Reduced anterior cingulate gyrus volume correlates with executive dysfunction in men with first-episode schizophrenia

Spectral perturbations of cortical dipoles during a dynamic visuo-spatial working memory task in schizophrenia

Altered neural oscillations during prestimulus-task conditions have been reported to be associated with aberrant information processing in schizophrenia. Spectral perturbations induced by visuo-spatial working memory (VSWM) task were investigated in patients and their first-degree relatives in order to study the biomarkers in schizophrenia. EEG was recorded using 128-channel during VSWM task in 28 patients, 27 first-degree relatives and 25 controls. After pre-processing and ICA, current dipole was estimated for each IC. Total of 1609 independent and localizable EEG components across all groups were used to compute ERSP during different events of task. Patients deactivated DMN, RSN, auditory cortex more compared to controls during search period to perform VSWM task. Relatives showed altered activation of right medial and inferior frontal gyri during different events and loads of task in lower frequencies compared to controls. Relatives also showed hyperactivity in right cingulate and parahippocampal gyri compared to controls. This is suggestive of genetic predisposition in schizophrenia and could act as vulnerability markers, further strengthened by no significant differences between patients and relatives. Altered processing of simultaneous ongoing events in patients and relatives can serve as state and trait-specific features of schizophrenia.

Structural connectivity associated with familial risk for mental illness: A meta‐analysis of diffusion tensor imaging studies in relatives of patients with severe mental disorders

Schizophrenia (SCZ), bipolar disorder (BD), and major depressive disorder (MDD) are heritable conditions with overlapping genetic liability. Transdiagnostic and disorder‐specific brain changes associated with familial risk for developing these disorders remain poorly understood. We carried out a meta‐analysis of diffusion tensor imaging (DTI) studies to investigate white matter microstructure abnormalities in relatives that might correspond to shared and discrete biomarkers of familial risk for psychotic or mood disorders. A systematic search of PubMed and Embase was performed to identify DTI studies in relatives of SCZ, BD, and MDD patients. Seed‐based d Mapping software was used to investigate global differences in fractional anisotropy (FA) between overall and disorder‐specific relatives and healthy controls (HC). Our search identified 25 studies that met full inclusion criteria. A total of 1,144 relatives and 1,238 HC were included in the meta‐analysis. The overall relatives exhibited decreased FA in the genu and splenium of corpus callosum (CC) compared with HC. This finding was found highly replicable in jack‐knife analysis and subgroup analyses. In disorder‐specific analysis, compared to HC, relatives of SCZ patients exhibited the same changes while those of BD showed reduced FA in the left inferior longitudinal fasciculus (ILF). The present study showed decreased FA in the genu and splenium of CC in relatives of SCZ, BD, and MDD patients, which might represent a shared familial vulnerability marker of severe mental illness. The white matter abnormalities in the left ILF might represent a specific familial risk for bipolar disorder.

A Systematic Review of Cognition-Brain Morphology Relationships on the Schizophrenia-Bipolar Disorder Spectrum

The nature of the relationship between cognition and brain morphology in schizophrenia-spectrum disorders (SSD) and bipolar disorder (BD) is uncertain. This review aimed to address this, by providing a comprehensive systematic investigation of links between several cognitive domains and brain volume, cortical thickness, and cortical surface area in SSD and BD patients across early and established illness stages. An initial search of PubMed and Scopus databases resulted in 1486 articles, of which 124 met inclusion criteria and were reviewed in detail. The majority of studies focused on SSD, while those of BD were scarce. Replicated evidence for specific regions associated with indices of cognition was minimal, however for several cognitive domains, the frontal and temporal regions were broadly implicated across both recent-onset and established SSD, and to a lesser extent BD. Collectively, the findings of this review emphasize the significance of both frontal and temporal regions for some domains of cognition in SSD, while highlighting the need for future BD-related studies on this topic.

Fronto-Parietal Gray Matter Volume Loss Is Associated with Decreased Working Memory Performance in Adolescents with a First Episode of Psychosis

Cognitive maturation during adolescence is modulated by brain maturation. However, it is unknown how these processes intertwine in early onset psychosis (EOP). Studies examining longitudinal brain changes and cognitive performance in psychosis lend support for an altered development of high-order cognitive functions, which parallels progressive gray matter (GM) loss over time, particularly in fronto-parietal brain regions. We aimed to assess this relationship in a subsample of 33 adolescents with first-episode EOP and 47 matched controls over 2 years. Backwards stepwise regression analyses were conducted to determine the association and predictive value of longitudinal brain changes over cognitive performance within each group. Fronto-parietal GM volume loss was positively associated with decreased working memory in adolescents with psychosis (frontal left (B = 0.096, p = 0.008); right (B = 0.089, p = 0.015); parietal left (B = 0.119, p = 0.007), right (B = 0.125, p = 0.015)) as a function of age. A particular decrease in frontal left GM volume best predicted a significant amount (22.28%) of the variance of decreased working memory performance over time, accounting for variance in age (14.9%). No such association was found in controls. Our results suggest that during adolescence, EOP individuals seem to follow an abnormal neurodevelopmental trajectory, in which fronto-parietal GM volume reduction is associated with the differential age-related working memory dysfunction in this group.

Neural correlates of cognitive deficits across developmental phases of schizophrenia

Schizophrenia is associated with cognitive deficits across all stages of the illness (i.e., high risk, first episode, early and chronic phases). Identifying the underlying neurobiological mechanisms of these deficits is an important area of scientific inquiry. Here, we selectively review evidence regarding the pattern of deficits across the developmental trajectory of schizophrenia using the five cognitive domains identified by the Research Domain Criteria (RDoC) initiative. We also report associated findings from neuroimaging studies. We suggest that most cognitive domains are affected across the developmental trajectory, with corresponding brain structural and/or functional differences. The idea of a common mechanism driving these deficits is discussed, along with implications for cognitive treatment in schizophrenia.

Neuroanatomical Correlates of the Unity and Diversity Model of Executive Function in Young Adults

Understanding the neuroanatomical correlates of individual differences in executive function (EF) is integral to a complete characterization of the neural systems supporting cognition. While studies have investigated EF-neuroanatomy relationships in adults, these studies often include samples with wide variation in age, which may mask relationships between neuroanatomy and EF specific to certain neurodevelopmental time points, and such studies often use unreliable single task measures of EF. Here we address both issues. First, we focused on a specific age at which the majority of neurodevelopmental changes are complete but at which age-related atrophy is not likely (N = 251; mean age of 28.71 years, SD = 0.57). Second, we assessed EF through multiple tasks, deriving three factors scores guided by the unity/diversity model of EF, which posits a common EF factor that influences all EF tasks, as well as an updating-specific and shifting-specific factor. We found that better common EF was associated with greater volume and surface area of regions in right middle frontal gyrus/frontal pole, right inferior temporal gyrus, as well as fractional anisotropy in portions of the right superior longitudinal fasciculus (rSLF) and the left anterior thalamic radiation. Better updating-specific ability was associated with greater cortical thickness of a cluster in left cuneus/precuneus, and reduced cortical thickness in regions of right superior frontal gyrus and right middle/superior temporal gyrus, but no aspects of white matter diffusion. In contrast, better shifting-specific ability was not associated with gray matter characteristics, but rather was associated with increased mean diffusivity and reduced radial diffusivity throughout much of the brain and reduced axial diffusivity in distinct clusters of the left superior longitudinal fasciculus, the corpus callosum, and the right optic radiation. These results demonstrate that associations between individual differences in EF ability and regional neuroanatomical properties occur not only within classic brain networks thought to support EF, but also in a variety of other regions and white matter tracts. These relationships appear to differ from observations made in emerging adults (Smolker et al., 2015), which might indicate that the brain systems associated with EF continue to experience behaviorally relevant maturational process beyond the early 20s.

