of psychosis and also refer to the possible clinical applicability of these neuroimaging research findings, especially in the diagnosis of schizophrenia and early intervention for psychosis.

Frontal and temporal cortical volume, white matter tract integrity, and hemispheric asymmetry in schizotypal personality disorder

Abnormalities in temporal and frontal cortical volume, white matter tract integrity, and hemispheric asymmetry have been implicated in schizophrenia-spectrum disorders. Schizotypal personality disorder can provide insight into vulnerability and protective factors in these disorders without the confounds associated with chronic psychosis. However, multimodal imaging and asymmetry studies in SPD are sparse. Thirty-seven individuals with SPD and 29 healthy controls (HC) received clinical interviews and 3T magnetic resonance T1-weighted and diffusion tensor imaging scans. Mixed ANOVAs were performed on gray matter volumes of the lateral temporal regions involved in auditory and language processing and dorsolateral prefrontal cortex involved in executive functioning, as well as fractional anisotropy (FA) of prominent white matter tracts that connect frontal and temporal lobes. In the temporal lobe regions, there were no group differences in volume, but SPD had reduced right>left middle temporal gyrus volume asymmetry compared to HC and lacked the right>left asymmetry in the inferior temporal gyrus volume seen in HC. In the frontal regions, there were no differences between groups on volume or asymmetry. In the white matter tracts, SPD had reduced FA in the left sagittal stratum and superior longitudinal fasciculus, and increased right>left asymmetry in sagittal stratum FA compared to HC. In the SPD group, lower left superior longitudinal fasciculus FA was associated with greater severity of disorganization symptoms. Findings suggest that abnormities in structure and asymmetry of temporal regions and frontotemporal white matter tract integrity are implicated in SPD pathology.

Meta-analysis reveals a lack of sexual dimorphism in human amygdala volume

The amygdala plays a key role in many affective behaviors and psychiatric disorders that differ between men and women. To test whether human amygdala volume (AV) differs reliably between the sexes, we performed a systematic review and meta-analysis of AVs reported in MRI studies of age-matched healthy male and female groups. Using four search strategies, we identified 46 total studies (58 matched samples) from which we extracted effect sizes for the sex difference in AV. All data were converted to Hedges g values and pooled effect sizes were calculated using a random-effects model. Each dataset was further meta-regressed against study year and average participant age. We found that uncorrected amygdala volume is about 10% larger in males, with pooled sex difference effect sizes of g=0.581 for right amygdala (κ=28, n=2022), 0.666 for left amygdala (κ=28, n=2006), and 0.876 for bilateral amygdala (κ=16, n=1585) volumes (all p values < 0.001). However, this difference is comparable to the sex differences in intracranial volume (ICV; g=1.186, p<.001, 11.9% larger in males, κ=11) and total brain volume (TBV; g=1.278, p<0.001, 11.5% larger in males, κ=15) reported in subsets of the same studies, suggesting the sex difference in AV is a product of larger brain size in males. Among studies reporting AVs normalized for ICV or TBV, sex difference effect sizes were small and not statistically significant: g=0.171 for the right amygdala (p=0.206, κ=13, n=1560); 0.233 for the left amygdala (p=0.092, κ=12, n=1512); and 0.257 for bilateral volume (p=0.131, κ=5, n=1629). These values correspond to less than 0.1% larger corrected right AV and 2.5% larger corrected left AV in males compared to females. In summary, AV is not selectively enhanced in human males, as often claimed. Although we cannot rule out subtle male-female group differences, it is not accurate to refer to the human amygdala as "sexually dimorphic."

Characterization of the Fiber Connectivity Profile of the Cerebral Cortex in Schizotypal Personality Disorder: A Pilot Study

Schizotypal personality disorder (SPD) is considered one of the classic disconnection syndromes. However, the specific cortical disconnectivity pattern has not been fully investigated. In this study, we aimed to explore significant alterations in whole-cortex structural connectivity in SPD individuals (SPDs) by combining the techniques of brain surface morphometry and white matter tractography. Diffusion and structural MR data were collected from 20 subjects with SPD (all males; age, 19.7 ± 0.9 years) and 18 healthy controls (all males; age, 20.3 ± 1.0 years). To measure the structural connectivity for a given unit area of the cortex, the fiber connectivity density (FiCD) value was proposed and calculated as the sum of the fractional anisotropy of all the fibers connecting to that unit area in tractography. Then, the resultant whole-cortex FiCD maps were compared in a vertex-wise manner between SPDs and controls. Compared with normal controls, SPDs showed significantly decreased FiCD in the rostral middle frontal gyrus (crossing BA 9 and BA 10) and significantly increased FiCD in the anterior part of the fusiform/inferior temporal cortex (P < 0.05, Monte Carlo simulation corrected). Moreover, the gray matter volume extracted from the left rostral middle frontal cluster was observed to be significantly greater in the SPD group (P = 0.02). Overall, this study identifies a decrease in connectivity in the left middle frontal cortex as a key neural deficit at the whole-cortex level in SPD, thus providing insight into its neuropathological basis.