Motor system dysfunction in the schizophrenia diathesis: Neural systems to neurotransmitters

Motor control is a ubiquitous aspect of human function, and from its earliest origins, abnormal motor control has been proposed as being central to schizophrenia. The neurobiological architecture of the motor system is well understood in primates and involves cortical and sub-cortical components including the primary motor cortex, supplementary motor area, dorsal anterior cingulate cortex, the prefrontal cortex, the basal ganglia, and cerebellum. Notably all of these regions are associated in some manner to the pathophysiology of schizophrenia. At the molecular scale, both dopamine and γ-Aminobutyric Acid (GABA) abnormalities have been associated with working memory dysfunction, but particularly relating to the basal ganglia and the prefrontal cortex respectively. As evidence from multiple scales (behavioral, regional and molecular) converges, here we provide a synthesis of the bio-behavioral relevance of motor dysfunction in schizophrenia, and its consistency across scales. We believe that the selective compendium we provide can supplement calls arguing for renewed interest in studying the motor system in schizophrenia. We believe that in addition to being a highly relevant target for the study of schizophrenia related pathways in the brain, such focus provides tractable behavioral probes for in vivo imaging studies in the illness. Our assessment is that the motor system is a highly valuable research domain for the study of schizophrenia.

Abnormal interactions of verbal- and spatial-memory networks in young people at familial high-risk for schizophrenia

BACKGROUND

Working memory impairment (especially in verbal and spatial domains) is the core neurocognitive impairment in schizophrenia and the familial high-risk (FHR) population. Inconsistent results have been reported in clinical and neuroimaging studies examining the verbal- and spatial-memory deficits in the FHR subjects, due to sample differences and lack of understanding on interactions of the brain regions for processing verbal- and spatial-working memory.

METHODS

Functional MRI data acquired during a verbal- vs. spatial-memory task were included from 51 young adults [26 FHR and 25 controls]. Group comparisons were conducted in brain activation patterns responding to 1) verbal-memory condition (A), 2) spatial-memory condition (B), 3) verbal higher than spatial (A-B), 4) spatial higher than verbal (B-A), 5) conjunction of brain regions that were activated during both A and B (A∧B). Group difference of the laterality index (LI) in inferior frontal lobe for condition A was also assessed.

RESULTS

Compared to controls, the FHR group exhibited significantly decreased brain activity in left inferior frontal during A, and significantly stronger involvement of ACC, PCC, paracentral gyrus for the contrast of A-B. The LI showed a trend of reduced left-higher-than-right pattern for verbal-memory processing in the HR group.

CONCLUSIONS

Our findings suggest that in the entire functional brain network for working-memory processing, verbal information processing associated brain pathways are significantly altered in people at familial high risk for developing schizophrenia. Future studies will need to examine whether these alterations may indicate vulnerability for predicting the onset of Schizophrenia.

Abnormalities of cingulate cortex in antipsychotic-naïve chronic schizophrenia

While several morphometric studies have postulated a critical contribution of the cingulate cortex (CC) to the pathophysiology of schizophrenia based on abnormalities in CC volume, other studies have been inconclusive. Most such studies have focused only on changes in cortical volume, whereas other morphometric parameters such as surface area and cortical thickness could be more relevant and possibly account for these discrepancies. Furthermore, factors such as antipsychotic drug use and treatment duration may also influence cortical morphology. To clarify the association between schizophrenia and CC deficits, we investigated morphometric abnormalities of the CC in antipsychotic drug (AD)-naïve chronic schizophrenia patients by comparing T1-weighted magnetic resonance images (T1WI-MRI) from patients (n=17) to healthy controls (n=17) using the surface-based morphometry program FreeSurfer. Partial correlations were examined between abnormal morphometric measures and both clinical variables and cognitive performance scores. Compared to healthy controls, drug-naïve schizophrenia patients exhibited significantly lower volumes in both left rostral anterior CC (rACC) and left posterior CC (PCC). These reductions in CC volume resulted from reduced surface area rather than reduced cortical thickness. There was also a significant relationship between left PCC volume and working memory in patients. No significant correlations were observed between CC volume and clinical variables. The results suggest that abnormalities in the CC as manifested by reduced surface area may contribute to cognitive dysfunction in schizophrenia. This article is part of a Special Issue entitled SI: PSC and the brain.

Contribution of sex hormones to gender differences in schizophrenia: A review

Female patients with schizophrenia tend to have a more benign course and better outcomes than males. One proposed explanation is the differential influence of male and female sex hormones, including estrogen, progesterone, testosterone, and dehydroepiandrosterone (DHEA) and its sulfate (DHEAS). Such benefit may be mediated by their effects on neurotransmitters and neuroprotection. Besides altered estrogen and DHEA/DHEAS levels in female patients, data is equivocal on hormonal differences between patients and controls. However, several reports note a mostly negative correlation between estrogen levels and symptom severity in both genders, and a positive correlation between estrogen levels and neurocognition but mainly in females. Adjunctive estrogen appears to improve symptoms in both genders. Progesterone levels have inconsistent links to symptom severity in both genders, and correlate positively with neurocognition but only in males. Estrogen-progesterone combination shows preliminary benefits as augmentation for both symptoms and neurocognition in females. Testosterone levels correlate inversely with negative symptoms in males and have inconsistent associations with neurocognition in both genders. Testosterone augmentation reduced negative symptoms in male patients in a pilot investigation, but has not been evaluated for neurocognition in either gender. DHEA/DHEAS have mixed results for their association with, and clinical utility for, symptoms and neurocognition in both genders. Overall, data on the impact of sex hormones on clinical course or as treatment for schizophrenia is limited, but estrogen has most evidence for positive influence and clinical benefit. The possibly greater tolerability and broader impact of these hormones versus existing medications support further exploration of their use.

Cortical substrates and functional correlates of auditory deviance processing deficits in schizophrenia

Although sensory processing abnormalities contribute to widespread cognitive and psychosocial impairments in schizophrenia (SZ) patients, scalp-channel measures of averaged event-related potentials (ERPs) mix contributions from distinct cortical source-area generators, diluting the functional relevance of channel-based ERP measures. SZ patients (n = 42) and non-psychiatric comparison subjects (n = 47) participated in a passive auditory duration oddball paradigm, eliciting a triphasic (Deviant−Standard) tone ERP difference complex, here termed the auditory deviance response (ADR), comprised of a mid-frontal mismatch negativity (MMN), P3a positivity, and re-orienting negativity (RON) peak sequence. To identify its cortical sources and to assess possible relationships between their response contributions and clinical SZ measures, we applied independent component analysis to the continuous 68-channel EEG data and clustered the resulting independent components (ICs) across subjects on spectral, ERP, and topographic similarities. Six IC clusters centered in right superior temporal, right inferior frontal, ventral mid-cingulate, anterior cingulate, medial orbitofrontal, and dorsal mid-cingulate cortex each made triphasic response contributions. Although correlations between measures of SZ clinical, cognitive, and psychosocial functioning and standard (Fz) scalp-channel ADR peak measures were weak or absent, for at least four IC clusters one or more significant correlations emerged. In particular, differences in MMN peak amplitude in the right superior temporal IC cluster accounted for 48% of the variance in SZ-subject performance on tasks necessary for real-world functioning and medial orbitofrontal cluster P3a amplitude accounted for 40%/54% of SZ-subject variance in positive/negative symptoms. Thus, source-resolved auditory deviance response measures including MMN may be highly sensitive to SZ clinical, cognitive, and functional characteristics.

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Six source clusters contributing to the triphasic auditory deviance response were identified.

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Source resolved responses are sensitive to SZ clinical, cognitive, and function characteristics.

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Source resolved responses accounted for up to half the variance in cognitive and symptom scales.