Quantitative Measurements in the Human Hippocampus and Related Areas: Correspondence between Ex-Vivo MRI and Histological Preparations

The decrease of volume estimates in different structures of the medial temporal lobe related to memory correlate with the decline of cognitive functions in neurodegenerative diseases. This study presents data on the association between MRI quantitative parameters of medial temporal lobe structures and their quantitative estimate in microscopic examination. Twelve control cases had ex-vivo MRI, and thereafter, the temporal lobe of both hemispheres was sectioned from the pole as far as the level of the splenium of the corpus callosum. Nissl stain was used to establish anatomical boundaries between structures in the medial temporal lobe. The study included morphometrical and stereological estimates of the amygdaloid complex, hippocampus, and temporal horn of the lateral ventricle, as well as different regions of grey and white matter in the temporal lobe. Data showed a close association between morphometric MRI images values and those based on the histological determination of boundaries. Only values in perimeter and circularity of the piamater were different. This correspondence is also revealed by the stereological study, although irregular compartments resulted in a lesser agreement. Neither age (< 65 yr and > 65 yr) nor hemisphere had any effect. Our results indicate that ex-vivo MRI is highly associated with quantitative information gathered by histological examination, and these data could be used as structural MRI biomarker in neurodegenerative diseases.

Schizotypal personality disorder

Early phenomenological descriptions of schizophrenia have acknowledged the existence of milder schizophrenia spectrum disorders characterized by the presence of attenuated symptoms typically present in chronic schizophrenia. The investigation of the schizophrenia spectrum disorders offers an opportunity to elucidate the pathophysiological mechanisms giving rise to schizophrenia. Differences and similarities between subjects with schizotypal personality disorder (SPD), the prototypical schizophrenia personality disorder, and chronic schizophrenia have been investigated with genetic, neurochemical, imaging, and pharmacological techniques. Patients with SPD and the more severely ill patients with chronic schizophrenia share cognitive, social, and attentional deficits hypothesized to result from common neurodevelopmentally based cortical temporal and prefrontal pathology. However, these deficits are milder in SPD patients due to their capacity to recruit other related brain regions to compensate for dysfunctional areas. Individuals with SPD are also less vulnerable to psychosis due to the presence of protective factors mitigating subcortical DA hyperactivity. Given the documented close relationship to other schizophrenic disorders, SPD will be included in the psychosis section of DSM-5 as a schizophrenia spectrum disorder as well as in the personality disorder section.

White matter deficits in first episode schizophrenia: an activation likelihood estimation meta-analysis

BACKGROUND

Diffusion tensor imaging (DTI) has been widely used in psychiatric research and has provided evidence of white matter abnormalities in first episode schizophrenia (FES). The goal of the present meta-analysis was to identify white matter deficits by DTI in FES.

METHODS

A systematic search was conducted to collect DTI studies with voxel-wised analysis of the fractional anisotropy (FA) in FES. The coordinates of regions with FA changes were meta-analyzed using the activation likelihood estimation (ALE) method which weighs each study on the basis of its sample size.

RESULTS

A total of 8 primary studies were selected, including 271 FES patients and 297 healthy controls. Among these studies, 52 regions showed reductions in the FA in FES while 2 regions had increased FA. Consistent FA reductions in the white matter of the right deep frontal and left deep temporal lobes were identified in all FES patients relative to healthy controls. Fiber tracking showed that the main tracts involved were the cingulum bundle, the left inferior longitudinal fasciculus, the left inferior fronto-occipital fasciculus and the interhemispheric fibers running through the corpus callosum.

CONCLUSIONS

The current findings provide evidence confirming the lack of connection in the fronto-limbic circuitry at the early stages of the schizophrenia. Because the coordinates reported in the primary literature were highly variable, future investigations with large samples would be required to support the identified white matter changes in FES.

Neuroimaging findings in schizotypal personality disorder: a systematic review

BACKGROUND

Schizotypal personality disorder is the prototypical schizophrenia-spectrum condition, sharing similar phenomenological, cognitive, genetic, physiological, neurochemical, neuroanatomical and neurofunctional abnormalities with schizophrenia. Investigations into SPD circumvent many confounds inherent to schizophrenia such as medication and institutionalization. Hence, SPD offers a unique vantage point from which to study schizophrenia-spectrum conditions.

METHODS

We systematically reviewed the neuroimaging literature in SPD to establish: (1) whether there are concordant findings in SPD and schizophrenia, possibly reflective of core pathology between the two conditions and (2) whether there are discordant findings in SPD and schizophrenia, possibly reflecting protective factors in the former. The findings are synthesized across structural and functional neuroimaging domains.

RESULTS

A total of 54 studies were identified. Medial temporal lobe structures seem to be compromised in both SPD and schizophrenia. In schizophrenia prefrontal structures are further compromised, whereas in SPD these seem to be larger-than-normal, possibly reflecting a compensatory mechanism. Additional pathology is discussed, including evidence of aberrant subcortical dopaminergic functioning.