Diffusion tensor imaging study of white matter damage in chronic meningitis

Tuberculous meningitis (TBM) and cryptococcal meningitis (CM) are two of the most common types of chronic meningitis. This study aimed to assess whether chronic neuro-psychological sequelae are associated with micro-structure white matter (WM) damage in HIV-negative chronic meningitis. Nineteen HIV-negative TBM patients, 13 HIV-negative CM patients, and 32 sex- and age-matched healthy volunteers were evaluated and compared. The clinical relevance of WM integrity was studied using voxel-based diffusion tensor imaging (DTI) magnetic resonance imaging. All of the participants underwent complete medical and neurologic examinations, and neuro-psychological testing. Differences in DTI indices correlated with the presence of neuro-psychological rating scores and cerebrospinal fluid (CSF) analysis during the initial hospitalization. Patients with CM had more severe cognitive deficits than healthy subjects, especially in TBM. There were changes in WM integrity in several limbic regions, including the para-hippocampal gyrus and cingulate gyrus, and in the WM close to the globus pallidus. A decline in WM integrity close to the globus pallidus and anterior cingulate gyrus was associated with worse CSF analysis profiles. Poorer DTI parameters directly correlated with worse cognitive performance on follow-up. These correlations suggest that WM alterations may be involved in the psychopathology and pathophysiology of co-morbidities. Abnormalities in the limbic system and globus pallidus, with their close relationship to the CSF space, may be specific biomarkers for disease evaluation.

Tai Chi Chuan optimizes the functional organization of the intrinsic human brain architecture in older adults

Whether Tai Chi Chuan (TCC) can influence the intrinsic functional architecture of the human brain remains unclear. To examine TCC-associated changes in functional connectomes, resting-state functional magnetic resonance images were acquired from 40 older individuals including 22 experienced TCC practitioners (experts) and 18 demographically matched TCC-naïve healthy controls, and their local functional homogeneities across the cortical mantle were compared. Compared to the controls, the TCC experts had significantly greater and more experience-dependent functional homogeneity in the right post-central gyrus (PosCG) and less functional homogeneity in the left anterior cingulate cortex (ACC) and the right dorsal lateral prefrontal cortex. Increased functional homogeneity in the PosCG was correlated with TCC experience. Intriguingly, decreases in functional homogeneity (improved functional specialization) in the left ACC and increases in functional homogeneity (improved functional integration) in the right PosCG both predicted performance gains on attention network behavior tests. These findings provide evidence for the functional plasticity of the brain’s intrinsic architecture toward optimizing locally functional organization, with great implications for understanding the effects of TCC on cognition, behavior and health in aging population.

Reduced anterior cingulate gray matter volume and thickness in subjects with deficit schizophrenia

BACKGROUND

Patients with deficit schizophrenia (D-SZ) differ from patients with the non-deficit form of schizophrenia (ND-SZ) in several aspects such as risk factors, neurobiological correlates, treatment response and clinical outcome. It has been debated if brain morphology could differentiate D-SZ from ND-SZ. Anterior cingulate gyrus (ACG) region regulates cognitive and emotional processing and past studies reported structural changes in this region in patients with SZ.

METHODS

1.5-T 3D MRI scans were obtained from 18 D-SZ patients, 30 ND-SZ patients and 82 healthy controls (HCs). We used FreeSurfer-initalized labeled cortical distance mapping (FSLCDM) to measure ACG gray matter volume, cortical thickness, and area of the gray/white interface. Furthermore, cortical thickness was compared among the 3 groups using the pooled labeled cortical distance mapping (LCDM) method.

RESULTS

The ACG cortex of the D-SZ group was thinner than the ND-SZ group. Pooled LCDM demonstrated that the ACG cortex was bilaterally thinner in both the ND-SZ group and the D-SZ group compared with the control group. The right ACG gray matter volume was significantly reduced in D-SZ patients as compared with healthy controls (p=0.005 CONCLUSION: Our data suggest that qualitative, categorical differences in neuroanatomy may distinguish between deficit and non-deficit subtypes of schizophrenia.

Altered asymmetry of the anterior cingulate cortex in subjects at genetic high risk for psychosis

OBJECTIVE

Many studies have reported that patients with schizophrenia often have structural abnormalities of the anterior cingulate cortex (ACC) and that some of these seem to be of genetic origin, therefore predating the onset of illness. The present study aimed to investigate whether these alterations in the ACC are genetic in origin by comparing the morphological patterns of three groups: normal controls, subjects at genetic high risk (GHR) for psychosis, and patients with schizophrenia. The relationships between morphological variations and executive function were also investigated.

METHODS

This study examined the magnetic resonance images of cingulate sulcus/paracingulate sulcus (CS/PCS) folding patterns in 222 subjects (103 normal subjects, 30 individuals at GHR, and 89 patients with schizophrenia) and evaluated differences in the morphological and asymmetrical patterns of the ACC among groups. Neurocognitive tests were then performed and differences in cognitive performance were analyzed according to morphological variation.

RESULTS

Differences in PCS folding were detected; the control group was significantly more likely than were other groups to show a well-developed left PCS (p=0.009) and leftward asymmetry of the PCS (p<0.001). However, neither GHR subjects (p=0.346) nor patients (p=0.784) showed this leftward asymmetry. No statistically significant differences in CS continuity were observed. A more prominent left PCS (p=0.031) and leftward PCS asymmetry (p=0.030) were both associated with higher scores on the working memory task.

CONCLUSION

The results suggest that GHR subjects have distinct neurodevelopmental anomalies that resemble those of patients with schizophrenia even though they do not display any psychotic symptoms. Certain developmental alterations in the ACC, such as the loss of leftward sulcal asymmetry in patients with schizophrenia, might be related to genetic factors. Additionally, this morphological alteration might partly account for the impaired executive function in schizophrenia.

Quetiapine and flupentixol differentially improve anterior cingulate cortex function in schizophrenia patients: an event-related potential study

Atypical antipsychotic agents are a frequently and effectively used treatment in schizophrenia and psychotic disorders. Other than conventional antipsychotics, which mainly exert their pharmacological effect in subcortical dopaminergic systems, atypical antipsychotics additionally affect partly serotonergically innervated structures within prefrontal areas, such as the anterior cingulate cortex (ACC). However, only few controlled, randomized studies have so far investigated direct and indirect effects of atypical antipsychotics on the ACC and, up until now, no clinical investigation has exclusively addressed the specific effects of quetiapine on ACC function. The present study assessed ACC function in 18 quetiapine-medicated patients and 13 flupentixol-treated patients suffering from schizophrenia by means of the error-related negativity (ERN), a neurophysiological marker of ACC function, in a pre-post design. Between-group comparisons revealed different effects of quetiapine and flupentixol on ACC function despite similar improvement in psychopathology, cognitive performance and quality of life. Whereas atypical treatment was associated with an increase in amplitudes over time, there were prolonged ERN peak latencies in patients treated with the typical agent. Moreover, treatment effects depended on baseline prefrontal cortex function in both groups. We conclude that both flupentixol and quetiapine improve prefrontal function especially in patients with weak initial ACC function which might be due to their shared affinity for serotonin receptors in frontal brain regions. However, since this affinity is more pronounced for quetiapine, patients treated with quetiapine seemed to profit more evidently concerning their prefrontal cortex function compared to patients of the flupentixol group, who exhibited a compensatory prolongation of processes.

Deficits in trace fear memory in a mouse model of the schizophrenia risk gene TCF4

The basic helix-loop-helix (bHLH) transcription factor TCF4 was confirmed in the combined analysis of several large genome-wide association studies (GWAS) as one of the rare highly replicated significant schizophrenia (SZ) susceptibility genes in large case-control cohorts. Focused genetic association studies showed that TCF4 influences verbal learning and memory, and modulates sensorimotor gating. Mice overexpressing Tcf4 in the forebrain (Tcf4tg) display cognitive deficits in hippocampus-dependent learning tasks and impairment of prepulse inhibition, a well-established endophenotype of SZ. The spectrum of cognitive deficits in SZ subjects, however, is broad and covers attention, working memory, and anticipation. Collectively, these higher order cognitive processes and the recall of remote memories are thought to depend mainly on prefrontal cortical networks. To further investigate cognitive disturbances in Tcf4tg mice, we employed the trace fear conditioning paradigm that requires attention and critically depends on the anterior cingulate cortex (ACC). We show that Tcf4tg mice display deficits in recent and remote trace fear memory and are impaired at anticipating aversive stimuli. We also assessed mRNA expression of the neuronal activity-regulated gene Fos in the ACC and hippocampus. Upon trace conditioning, Fos expression is reduced in Tcf4tg mice as compared to controls, which parallels cognitive impairments in this learning paradigm. Collectively, these data indicate that the reduced cognitive performance in Tcf4tg mice includes deficits at the level of attention and behavioral anticipation.

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.

Effects of age on prefrontal subregions and hippocampal volumes in young and middle-aged healthy humans

There are limited data available regarding the effects of age and sex on discrete prefrontal gray and white matter volumes or posterior and anterior hippocampal volumes in healthy humans. Volumes of the superior frontal gyrus, anterior cingulate gyrus, and orbital frontal lobe were computed manually from contiguous magnetic resonance (MR) images in 83 (39M/44F) healthy humans (age range = 16-40) and segmented into gray and white matter. Volumes of the posterior and anterior hippocampal formation were also computed with reliable separation of the anterior hippocampal formation from the amygdala. There were significant age-by-tissue type interactions for the superior frontal gyrus and orbital frontal lobe such that gray matter within these regions correlated significantly and inversely with age. In contrast, no significant age effects were evident within regional white matter volumes. Analysis of hippocampal volumes indicated that men had larger volumes of the anterior, but not posterior hippocampal formation compared to women even following correction for total brain size. These data highlight age effects within discrete prefrontal cortical gray matter regions in young and middle aged healthy humans and suggest that the white matter comprising these regions may be more resistant to age effects. Furthermore, understanding the potential role of sex and age in mediating prefrontal cortical and hippocampal volumes may have strong relevance for psychiatric disorders such as schizophrenia that have implicated neurodevelopmental abnormalities within frontotemporal circuits in their pathogenesis.

Effects of DTNBP1 genotype on brain development in children

BACKGROUND

Schizophrenia is a neurodevelopmental disorder, and risk genes are thought to act through disruption of brain development. Several genetic studies have identified dystrobrevin-binding protein 1 (DTNBP1, also known as dysbindin) as a potential susceptibility gene for schizophrenia, but its impact on brain development is poorly understood. The present investigation examined for the first time the effects of DTNBP1 on brain structure in children. Our hypothesis was that a genetic variation in DTNBP1 (i.e., the single nucleotide polymorphism rs2619538) would be associated with differences in both gray and white matter brain regions previously implicated in schizophrenia.

METHODS

Magnetic resonance imaging and voxel-based morphometry were used to examine brain structure in 52 male children aged between 10 and 12 years. Statistical inferences on the effects of DTNBP1 genotype on gray and white matter volume (GMV and WMV) were made at p < .05 after family-wise error correction for multiple comparisons across the whole brain.

RESULTS

Individuals homozygous for the schizophrenia high-risk allele (AA) compared with those homozygous for the low-risk allele (TT) expressed reduced GMV in the left anterior cingulate gyrus and reduced WMV in the left medial frontal area.

CONCLUSIONS

Our results suggest that genetic variation in DTNBP1 is associated with differences in gray and white matter; and that these effects are already evident in children as young as 10-12 years. These findings are consistent with the notion that the DTNBP1 genotype influences brain development and may thereby modulate vulnerability to schizophrenia.

The ZNF804A gene: characterization of a novel neural risk mechanism for the major psychoses

Schizophrenia and bipolar disorder share genetic risk, brain vulnerability, and clinical symptoms. The ZNF804A risk variant, rs1344706, confers susceptibility for both disorders. This study aimed to identify neural mechanisms common to both schizophrenia and bipolar disorder through this variant's potential effects on cortical thickness, white matter tract integrity, and cognitive function. Imaging, genetics, and cognitive measures were ascertained in 62 healthy adults aged between 18 and 59 years. High-resolution multimodal MRI/DTI imaging was used to measure cortical thickness and major frontotemporal and interhemispheric white matter tracts. The general linear model was used to examine the influence of the ZNF804A rs1344706 risk variant on cortical thickness, white matter tract integrity, and cognitive measures. Individuals homozygous for the risk variant ('A' allele) demonstrated reduced cortical gray matter thickness in the superior temporal gyrus, and in the anterior and posterior cingulate cortices compared with C-allele carriers. No effect of the risk variant on microstructural integrity of white matter tracts was found. Reduced attention control was found in risk allele homozygotes, aligning with findings in the anterior cingulate cortex. Our data provide a novel, genetically based neural risk mechanism for the major psychoses by effects of the ZNF804A risk variant on neural structures and cognitive function susceptible in both disorders. Our findings link genetic, imaging, and cognitive susceptibility relevant to both schizophrenia and bipolar disorder.

Gray matter volume deficits are associated with motor and attentional impairments in adolescents with schizophrenia

Cognitive deficits have been well described in adolescents with schizophrenia, but little is known about the neuroanatomical basis of these abnormalities. The authors examined whether neuropsychological deficits observed in adolescents with schizophrenia were associated with cortical gray matter volume deficits. Volumes of the superior frontal gyrus, anterior cingulate gyrus and orbital frontal lobe were outlined manually from contiguous MR images and automatically segmented into gray and white matter in 52 patients and 48 healthy volunteers. Subjects received a comprehensive neuropsychological test battery, assessing five different functional domains: executive, attention, verbal memory, motor and sensory motor. Children and adolescents with schizophrenia were found to have lower total cortical and lower superior frontal gyrus gray matter volumes and lower test scores across all functional domains compared to healthy volunteers. Among patients, the lower total cortical gray matter volume was associated with worse functioning on the attention and motor domains. Our findings point to widespread, perhaps multifocal, pathology as contributing to cognitive dysfunction in adolescents with schizophrenia.

Orbitofrontal cortex abnormalities in schizophrenia

The magnetic resonance imaging studies investigating the volumes of the orbitofrontal cortex in patients suffering from schizophrenia are here presented, trying to elucidate its role for the pathophysiology and for the cognition of the disease.

Brain anatomical abnormalities in high-risk individuals, first-episode, and chronic schizophrenia: an activation likelihood estimation meta-analysis of illness progression

OBJECTIVE

The present study reviewed voxel-based morphometry (VBM) studies on high-risk individuals with schizophrenia, patients experiencing their first-episode schizophrenia (FES), and those with chronic schizophrenia. We predicted that gray matter abnormalities would show progressive changes, with most extensive abnormalities in the chronic group relative to FES and least in the high-risk group.

METHOD

Forty-one VBM studies were reviewed. Eight high-risk studies, 14 FES studies, and 19 chronic studies were analyzed using anatomical likelihood estimation meta-analysis.

RESULTS

Less gray matter in the high-risk group relative to controls was observed in anterior cingulate regions, left amygdala, and right insula. Lower gray matter volumes in FES compared with controls were also found in the anterior cingulate and right insula but not the amygdala. Lower gray matter volumes in the chronic group were most extensive, incorporating similar regions to those found in FES and high-risk groups but extending to superior temporal gyri, thalamus, posterior cingulate, and parahippocampal gryus. Subtraction analysis revealed less frontotemporal, striatal, and cerebellar gray matter in FES than the high-risk group; the high-risk group had less gray matter in left subcallosal gyrus, left amygdala, and left inferior frontal gyrus compared with FES. Subtraction analysis confirmed lower gray matter volumes through ventral-dorsal anterior cingulate, right insula, left amygdala and thalamus in chronic schizophrenia relative to FES.

CONCLUSIONS

Frontotemporal brain structural abnormalities are evident in nonpsychotic individuals at high risk of developing schizophrenia. The present meta-analysis indicates that these gray matter abnormalities become more extensive through first-episode and chronic illness. Thus, schizophrenia appears to be a progressive cortico-striato-thalamic loop disorder.