CONCLUSIONS

SPD is a schizophrenia-spectrum condition that shares pathology with schizophrenia, but is distinct in showing unique neural findings. Future studies are needed to confirm and localize regions of common and disparate pathology between SPD and schizophrenia.

Automatic statistical shape analysis of cerebral asymmetry in 3D T1-weighted magnetic resonance images at vertex-level: application to neuroleptic-naïve schizophrenia

The study of the structural asymmetries in the human brain can assist the early diagnosis and progression of various neuropsychiatric disorders, and give insights into the biological bases of several cognitive deficits. The high inter-subject variability in cortical morphology complicates the detection of abnormal asymmetries especially if only small samples are available. This work introduces a novel automatic method for the local (vertex-level) statistical shape analysis of gross cerebral hemispheric surface asymmetries which is robust to the individual cortical variations. After segmentation of the cerebral hemispheric volumes from three-dimensional (3D) T1-weighted magnetic resonance images (MRI) and their spatial normalization to a common space, the right hemispheric masks were reflected to match with the left ones. Cerebral hemispheric surfaces were extracted using a deformable model-based algorithm which extracted the salient morphological features while establishing the point correspondence between the surfaces. The interhemispheric asymmetry, quantified by customized measures of asymmetry, was evaluated in a few thousands of corresponding surface vertices and tested for statistical significance. The developed method was tested on scans obtained from a small sample of healthy volunteers and first-episode neuroleptic-naïve schizophrenics. A significant main effect of the disease on the local interhemispheric asymmetry was observed, both in females and males, at the frontal and temporal lobes, the latter being often linked to the cognitive, auditory, and memory deficits in schizophrenia. The findings of this study, although need further testing in larger samples, partially replicate previous studies supporting the hypothesis of schizophrenia as a neurodevelopmental disorder.

Neuroimaging studies in schizophrenia: an overview of research from Asia

Neuroimaging studies in schizophrenia help clarify the neural substrates underlying the pathogenesis of this neuropsychiatric disorder. Contemporary brain imaging in schizophrenia is predominated by magnetic resonance imaging (MRI)-based research approaches. This review focuses on the various imaging studies from India and their relevance to the understanding of brain abnormalities in schizophrenia. The existing studies are predominantly comprised of structural MRI reports involving region-of-interest and voxel-based morphometry approaches, magnetic resonance spectroscopy and single-photon emission computed tomography/positron emission tomography (SPECT/PET) studies. Most of these studies are significant in that they have evaluated antipsychotic-naïve schizophrenia patients--a relatively difficult population to obtain in contemporary research. Findings of these studies offer robust support to the existence of significant brain abnormalities at very early stages of the disorder. In addition, theoretically relevant relationships between these brain abnormalities and developmental aberrations suggest possible neurodevelopmental basis for these brain deficits.

Patients with Schizophrenia Fail to Up-Regulate Task-Positive and Down-Regulate Task-Negative Brain Networks: An fMRI Study Using an ICA Analysis Approach

Recent research suggests that the cerebral correlates of cognitive deficits in schizophrenia are nested in the activity of widespread, inter-regional networks rather than being restricted to any specific brain location. One of the networks that have received focus lately is the default mode network. Parts of this network have been reported as hyper-activated in schizophrenia patients (SZ) during rest and during task performance compared to healthy controls (HC), although other parts have been found to be hypo-activated. In contrast to this network, task-positive networks have been reported as hypo-activated compared in SZ during task performance. However, the results are mixed, with, e.g., the dorsolateral prefrontal cortex showing both hyper- and hypo-activation in SZ. In this study we were interested in signal increase and decrease differences between a group of SZ and HC in cortical networks, assuming that the regulatory dynamics of alternating task-positive and task-negative neuronal processes are aberrant in SZ. We compared 31 SZ to age- and gender-matched HC, and used fMRI and independent component analysis (ICA) in order to identify relevant networks. We selected the independent components (ICs) with the largest signal intensity increases (STG, insula, supplementary motor cortex, anterior cingulate cortex, and MTG) and decreases (fusiform gyri, occipital lobe, PFC, cingulate, precuneus, and angular gyrus) in response to a dichotic auditory cognitive task. These ICs were then tested for group differences. Our findings showed deficient up-regulation of the executive network and a corresponding deficit in the down-regulation of the anterior default mode, or effort network during task performance in SZ when compared with HC. These findings may indicate a deficit in the dynamics of alternating task-dependent and task-independent neuronal processes in SZ. The results may cast new light on the mechanisms underlying cognitive deficits in schizophrenia, and may be of relevance for diagnostics and new treatments.

Entorhinal Cortex Volume in Antipsychotic-naïve Schizophrenia

BACKGROUND

Entorhinal cortex (ERC), a multimodal sensory relay station for the hippocampus, is critically involved in learning, emotion, and novelty detection. One of the pathogenetic mechanistic bases in schizophrenia is proposed to involve aberrant information processing in the ERC. Several studies have looked at cytoarchitectural and morphometric changes in the ERC, but results have been inconsistent possibly due to the potential confounding effects of antipsychotic treatment.