Cannabis use and progressive cortical thickness loss in areas rich in CB1 receptors during the first five years of schizophrenia

Cerebral grey matter volume reductions are progressive in schizophrenia, with larger grey matter volume decreases associated with cannabis use. It is unknown whether this grey matter loss is globally distributed over the entire brain or more pronounced in specific cortical brain regions. Fifty-one patients with recent-onset schizophrenia and 31 matched healthy subjects were included. For all subjects, magnetic resonance imaging scans were obtained at inclusion and at 5-year follow-up. Nineteen patients (ab-)used cannabis but no other illicit drugs; 32 patients and the healthy comparison subjects did not use any drugs during the 5-year follow-up. At follow-up, clinical outcome was measured. To evaluate the local differences in cortical thickness change over five years between the two groups regression analysis was carried out over the cortical surface. At inclusion cortical thickness did not differ between patients and controls and between cannabis-using and non-using patients. Over the follow-up period we found excessive thinning of the right supplementary motor cortex, inferior frontal cortex, superior temporal gyrus, angular gyrus, occipital and parietal lobe in patients relative to controls after controlling for cannabis use. Patients who used cannabis showed additional thinning in the left dorsolateral prefrontal cortex (DLPFC), left anterior cingulate cortex (ACC) and left occipital lobe as compared to those patients that did not use cannabis during the scan interval. First-episode schizophrenia patients who use cannabis show a more pronounced cortical thinning than non-using patients in areas known for their high density of CB1 receptors, such as the ACC and the DLPFC.

Anterior cingulum volumetry, auditory P300 in schizophrenia with negative symptoms

The anterior cingulate cortex (ACC) is located at the rostum of the corpus callosum and involved in both cognitive and emotional brain processes. It has been suggested to be involved in P300 event-related potential generation. A large sample of schizophrenia inpatients and controls was examined in order to assess the potential relationship between ACC volumes and P300 characteristics in patients with more pronounced negative symptoms. In 50 male schizophrenia patients and 50 matched controls, auditory P300 and structural magnetic resonance imaging volume measurements of the ACC were obtained. Patients' negative symptoms were assessed using the PANSS (Positive and Negative Syndrome Scale). Volumetry of ACC subregions revealed a volume reduction in patients with schizophrenia compared with controls in right hemispheric rostral ACC subregions that were most pronounced in more negative schizophrenia patients. There was a positive correlation between PZ P300 amplitude and total ACC volume in the right hemisphere in schizophrenia patients with less negative symptoms. The results support the assumption that structural changes of the ACC are more pronounced in subgroups of schizophrenia patients with more negative psychopathology. In addition, while right hemisphere ACC volumes significantly differ between schizophrenia subgroups, combining measures of event-related potential (ERP) and ACC volumetry does not add additional information.

Anterior cingulate and paracingulate sulci morphology in patients with schizophrenia

The anterior cingulate cortex is a cerebral region engaged in several emotional and cognitive functions. The aim of this study was to investigate possible anterior cingulate and paracingulate sulcal abnormalities in schizophrenia. Twenty-three patients with DSM-IV diagnoses of schizophrenia were compared with 23 healthy subjects matched for age, gender, and parental socioeconomic status. Magnetic resonance images were used to explore the morphology of these regions, with volume and maximum depth being measured by an automated method of sulcal recognition. Additionally, voxel-based morphometry (VBM) was performed to analyze possible reduction in gray and white matter of the anterior cingulate region. A smaller volume of the left anterior cingulate sulcus (ACS) was observed in patients with schizophrenia when compared with healthy controls. Furthermore, female patients showed a reduction in volume of the left ACS and an increase of the right paracingulate sulcus (PCS) compared to female controls. There was also a significant relationship between the depth of right PCS and neuroleptic exposure. VBM analysis showed a reduction in left anterior cingulate gray matter. These findings provide further evidence of left anterior middle frontal cortex abnormalities in schizophrenia. In addition, the results suggest gender differences in the structural abnormalities of the illness.

Investigating relationships between cortical thickness and cognitive performance in patients with schizophrenia and healthy adults

Relationships between prefrontal and temporal lobe grey matter volumes as assessed by magnetic resonance imaging and neurocognitive test results have been reported in schizophrenia. This investigation aimed to localize brain regions where cortical thickness and neurocognitive performance were related, and investigate if such relationships might differ in schizophrenia patients and healthy controls. Sixty-seven patients with schizophrenia and 69 healthy controls were characterized by neurocognitive testing and by brain cortical thickness maps. Putative cortical thickness/cognitive score relationships were investigated with contrast analyses of general linear models for the combined sample. Regions in which relationships were present were further investigated for diagnostic interaction. In the combined sample, significant positive relationships were found between frontal, temporal and occipital regions and tests for verbal IQ, verbal learning and executive functions. Diagnostic interaction was found for the relationships between verbal IQ and the right temporo-occipital junction and the left middle occipital gyrus. In conclusion, the significant relationships between cortical thickness and neurocognitive performances were localized in brain areas known to be involved in cognition. The relationships were similar in patients and controls, except for the right temporo-occipital and left occipital cortical areas, indicating a disrupted structure-function relationship in patients with schizophrenia compared to healthy control subjects.

Voxel-based morphometry comparison between first episodes of psychosis with and without evolution to schizophrenia

First episodes (FE) of psychosis may evolve or not to schizophrenia in ensuing years, but there is a lack of reliable predictors of which patients will have to face such an unfavorable outcome. Given the replicated structural alterations of the brain in schizophrenia, it seems advisable to assess whether the alterations of this kind that can be detected at the time of an initial psychotic episode are different depending on the outcome of the patients. To this end, here we applied voxel-based morphometry to assess whether the degree of cerebral abnormalities differ between 30 FE patients who evolved to schizophrenia in the ensuing 2years and another 14 FE patients who could not be diagnosed as such during that period. Forty-one controls were also included in the study. We found that the FE patients who evolved to schizophrenia had a significantly lower GM value than the controls bilaterally in the left dorsolateral prefrontal (BA 9) and in left anterior cingulate (BA 33) regions while the FE patients who did not develop schizophrenia showed a distinct, right-sided pattern of deviation (visual cortex, superior temporal gyrus and inferior frontal). The direct comparison between FE patients who evolved or not evolved to schizophrenia did not reveal significant differences. Taken together, our results support the notion that brain abnormalities may be different in psychotic FE patients depending on their evolution in the medium term.

Source-based morphometry of gray matter volume in men with first-episode schizophrenia

OBJECTIVES

There is a lot of variability between the results of studies reporting the pattern of gray matter volume changes in schizophrenia. Methodological issues may play an important role in this heterogeneity. The aim of the present study was to replicate the better performance of multivariate "source-based morphometry" (SBM) over the mass-univariate approach.

EXPERIMENTAL DESIGN

Voxel-based morphometry of Jacobian-modulated gray matter volume images, using voxel and cluster level inference, and SBM were performed in a group of first-episode schizophrenia patients (N = 49) and healthy controls (N = 127).

RESULTS

Using SBM we were able to find a significant reduction of gray matter volume in fronto-temporo-cerebellar areas whereas no significant results were obtained using voxel-based morphometry.

CONCLUSION

Multivariate analysis of gray matter volume seems to be a suitable method for characterization of the pattern of changes at the beginning of the illness in schizophrenia subjects.

Executive function, neural circuitry, and genetic mechanisms in schizophrenia

After decades of research aimed at elucidating the pathophysiology and etiology of schizophrenia, it has become increasingly apparent that it is an illness knowing few boundaries. Psychopathological manifestations extend across several domains, impacting multiple facets of real-world functioning for the affected individual. Even within one such domain, arguably the most enduring, difficult to treat, and devastating to long-term functioning-executive impairment-there are not only a host of disrupted component processes, but also a complex underlying dysfunctional neural architecture. Further, just as implicated brain structures (eg, dorsolateral prefrontal cortex) through postmortem and neuroimaging techniques continue to show alterations in multiple, interacting signaling pathways, so too does evolving understanding of genetic risk factors suggest multiple molecular entry points to illness liability. With this expansive network of interactions in mind, the present chapter takes a systems-level approach to executive dysfunction in schizophrenia, by identifying key regions both within and outside of the frontal lobes that show changes in schizophrenia and are important in cognitive control neural circuitry, summarizing current knowledge of their relevant functional interactions, and reviewing emerging links between schizophrenia risk genetics and characteristic executive circuit aberrancies observed with neuroimaging methods.

Schizophrenia patients and their healthy siblings share disruption of white matter integrity in the left prefrontal cortex and the hippocampus but not the anterior cingulate cortex

Healthy siblings of schizophrenia patients have an almost 9-fold higher risk for developing the illness than the general population. Disruption of white matter (WM) integrity as indicated by reduced fractional anisotropy (FA) derived from diffusion tensor imaging (DTI), is believed to be the key substrate of schizophrenia. However, it remains unclear whether schizophrenia patients and their healthy siblings share a specific pattern of disruption of WM integrity that may be related to the disease risk. The objective of this study is to determine whether a specific brain regional pattern of disruption of WM integrity is shared by schizophrenia patients and their healthy siblings. We investigated brain white matter abnormalities by voxel-based analysis of white matter FA data acquired from diffusion tensor imaging in 34 pairs of schizophrenia patients and their healthy siblings, as well as in 32 healthy controls. Both schizophrenia patients and their healthy siblings showed reduced white matter FA in the left prefrontal cortex and the hippocampus in comparison to healthy controls, without significant difference between patients and siblings. In marked contrast, only schizophrenia patients exhibited reduced white matter FA in the left anterior cingulate cortex in comparison to both siblings and controls, without significant difference between siblings and controls. Thus, schizophrenia patients and their healthy siblings share disruption of WM integrity in the left prefrontal cortex and the hippocampus that may be related to higher risk of healthy siblings to develop schizophrenia, which may be eventually attributed to additional disruption of WM integrity in the left anterior cingulate cortex.

Anatomical abnormalities of the anterior cingulate cortex in schizophrenia: bridging the gap between neuroimaging and neuropathology

The anterior cingulate cortex (ACC) is a functionally heterogeneous region involved in diverse cognitive and emotional processes that support goal-directed behaviour. Structural magnetic resonance imaging (MRI) and neuropathological findings over the past two decades have converged to suggest abnormalities in the region may represent a neurobiological basis for many of the clinical manifestations of schizophrenia. However, while each approach offers complimentary information that can provide clues regarding underlying patholophysiological processes, the findings from these 2 fields are seldom integrated. In this article, we review structural neuroimaging and neuropathological studies of the ACC, focusing on the unique information they provide. The available imaging data suggest grey matter reductions in the ACC precede psychosis onset in some categories of high-risk individuals, show sub-regional specificity, and may progress with illness duration. The available post-mortem findings indicate these imaging-related changes are accompanied by reductions in neuronal, synaptic, and dendritic density, as well as increased afferent input, suggesting the grey matter differences observed with MRI arise from alterations in both neuronal and non-neuronal tissue compartments. We discuss the potential mechanisms that might facilitate integration of these findings and consider strategies for future research.

Altered reward functions in patients on atypical antipsychotic medication in line with the revised dopamine hypothesis of schizophrenia

OBJECTIVE

To study the mesolimbic dopamine system during expectation and receipt or omission of rewards in partially remitted patients with schizophrenia treated with the atypical antipsychotic olanzapine.

METHODS

We studied 16 patients with a current episode of schizophrenia, all treated with the atypical drug olanzapine, and 16 healthy subjects using functional magnetic resonance imaging. Subjects performed a delayed incentive paradigm with monetary rewards.

RESULTS

During reward expectation, both, patients with schizophrenia and healthy control subjects, showed activation of the ventral striatum and midbrain in the vicinity of the ventral tegmental area. Significant categorical group differences emerged in the anterior cingulate cortex with only healthy controls showing increasing activation with increasing reward. In the patients, activation of this region was inversely correlated with positive symptoms. During outcome, both, patients with schizophrenia and healthy controls, showed activation of the ventral striatum and the mesial prefrontal cortex. Significant categorical group differences emerged in the right ventrolateral prefrontal cortex for the salience contrast with healthy controls showing a U-shaped activation curve, i.e., higher activation for either omission or receipt of reward compared to no reward.

CONCLUSIONS

Our findings partially support the current concept of dopaminergic dysfunction in schizophrenia, suggesting a rather hyperactive mesolimbic dopamine system and reduced prefrontal activation, at least in partially remitted patients treated with atypical antipsychotics.

Cognitive performance is related to cortical grey matter volumes in early stages of schizophrenia: a population-based study of first-episode psychosis

BACKGROUND

Neuropsychological deficits have been reported in association with first-episode psychosis (FEP). Reductions in grey matter (GM) volumes have been documented in FEP subjects compared to healthy controls. However, the possible inter-relationship between the findings of those two lines of research has been scarcely investigated.

OBJECTIVE

To investigate the relationship between neuropsychological deficits and GM volume abnormalities in a population-based sample of FEP patients compared to healthy controls from the same geographical area.

METHODS

FEP patients (n=88) and control subjects (n=86) were evaluated by neuropsychological assessment (Controlled Oral Word Association Test, forward and backward digit span tests) and magnetic resonance imaging using voxel-based morphometry.

RESULTS

Single-group analyses showed that prefrontal and temporo-parietal GM volumes correlated significantly (p<0.05, corrected) with cognitive performance in FEP patients. A similar pattern of direct correlations between neocortical GM volumes and cognitive impairment was seen in the schizophrenia subgroup (n=48). In the control group, cognitive performance was directly correlated with GM volume in the right dorsal anterior cingulate cortex and inversely correlated with parahippocampal gyral volumes bilaterally. Interaction analyses with "group status" as a predictor variable showed significantly greater positive correlation within the left inferior prefrontal cortex (BA46) in the FEP group relative to controls, and significantly greater negative correlation within the left parahippocampal gyrus in the control group relative to FEP patients.

CONCLUSION

Our results indicate that cognitive deficits are directly related to brain volume abnormalities in frontal and temporo-parietal cortices in FEP subjects, most specifically in inferior portions of the dorsolateral prefrontal cortex.

Apathy is associated with executive functioning in first episode psychosis

BACKGROUND

The underlying nature of negative symptoms in psychosis is poorly understood. Investigation of the relationship between the different negative subsymptoms and neurocognition is one approach to understand more of the underlying nature. Apathy, one of the subsymptoms, is also a common symptom in other brain disorders. Its association with neurocognition, in particular executive functioning, is well documented in other brain disorders, but only studied in one former study of chronic patients with schizophrenia. This study investigates the association between apathy and neurocognitive functioning in patients with first episode psychosis (FEP), with the hypothesis that apathy is more associated with tests representing executive function than tests representing other neurocognitive domains.

METHODS

Seventy-one FEP patients were assessed with an extensive neuropsychological test battery. Level of apathy was assessed with the abridged Apathy Evaluation Scale (AES-C-Apathy).

RESULTS

AES-C-Apathy was only significantly associated with tests from the executive domain [Semantic fluency (r = .37, p < .01), Phonetic fluency (r = .25, p < .05)] and working memory [Letter Number Span (r = .26; p =< .05)]; the first two representing the initiation part of executive function. Confounding variables such as co-occuring depression, positive symptoms or use of antipsychotic medication did not significantly influence the results.

CONCLUSION

We replicated in FEP patients the relationship between apathy and executive functioning reported in another study for chronic patients with schizophrenia. We also found apathy in FEP to have the same relationship to executive functioning, as assessed with the Verbal fluency tests, as that reported in patients with other brain disorders, pointing to a common underlying nature of this symptom across disorders.

The relationship between prefrontal brain volume and characteristics of memory strategy in schizophrenia spectrum disorders

The present study investigated the relationship between memory strategy use and prefrontal gray/white matter volumes of healthy control subjects, patients with schizophrenia or schizotypal disorder. Gray/white matter volumes were measured for the superior, middle, inferior, ventral medial and orbital prefrontal regions, using high-resolution magnetic resonance (MR) images that were acquired from 35 patients with schizophrenia, 25 patients with schizotypal disorder and 19 healthy subjects. Participants were also administered the Japanese Verbal Learning Test (JVLT). In control subjects, larger left inferior frontal and straight gyrus's gray matter volumes were associated with higher semantic clustering rates on the JVLT, and smaller left inferior frontal gray matter volumes were associated with higher serial clustering ratio. In schizophrenic patients, smaller left orbitofrontal gray matter volumes were associated with lower semantic clustering rates on the JVLT. In schizotypal patients, smaller left inferior frontal white matter volume was associated with smaller serial clustering rates and larger semantic clustering rate. These findings suggest that semantic organization in schizophrenic patients might depend on mobilization of a memory strategy that is mediated by orbitofrontal cortex functioning. Failure to use a semantic organization strategy might be related to reduced volume in the inferior frontal gyrus. The findings for schizotypal patients suggest a compensation mechanism to remember the words using a serial processing strategy is at work when the inferior frontal gyrus cannot mediate semantic processing.