MATERIALS AND METHODS

In this study, we have examined the entorhinal cortex volume in antipsychotic-naïve schizophrenia patients (n=40; M:F=22:18) in comparison with age, sex, and handedness, matched (as a group) with healthy subjects (n=42; M:F=25:17) using a valid method. 3-Tesla MR images with 1-mm sections were used and the data was analyzed using the SPSS software.

RESULTS

Female schizophrenia patients (1.25±0.22 mL) showed significant volume deficit in the right ERC in comparison with female healthy controls (1.45±0.34 mL) (F=4.9; P=0.03), after controlling for the potential confounding effects of intracranial volume. However, male patients did not differ from male controls. The left ERC volume did not differ between patients and controls.

CONCLUSIONS

Consistent with the findings of a few earlier studies we found a reduction in the right ERC volume in patients. However, this was limited to women. Contextually, our study finding supports the role for ERC deficit in schizophrenia pathogenesis - perhaps mediated through aberrant novelty detection. Sex-differential observation of ERC volume deficit in schizophrenia needs further studies.

A review of structural MRI and diffusion tensor imaging in schizotypal personality disorder

Individuals with schizotypal personality disorder (SPD) share genetic, phenomenologic, and cognitive abnormalities with people diagnosed with schizophrenia. To date, 15 structural MRI studies of the brain have examined size, and 3 diffusion tensor imaging studies have examined white matter connectivity in SPD. Overall, both types of structural neuroimaging modalities have shown temporal lobe abnormalities similar to those observed in schizophrenia, while frontal lobe regions appear to show more sparing. This intriguing pattern suggests that frontal lobe sparing may suppress psychosis, which is consistent with the idea of a possible neuroprotective factor. In this paper, we review these 18 studies and discuss whether individuals with SPD who both resemble and differ from schizophrenia patients in their phenomenology, share some or all of the structural brain imaging characteristics of schizophrenia. We attempt to group the MRI abnormalities in SPD into three patterns: 1) a spectrum of severity-abnormalities are similar to those observed in schizophrenia but not so severe; 2) a spectrum of region-abnormalities affecting some, but not all, brain regions affected in schizophrenia; and 3) a spectrum of compensation-abnormalities reflecting greater-than-normal white matter volume, possibly serving as a buffer or compensatory mechanism protecting the individual with SPD from the frank psychosis observed in schizophrenia.

A follow-up MRI study of the fusiform gyrus and middle and inferior temporal gyri in schizophrenia spectrum

While longitudinal magnetic resonance imaging (MRI) studies have demonstrated progressive gray matter reduction of the superior temporal gyrus (STG) during the early phases of schizophrenia, it remains largely unknown whether other temporal lobe structures also exhibit similar progressive changes and whether these changes, if present, are specific to schizophrenia among the spectrum disorders. In this longitudinal MRI study, the gray matter volumes of the fusiform, middle temporal, and inferior temporal gyri were measured at baseline and follow-up scans (mean inter-scan interval=2.7 years) in 18 patients with first-episode schizophrenia, 13 patients with schizotypal disorder, and 20 healthy controls. Both schizophrenia and schizotypal patients had a smaller fusiform gyrus than controls bilaterally at both time points, whereas no group difference was found in the middle and inferior temporal gyri. In the longitudinal comparison, the schizophrenia patients showed significant fusiform gyrus reduction (left, -2.6%/year; right, -2.3%/year) compared with schizotypal patients (left: -0.4%/year; right: -0.2%/year) and controls (left: 0.1%/year; right: 0.0%/year). However, the middle and inferior temporal gyri did not exhibit significant progressive gray matter change in all diagnostic groups. In the schizophrenia patients, a higher cumulative dose of antipsychotics during follow-up was significantly correlated with less severe gray matter reduction in the left fusiform gyrus. The annual gray matter loss of the fusiform gyrus did not correlate with that of the STG previously reported in the same subjects. Our findings suggest regional specificity of the progressive gray matter reduction in the temporal lobe structures, which might be specific to overt schizophrenia within the schizophrenia spectrum.

Are we studying and treating schizophrenia correctly?