Theory of mind and frontal lobe pathology in schizophrenia: a voxel-based morphometry study

Impaired ability to infer the mental states of others (theory of mind; ToM) is considered to be a key contributor to the poor social functioning of patients with schizophrenia. Although neuroimaging and lesion studies have provided empirical evidence for the neural basis of ToM ability, including the involvement of several prefrontal and temporal structures, the association between pathology of these structures and ToM impairment in schizophrenia patients is less well understood. To address this issue, we investigated structural brain abnormalities and ToM impairment in patients with schizophrenia, and examined the relationship between them. Twenty schizophrenia patients and 20 age-, sex- and education-matched healthy participants underwent magnetic resonance imaging (MRI) and were examined for ToM ability based on the revised version of the "Reading the Mind in the Eyes" (or Eyes) test [Baron-Cohen, S., Wheelwright, S., Hill, J., Raste, Y., Plumb, I., 2001. The 'Reading the Mind in the Eyes' test revised version: A study with normal adults, and adults with Asperger syndrome or high-functioning autism. J. Child Psychol. Psychiatry 42, 241-251]. Voxel-based morphometry (VBM) was performed to investigate regional brain alterations. Relative to normal controls, schizophrenia patients exhibited gray matter reductions in the dorsomedial prefrontal cortex (DMPFC), left ventrolateral prefrontal cortex (VLPFC), ventromedial prefrontal cortex (VMPFC), anterior cingulate cortex (ACC), right superior temporal gyrus (STG) and right insula. The patients performed poorly on the Eyes test. Importantly, poor performance on the Eyes test was found to be associated with gray matter reduction in the left VLPFC in the patient group. These results suggest that prefrontal cortical reduction, especially in the left VLPFC, is a key pathology underlying the difficulties faced by schizophrenia patients in inferring the mental states of others.

DISC1 is associated with prefrontal cortical gray matter and positive symptoms in schizophrenia

BACKGROUND

DISC1 is considered a susceptibility gene for schizophrenia and schizoaffective disorder, but little is known regarding the potential mechanisms through which it may confer increased risk. Given that DISC1 plays a role in cerebral cortex development, polymorphisms in this gene may have relevance for neurobiological models of schizophrenia that have implicated cortical deficits in its pathophysiology.

METHODS

We investigated whether the DISC1 leu607phe polymorphism was associated with prefrontal gray matter volumes using magnetic resonance imaging in a cohort of patients with schizophrenia (N=19) and healthy volunteers (N=25) and positive and negative symptoms in 200 patients with schizophrenia.

RESULTS

Among patients and healthy volunteers, phe carriers (N=11) had significantly less gray matter in the superior frontal gyrus and anterior cingulate gyrus compared to leu/leu homozygotes (N=33). Further, among patients left superior frontal gyrus gray matter volume was significantly negatively correlated with severity of hallucinations. In addition, patients who were phe carriers (N=144) had significantly greater severity of positive symptoms (hallucinations) compared to patients who were leu/leu homozygotes (N=56).

DISCUSSION

These findings implicate DISC1 in variation of prefrontal cortical volume and positive symptoms, thus providing a potential mechanism through which DISC1 may confer increased risk for schizophrenia or schizoaffective disorder.

Reward processing in schizophrenia: a deficit in the representation of value

Patients with schizophrenia demonstrate deficits in motivation and learning that suggest impairment in different aspects of the reward system. In this article, we present the results of 8 converging experiments that address subjective reward experience, the impact of rewards on decision making, and the role of rewards in guiding both rapid and long-term learning. All experiments compared the performance of stably treated outpatients with schizophrenia and demographically matched healthy volunteers. Results to date suggest (1) that patients have surprisingly normal experiences of positive emotion when presented with evocative stimuli, (2) that patients show reduced correlation, compared with controls, between their own subjective valuation of stimuli and action selection, (3) that decision making in patients appears to be compromised by deficits in the ability to fully represent the value of different choices and response options, and (4) that rapid learning on the basis of trial-to-trial feedback is severely impaired whereas more gradual learning may be surprisingly preserved in many paradigms. The overall pattern of findings suggests compromises in the orbital and dorsal prefrontal structures that play a critical role in the ability to represent the value of outcomes and plans. In contrast, patients often (but not always) approach normal performance levels on the slow learning achieved by the integration of reinforcement signals over many trials, thought to be mediated by the basal ganglia.

A cross-sectional and longitudinal magnetic resonance imaging study of cingulate gyrus gray matter volume abnormalities in first-episode schizophrenia and first-episode affective psychosis

CONTEXT

Previous magnetic resonance imaging (MRI) findings have demonstrated psychopathological symptom-related smaller gray matter volumes in various cingulate gyrus subregions in schizophrenia and bipolar disorder. However, it is unclear whether these gray matter abnormalities show a subregional specificity to either disorder and whether they show postonset progression.

OBJECTIVE

To determine whether there are initial and progressive gray matter volume deficits in cingulate gyrus subregions in patients with first-episode schizophrenia (FESZ) and patients with first-episode affective psychosis (FEAFF, mainly manic) and their specificity to FESZ or FEAFF.

DESIGN

A naturalistic cross-sectional study at first hospitalization for psychosis and a longitudinal follow-up approximately 1(1/2) years later.

SETTING AND PARTICIPANTS

Patients were from a private psychiatric hospital. Thirty-nine patients with FESZ and 41 with FEAFF at first hospitalization for psychosis and 40 healthy control subjects (HCs) recruited from the community underwent high-spatial-resolution MRI, with follow-up scans in 17 FESZ patients, 18 FEAFF patients, and 18 HCs. Individual subjects were matched for age, sex, parental socioeconomic status, and handedness.

MAIN OUTCOME MEASURES

Cingulate gyrus gray matter volumes in 3 anterior subregions (subgenual, affective, and cognitive) and 1 posterior subregion, and whether there was a paracingulate sulcus.

RESULTS

At first hospitalization, patients with FESZ showed significantly smaller left subgenual (P = .03), left (P = .03) and right (P = .005) affective, right cognitive (P = .04), and right posterior (P = .003) cingulate gyrus gray matter subregions compared with HCs. Moreover, at the 1(1/2)-year follow-up, patients with FESZ showed progressive gray matter volume decreases in the subgenual (P = .002), affective (P < .001), cognitive (P < .001), and posterior (P = .02) cingulate subregions compared with HCs. In contrast, patients with FEAFF showed only initial (left, P < .001; right, P = .002) and progressive subgenual subregion abnormalities (P < .001). Finally, patients with FESZ showed a less asymmetric paracingulate pattern than HCs (P = .02).

CONCLUSIONS

Patients with FEAFF and FESZ showed differences in initial gray matter volumes and in their progression. Initial and progressive changes in patients with FEAFF were confined to the subgenual cingulate, a region strongly associated with affective disorder, whereas patients with FESZ evinced widespread initial and progressively smaller volumes.

Surface-based morphometry of the anterior cingulate cortex in first episode schizophrenia

The anterior cingulate cortex (ACC) appears to be critically involved in the pathophysiology of schizophrenia, but past attempts at characterizing pathological changes in the region using magnetic resonance imaging have been restricted by a limited appreciation of its functional and anatomical diversity and a reliance on relatively coarse metrics (e.g., volume) to index anatomical change. In this study, we applied a novel, surface-based protocol to T1-weighted scans acquired from 40 first episode schizophrenia patients and 40 healthy controls individually matched for age, sex, and morphology of the paracingulate sulcus, a major anatomical variation that has been shown to affect morphometric estimates in the region. The surface-based approach enabled calculation of regional grey matter volume, surface area and curvature, cortical thickness, and depth of the cingulate sulcus, with sub-millimeter precision. Relative to controls, schizophrenia patients displayed a bilateral reduction in thickness of paralimbic regions of the ACC, along with a concomitant increase in surface area of both the limbic and paralimbic ACC. No differences were identified for regional grey matter volume, surface curvature, or CS depth. These findings illustrate the advantages of moving beyond traditional volume-based approaches when investigating cortical morphometry, and indicate that the early stages of schizophrenia are associated with a specific pattern of ACC abnormalities that cannot be attributed to variations in sulcal and gyral morphology.