New findings are rapidly revealing an increasingly detailed image of neural- and molecular-level dysfunction in schizophrenia, distributed throughout interconnected cortico-striato-pallido-thalamic circuitry. Some disturbances appear to reflect failures of early brain maturation, that become codified into dysfunctional circuit properties, resulting in a substantial loss of, or failure to develop, both cells and/or appropriate connectivity across widely dispersed brain regions. These circuit disturbances are variable across individuals with schizophrenia, perhaps reflecting the interaction of multiple different risk genes and epigenetic events. Given these complex and variable hard-wired circuit disturbances, it is worth considering how new and emerging findings can be integrated into actionable treatment models. This paper suggests that future efforts towards developing more effective therapeutic approaches for the schizophrenias should diverge from prevailing models in genetics and molecular neuroscience, and focus instead on a more practical three-part treatment strategy: 1) systematic rehabilitative psychotherapies designed to engage healthy neural systems to compensate for and replace dysfunctional higher circuit elements, used in concert with 2) medications that specifically target cognitive mechanisms engaged by these rehabilitative psychotherapies, and 3) antipsychotic medications that target nodal or convergent circuit points within the limbic-motor interface, to constrain the scope and severity of psychotic exacerbations and thereby facilitate engagement in cognitive rehabilitation. The use of targeted cognitive rehabilitative psychotherapy plus synergistic medication has both common sense and time-tested efficacy with numerous other neuropsychiatric disorders.

Hippocampal volume reduction in first-episode and chronic schizophrenia: a review and meta-analysis

Several magnetic resonance imaging studies have reported hippocampal volume reduction in patients with schizophrenia, but other studies have reported contrasting results. In this review and meta-analysis, the authors aim to clarify whether a reduction in hippocampal volume characterizes patients with schizophrenia by considering illness phase (chronic and first episode) and hippocampus side separately. They made a detailed literature search for studies reporting physical volumetric hippocampal measures of patients with schizophrenia and healthy control (HC) participants and found 44 studies that were eligible for meta-analysis. Individual meta-analyses were also performed on 13 studies of first-episode patients and on 22 studies of chronic patients. The authors also detected any different findings when only males or both males and females were considered. Finally, additional meta-analyses and analyses of variance investigated the role of the factors "illness phase" and "side" on hippocampal volume reduction. Overall, the patient group showed significant bilateral hippocampal volume reduction compared with HC. Interestingly, first-episode and chronic patients showed same-size hippocampal volume reduction. Moreover, the left hippocampus was smaller than the right hippocampus in patients and HC. This review and meta-analysis raises the question about whether hippocampal volume reduction in schizophrenia is of neurodevelopmental origin. Future studies should specifically investigate this issue.

Cingulate and temporal lobe fractional anisotropy in schizotypal personality disorder

BACKGROUND

Consistent with the clinical picture of milder symptomatology in schizotypal personality disorder (SPD) than schizophrenia, morphological studies indicate SPD abnormalities in temporal lobe regions but to a much lesser extent in prefrontal regions implicated in schizophrenia. Lower fractional anisotropy (FA), a measure of white-matter integrity within prefrontal, temporal, and cingulate regions has been reported in schizophrenia but has been little studied in SPD.

AIMS

The study aim was to examine temporal and prefrontal white matter FA in 30 neuroleptic-naïve SPD patients and 35 matched healthy controls (HCs). We hypothesized that compared with HCs, SPD patients would exhibit lower FA in temporal lobe and anterior cingulum regions but relative sparing in prefrontal regions.

METHOD

We acquired diffusion tensor imaging (DTI) in all participants and examined FA in the white matter underlying Brodmann areas (BAs) in dorsolateral prefrontal (BAs 44, 45, and 46), temporal lobe (BAs 22, 21, and 20), and cingulum (BAs 25, 24, 31, 23, and 29) regions with a series of analyses using multivariate analysis of variance.

RESULTS

Compared with HCs, the SPD group had significantly lower FA in the left temporal lobe but not prefrontal regions. In the cingulum, FA was lower in the SPD group in the posterior regions (BAs 31 and 23), higher in the anterior (BA 25) regions and lower overall in the right but not the left cingulum. Among the SPD group, lower FA in the cingulum was associated with more severe negative symptoms (e.g., odd speech).

CONCLUSIONS

Similar to schizophrenia, our results indicate cingulum-temporal lobe FA abnormalities in SPD and suggest that cingulum abnormalities are associated with negative symptoms.

Effect of cytomegalovirus infection on temporal lobe development in utero: quantitative MRI studies

Several environmental factors, including viral infections during fetal development, are known to increase the risk of schizophrenia. Cytomegalovirus (CMV) is the main cause of viral congenital infection. Since changes in temporal lobe structures are a consistent finding in imaging studies of adult schizophrenics, we investigated possible derangement in temporal lobe development in CMV infected fetuses. Abdominal MRI (1.5 T) was performed using a single-shot fast spin echo T2-weighted sequence. MRI volumetry was employed to measure brain and temporal lobe size in 27 CMV infected fetuses and 52 gestational age matched controls in utero. The ratio of temporal lobe to whole brain was computed for each fetus and group comparisons were performed using Student's t-test or ANOVA. Temporal lobe volumes, normalized to whole brain and co-varied with gestational age; were significantly smaller in fetuses infected with CMV compared to uninfected fetuses. (Infected group mean ± SEM: 0.086 ± 0.006, controls: 0.113 ± 0.003, p<0.0001). Infection during the 1st and 2nd trimester had a more pronounced effect than infection during the 3rd trimester. Infected fetuses with no MRI findings had significantly lower temporal lobe/whole brain ratios than controls (0.092 ± 0.008, p<0.01, N=11) and the lowest ratios were observed in fetuses with overt findings such as cysts or gray matter heterotopy (0.067 ± 0.015). These results demonstrate the ability of quantitative fetal brain MRI to detect previously unreported, specific deficits in brain development in CMV infected fetuses, which, in conjunction with other genetic and environmental factors, may contribute to the risk of developing schizophrenia later in life.