Neuropsychological function-brain structure relationships and stage of illness: an investigation into chronic and first-episode schizophrenia

Neuropsychological function-brain structure relationships may differ as a function of illness stage because of progressive brain matter loss through the course of schizophrenia. In this study, we tested whether neuropsychological function-brain structure relationships differed as a function of illness stage. In addition, we tested whether these relationships differed between older and young healthy controls. Function-structure relationships were examined in 35 first-episode patients (31 with schizophrenia, 4 with schizoaffective disorder), 54 chronic schizophrenia patients, 21 older healthy controls and 20 young healthy controls. MRI volumes of frontal and temporal lobe structures, as well as the whole brain, were estimated using a region-of-interest approach. Hierarchical multiple regression analyses were performed between the MRI and neuropsychological measures. Stronger relationships of immediate memory-total prefrontal cortex (PFC) volume in chronic than first-episode patients, and in older than young controls were observed. The abstract reasoning (WCST perseverative errors)-total temporal lobe volume relationship was stronger in older than young controls. These function-structure relationships appeared unexplained by whole brain volume or age in chronic patients. A similar dissociation between young and older subjects of both healthy and patient groups suggests that a 'bigger-is-better' relationship style is present in older individuals regardless of a diagnosis of schizophrenia.

Neurocognitive deficits and prefrontal cortical atrophy in patients with schizophrenia

RATIONALE

Cognitive deficits are of particular importance in schizophrenia since they are strongly associated with poor prognosis. We investigated the relationship between prefrontal cortical atrophy as measured by MRI and the neuropsychological performance of participants diagnosed with DSM-IV-TR schizophrenia.

METHODS

Fourteen unmedicated adult patients and thirteen matched controls were studied. Subjects underwent MRI yielding 1 mm isotropic T1-weighted images. Voxel based morphometry was applied to all images using SPM5. The mean gray level of Brodmann area (BA) 9 was also extracted and evaluated using simple regression along with relative score differences on patients neuropsychological tests compared to controls.

RESULTS

Patients exhibited a poorer performance on the Controlled Word Association Task (COWAT), Wisconsin Card Sorting Test (WCST) and Trail Making Test (TMT). Patients also presented a greater level of apathy as indexed by the Apathy Evaluation Scale (AES). There was a significant decrease in gray matter volume in patients with schizophrenia in left supplementary motor area, bilateral superior frontal gyrus, left middle frontal gyrus, right opercular area, left angular gyrus, left superior temporal gyrus and left cerebellar hemisphere. Within the schizophrenia group, decreased BA9 gray matter volume was correlated with poorer performance on the WCST and TMT-B.

CONCLUSION

Prefrontal gray matter abnormalities in schizophrenia patients may be associated with some symptoms including difficulties with set-shifting and decreased mental flexibility. Further studies evaluating prefrontal connectivity may clarify if such impairment results from abnormalities of the frontal area alone, or are a result of altered networks involving the frontal and extra-frontal areas.

Neuropsychological functioning and brain structure in schizophrenia

Cognitive deficits are core features of schizophrenia that are already evident at early phases of the illness. The study of specific relationships between cognition and brain structure might provide valuable clues about neural basis of schizophrenia and its phenomenology. The aim of this article was to review the most consistent findings of the studies exploring the relationships between cognitive deficits and brain anomalies in schizophrenia. Besides several important methodological shortcomings to bear in mind before drawing any consistent conclusion from the revised literature, we have attempted to systematically summarize these findings. Thus, this review has revealed that whole brain volume tends to positively correlate with a range of cognitive domains in healthy volunteers and female patients. An association between prefrontal morphological characteristics and general inability to control behaviour seems to be present in schizophrenia patients. Parahippocampal volume is related to semantic cognitive functions. Thalamic anomalies have been associated with executive deficits specifically in patients. Available evidence on the relationship between cognitive functions and cerebellar structure is still contradictory. Nonetheless, a larger cerebellum appears to be associated with higher IQ in controls and in female patients. Enlarged ventricles, including lateral and third ventricles, are associated with deficits in attention, executive and premorbid cognitive functioning in patients. Several of these reported findings seem to be counterintuitive according to neural basis of cognitive functioning drawn from animal, lesion, and functional imaging investigations. Therefore, there is still a great need for more methodologically stringent investigations that would help in the advance of our understanding of the cognition/brain structure relationships in schizophrenia.

Prefrontal-thalamic-cerebellar gray matter networks and executive functioning in schizophrenia

OBJECTIVE

Poor executive functioning is a core deficit in schizophrenia and has been linked to frontal lobe alterations. We aimed to identify (1) prefrontal cerebral areas in which decreased volume is linked to executive dysfunction in schizophrenia; and (2) areas throughout the brain that are volumetrically related to the prefrontal area identified in the first analysis, thus detecting more extended volumetric networks associated with executive functioning.

METHOD

Fifty-three outpatients with schizophrenia and 62 healthy controls, matched for age, gender and handedness, were recruited. High-resolution images were acquired on a 1.5 tesla scanner and regional gray and white matter volumes were analyzed by voxel-based morphometry within SPM5 (statistical parametric mapping, University College London, UK). Executive functioning was assessed using the Wisconsin Card Sorting Test (WCST).

RESULTS

Twenty-one patients with poor executive functioning showed reduced dorsolateral prefrontal and anterior cingulate gray matter volume as compared to 30 patients with high WCST performance, with a maximum effect in the left dorsolateral prefrontal cortex. Left dorsolateral prefrontal gray matter volume predicted WCST performance after controlling for possible confounding effects of global cognitive functioning, verbal attention span, negative symptoms, illness duration and education. In this area, both patient groups had less gray matter than healthy controls. Left dorsolateral prefrontal gray matter volume was positively related to dorsal prefrontal, anterior cingulate and parietal gray matter volume; and negatively related to thalamic, cerebellar, pontine and right parahippocampal gray matter volume.

CONCLUSIONS

Volumetric alterations in prefrontal-thalamic-cerebellar gray matter networks may lead to executive dysfunction in schizophrenia.

Anterior cingulate pathology and social cognition in schizophrenia: a study of gray matter, white matter and sulcal morphometry

The anterior cingulate gyrus (ACG) is a critical structure for social cognitive processing; the pathology of this structure might be a major source of social dysfunction in schizophrenia. Multiple structural abnormalities of the ACG have been demonstrated in schizophrenia including changes in gray matter volume, white matter microstructures and macroscopic sulcal morphology. However, the interrelationships among these different abnormalities have not been investigated. Thus, the relationship between structural abnormalities in the ACG and social cognition in schizophrenia remains to be elucidated. Magnetic resonance imaging data were acquired at 3.0 T from 26 schizophrenic patients and 20 healthy participants. We performed anterior cingulate cortex (ACC) volumetry, evaluated diffusion tensor imaging of the anterior cingulum, analyzed paracingulate/cingulate sulcus (PCS/CS) morphology and investigated the interrelationships among these measures. We also investigated the association between ACG structural abnormalities and psychopathology, and the social cognition ability of schizophrenic patients as estimated by emotion attribution tasks. Compared with healthy subjects, schizophrenic patients exhibited reduced ACC volume, decreased fractional anisotropy in the anterior cingulum bilaterally and a poorly developed PCS/CS in the left hemisphere. No interrelationship was identified among these measures in the schizophrenic group. Schizophrenic patients performed poorly on emotion attribution tasks. Importantly, clinical symptoms and performance on emotion attribution subtasks were associated with ACC volumes and left PCS/CS variation in different ways. These results suggested that pathology of the ACC, anterior cingulum and PCS/CS is, at least partially, independent and has differential impacts on psychopathology and social cognitive impairment in schizophrenia.