Impaired modulation of attention and emotion in schizophrenia

OBJECTIVE

Fronto-limbic interactions facilitate the generation of task-relevant responses while inhibiting interference from emotionally distracting information. Schizophrenia is associated with deficits in both executive attention and affective regulation. This study aims to elucidate the neural correlates of emotion-attention regulation and shifting in schizophrenia.

METHOD

We employed functional magnetic resonance imaging to probe the fronto-limbic regions in 16 adults with schizophrenia and 13 matched adults with no history of psychiatric illness. Subjects performed a forced-choice visual oddball task where they detected infrequent target circles embedded in a series of infrequent nontarget aversive and neutral pictures and frequent squares.

RESULTS

In control participants, target events activated a dorsal frontoparietal network, whereas these regions were deactivated by aversive stimuli. Conversely, ventral frontolimbic brain regions were activated by aversive stimuli and deactivated by target events. In the patient group, regional hemodynamic timecourses revealed not only reduced activation to target and aversive events in dorsal executive and ventral limbic regions, respectively, but also reduced deactivation to target and aversive stimuli in ventral and dorsal regions, respectively, relative to the control group. Patients further showed reduced spatial extent of activation in the right inferior frontal gyrus during the target and aversive conditions. Activation of the anterior cingulate to aversive images was inversely related to severity of avolition and anhedonia symptoms in the schizophrenia group.

CONCLUSIONS

These results suggest both frontal and limbic dysfunction in schizophrenia as well as aberrant reciprocal inhibitions between these regions during attention-emotion modulation in this disorder.

Reduced laterality as a trait marker of schizophrenia--evidence from structural and functional neuroimaging

Laterality is a characteristic principle of the organization of the brain systems for language, and reduced hemispheric asymmetry has been considered a risk factor for schizophrenia. Here we sought support for the risk factor hypothesis by investigating whether reduced asymmetry of temporal lobe structure and function is also present in unaffected relatives. Sixteen schizophrenia patients, 16 age-matched first-degree relatives, and 15 healthy controls underwent high-resolution three-dimensional anatomical imaging and functional magnetic resonance imaging during auditory stimulation. Both the overall auditory cortex and planum temporale volumes and the lateralization to the left hemisphere were markedly reduced in patients. The decrease of lateralization correlated with increased severity of symptoms. In addition, both the overall functional activation in response to auditory stimulation and its asymmetry were reduced in the patients. Relatives had intermediate values between patients and controls on both structural and functional measures. This study provides added support for the idea that reduced hemispheric asymmetry is a biological risk factor for schizophrenia.

A selective review of volumetric and morphometric imaging in schizophrenia

Brain imaging studies have long supported that schizophrenia is a disorder of the brain, involving many discrete and widely spread regions. Generally, studies have shown decreases in cortical gray matter (GM) volume. Here, we selectively review recent papers studying GM volume changes in schizophrenia subjects, both first-episode (FE) and chronic, in an attempt to quantify and better understand differences between healthy and patient groups. We focused on the cortical GM of the prefrontal cortex, limbic and paralimbic structures, temporal lobe, and one subcortical structure (the caudate nucleus). We performed a search of the electronic journal database PsycINFO using the keywords "schizophrenia" and "MRI," and selected for papers published between 2001 and 2008. We then screened for only those studies utilizing manual or manually edited tracing methodologies for determining regions of interest (ROIs). Each region of interest was indexed independently; thus, one paper might yield results for numerous brain regions. Our review found that in almost all ROIs, cortical GM volume was decreased in the patient populations. The only exception was the caudate nucleus - most studies reviewed showed no change, while one study showed an increase in volume; this region, however, is particularly sensitive to medication effects. The reductions were seen in both FE and chronic schizophrenia. These results clearly support that schizophrenia is an anatomical disorder of the brain, and specifically that schizophrenia patients tend to have decreased cortical GM in regions involved in higher cognition and emotional processing. That these reductions were found in both FE and chronic subjects supports that brain abnormalities are present at the onset of illness, and are not simply a consequence of chronicity. Additional studies assessing morphometry at different phases of the illness, including prodromal stages, together with longitudinal studies will elucidate further the role of progression in this disorder.

Encoding deficit during face processing within the right fusiform face area in schizophrenia

Face processing is crucial to social interaction, but is impaired in schizophrenia patients, who experience delays in face recognition, difficulties identifying others, and misperceptions of affective content. The right fusiform face area plays an important role in the early stages of human face processing and thus may be affected in schizophrenia. The aim of the study was therefore to investigate whether face processing deficits are related to dysfunctions of the right fusiform face area in schizophrenia patients compared with controls. In a rapid, event-related functional magnetic resonance imaging (fMRI) design, we investigated the encoding of new faces, as well as the recognition of newly learned, famous, and unfamiliar faces, in 13 schizophrenia patients and 21 healthy controls. We applied region of interest analysis to each individual's right fusiform face area and tested for group differences. Controls displayed higher blood oxygenation level dependent (BOLD) activation during the memorization of faces that were later successfully recognized. In schizophrenia patients, this effect was not observed. During the recognition task, schizophrenia patients exhibited lower BOLD responses, less accuracy, and longer reaction times to famous and unfamiliar faces. Our results support the hypothesis that impaired face processing in schizophrenia is related to early-stage deficits during the encoding and recognition of faces.

The Disrupted-in-Schizophrenia-1 Ser704Cys polymorphism and brain morphology in schizophrenia

The Disrupted-in-Schizophrenia-1 (DISC1) polymorphism is a strong candidate for a schizophrenia-susceptibility gene as it is widely expressed in cortical and limbic regions, but the effect of its genotype variation on brain morphology in schizophrenia is not well known. This study examined the association between the DISC1 Ser704Cys polymorphism and volumetric measurements for a broad range of fronto-parietal, temporal, and limbic-paralimbic regions using magnetic resonance imaging in a Japanese sample of 33 schizophrenia patients and 29 healthy comparison subjects. The Cys carriers had significantly larger volumes of the medial superior frontal gyrus and short insular cortex than the Ser homozygotes only for healthy comparison subjects. The Cys carriers tended to have a smaller supramarginal gyrus than the Ser homozygotes in schizophrenia patients, but not in healthy comparison subjects. The right medial superior frontal gyrus volume was significantly correlated with daily dosage of antipsychotic medication in Ser homozygote schizophrenia patients. These different genotype effects of the DISC1 Ser704Cys polymorphism on the brain morphology in schizophrenia patients and healthy comparison subjects suggest that variation in the DISC1 gene might be, at least partly, involved in the neurobiology of schizophrenia. Our findings also suggest that the DISC1 genotype variation might have some relevance to the medication effect on brain morphology in schizophrenia.

Reduced neuron density, enlarged minicolumn spacing and altered ageing effects in fusiform cortex in schizophrenia

Structural and functional MRI studies report reduced volume and activation of the fusiform gyrus in schizophrenia. The fusiform cortex is involved in object naming and face recognition. Neuron cell size, shape and density, glial cell density and minicolumn spacing in layers III and V of the fusiform cortex were assessed following systematic random sampling from 13 controls and 11 schizophrenic patients. Pyramidal cell density was reduced in schizophrenia. Non-pyramidal cell density was reduced in layer III of the left hemisphere in schizophrenia, mostly in females. Non-pyramidal cells were larger in schizophrenia. Glial cell density was unaltered. Fusiform minicolumn spacing was asymmetrically wider in the right hemisphere of normal control subjects. Minicolumns were less dense in schizophrenia, particularly in the left hemisphere of females and the right hemisphere of males. Reduced neuron density in the fusiform cortex in schizophrenia contributes to evidence of functional-anatomical abnormalities from neuroimaging and neuropathology studies. Anatomical sex differences in schizophrenia may relate to anatomical and cognitive sex differences associated with fusiform cortex in the normal population. Wider minicolumn spacing is consistent with reduced cell density and is linked to altered ageing in schizophrenia.

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.

Increased pituitary volume in schizophrenia spectrum disorders

While hypothalamic-pituitary-adrenal (HPA) axis hyperactivity has been implicated in psychotic disorders, previous magnetic resonance imaging (MRI) studies of the pituitary gland volume in schizophrenia have yielded controversial results. It is also unknown whether patients with schizophrenia spectrum such as schizotypal disorder exhibit pituitary volume changes. In this study, we investigated the pituitary volume using MRI in 47 schizotypal disorder patients (29 males, mean age=25.0 years), 72 schizophrenia patients (38 males, mean age=26.2 years), and 81 age and gender matched healthy controls (46 males, mean age=24.5 years). Both patient groups had a larger pituitary volume compared with controls, but no difference was found between the schizophrenia and schizotypal patients. The pituitary volume was larger in females than in males for all diagnostic groups. There was no association between the pituitary volume and type (typical versus atypical), daily dosage, or duration of antipsychotic medication in either patient group. These findings are consistent with a stress-diathesis model of schizophrenia and further suggest that the schizotypal patients share HPA axis hyperactivity with young established schizophrenia patients reflecting a common vulnerability to stress within the schizophrenia spectrum.

Global and temporal cortical folding in patients with early-onset schizophrenia

OBJECTIVE

Adult-onset schizophrenia has repeatedly been associated with disturbances in the temporal lobes and alterations in cortical folding, which are thought to reflect neurodevelopmental impairment. Early-onset schizophrenia (EOS; onset before 18 years) is considered to involve even more pronounced neurodevelopmental deviance across a wide range of brain structural measures. We hypothesized that overall alteration of cortical folding also applies to EOS, and EOS involves prominent structural aberrations in superior temporal and collateral sulci.

METHOD

Magnetic resonance T1 images of 51 patients with EOS and 59 healthy participants were investigated. A fully automated method was applied to the images to extract, label, and measure the sulcus area in the whole cortex. Cortical folding was assessed by computing global sulcal indices (the ratio between total sulcal area and total outer cortex area) for each hemisphere and local sulcal indices (the ratio between the area of labeled sulcus and total outer cortex area in the corresponding hemisphere) for superior temporal and collateral sulci.

RESULTS

Relative to healthy individuals, patients with EOS had significantly lower global sulcal indices in both hemispheres and a lower local sulcal index in the left collateral sulcus.

CONCLUSIONS

Reduced hemispheric sulcation appears to be a feature of schizophrenia, irrespective of age at onset. Structural aberration involving the left collateral sulcus may contribute to neurobiological substrate of EOS.

Cortical gray and white matter volume in unmedicated schizotypal and schizophrenia patients

Magnetic resonance imaging (MRI) studies have revealed fronto-temporal cortical gray matter volume reductions in schizophrenia. However, to date studies have not examined whether age- and sex-matched unmedicated schizotypal personality disorder (SPD) patients share some or all of the structural brain-imaging characteristics of schizophrenia patients. We examined cortical gray/white matter volumes in a large sample of unmedicated schizophrenia-spectrum patients (n=79 SPD, n=57 schizophrenia) and 148 healthy controls. MRI images were reoriented to standard position parallel to the anterior-posterior commissure line, segmented into gray and white matter tissue types, and assigned to Brodmann areas (BAs) using a postmortem-histological atlas. Group differences in regional volume of gray and white matter in the BAs were examined with MANOVA. Schizophrenia patients had significantly reduced gray matter volume widely across the cortex but more marked in frontal and temporal lobes. SPD patients had reductions in the same regions but only about half that observed in schizophrenia and sparing in key regions including BA10. In schizophrenia, greater fronto-temporal volume loss was associated with greater negative symptom severity and in SPD, greater interpersonal and cognitive impairment. Overall, our findings suggest that increased prefrontal volume in BA10 and sparing of volume loss in temporal cortex (BAs 22 and 20) may be a protective factor in SPD which reduces vulnerability to psychosis.

Stress sensitization in schizophrenia

It is well known that environmental factors, such as early life events, perinatal damage, and urbanicity, which interact with multiple genes, induces persistent sensitization to stress possibly through an imbalance in interactions between dopaminergic and glutamatergic systems. This stress sensitization may be critical in the development or relapse of schizophrenia. The neural correlates of a negative mood might be impaired, resulting in stress sensitization and difficulties in social adjustment (Dr. Habel). Urbanicity is associated with later schizophrenia. Metabolic stress induces stress sensitization via dysregulation of dopaminergic and/or noradrenergic systems in activated HVA and cortical response (Dr. Marcelis). The glutamatergic regulation activates HPA axis in stress response (Dr. Zelena). Ameloblast activity in human molar's enamel slowed by exposure to stress, and the segment of enamel rods is smaller, making a particular dark line. Stress sensitization may be induced at the age of 10.5 to 11.5 years resulting from severe emotional stress at the age of 10.5 to 11.5 years (Dr. Yui). It has been reported that volume reductions in the amygdala, hippocampus, superior temporal gyrus, and anterior parietal cortex common to both patient groups may represent the vulnerability to schizophrenia, while volume loss of the prefrontal cortex, posterior parietal cortex, cingulate, insula, and fusiform cortex preferentially observed in schizophrenia may be critical for overt manifestation of psychosis (Dr. Suzuki).

Parietal lobe volume deficits in schizophrenia spectrum disorders

There has been little attention given to whether parietal lobe structural deficits are present in patients with schizophrenia and related personality disorders. The current study was designed to examine parietal volume alterations between schizophrenia and schizotypal personality disorder. Twenty-five patients with schizotypal disorder, 53 patients with schizophrenia, and 59 healthy volunteers were scanned using high-resolution magnetic resonance imaging (MRI). Volume measurements of the postcentral gyrus (PoCG), precuneus, superior parietal gyrus (SuPG), supramarginal gyrus (SMG), and angular gyrus (AGG) were performed on consecutive 1-mm coronal slices. Gray matter volumes were reduced in all parietal subregions in patients with schizophrenia compared with healthy controls. White matter volumes were also reduced in the SuPG and PoCG. In contrast, the schizotypal subjects had gray matter reductions only in the PoCG, while other regions were not affected. In addition, there was a lack of normal significant-leftward asymmetry in the SMG in schizophrenia. These findings demonstrate that volume reductions in the somatosensory cortices are common morphological characteristics in schizophrenia spectrum disorders. The additional volume alterations in schizophrenia may support the notion that a deficit in the posterior parietal region is critical for the manifestation of overt psychotic symptoms.