Regional changes in brain gray and white matter in patients with schizophrenia demonstrated with voxel-based analysis of MRI

Age-related changes in regional brain volume evaluated by atlas-based method

INTRODUCTION

The effects of aging on brain volume are generally investigated using voxel-based morphometry (VBM) or the manually traced region-of-interest (ROI) method. We introduce an atlas-based method as a methodological alternative that calculates absolute volume as a non-biased and semi-automatic whole-brain technique.

METHODS

We enrolled 115 healthy females (mean age, 36.7 years) and 130 healthy males (mean age, 37.1 years). Volume data were acquired using a 1.5 tesla magnetic resonance scanner. After spatial normalization, a lobar-based atlas template was applied, and the absolute volumes of the frontal, temporal, parietal, and occipital lobes and the sublobar and limbic areas were calculated bilaterally. The effects of age on regional brain volume were evaluated statistically.

RESULTS

The volume of all ROIs declined linearly with increasing age. The bilateral frontal lobes showed the steepest involution. Analysis of variance revealed significant laterality and interaction of gender and age.

CONCLUSION

The atlas-based method introduced in the present study has advantages over the manually traced ROI method in its objectivity, coverage, and time requirement and has an advantage over the VBM method in its computability of absolute volume. The results are largely in agreement with those reported previously, thereby reconfirming the importance of matching gender and age in analyzing brain disorders.

White matter reduction in patients with schizophrenia as revealed by voxel-based morphometry: an activation likelihood estimation meta-analysis

Schizophrenia is thought to be a mental disorder caused by the disconnection of brain regions. Cumulative evidence of white matter deficit in patients with schizophrenia has been reported using voxel-based morphometry (VBM), but these studies have not been quantitatively reviewed. In the study reported herein, we used activation likelihood estimation (ALE) analysis to quantitatively estimate focal white matter abnormalities in patients with schizophrenia. Seventeen studies that compared the white matter deficit of patients with schizophrenia and healthy controls were ascertained. The frontal white matter regions and internal capsule revealed consistent white matter reduction in patient groups relative to healthy controls, suggesting a clear focal white matter deficit in patients with schizophrenia. These results support the macro-circuit theory of white matter change in schizophrenia.

An MRI study of the superior temporal subregions in first-episode patients with various psychotic disorders

Morphologic abnormalities of the superior temporal gyrus (STG) have been reported in schizophrenia, but have not been extensively studied in other psychotic disorders such as affective psychosis. In the present study, magnetic resonance imaging was used to examine the volumes of the STG and its subregions [planum polare (PP), Heschl gyrus (HG), planum temporale (PT), rostral STG, and caudal STG] in 162 first-episode patients with various psychotic disorders [46 schizophrenia (31 schizophrenia and 15 schizoaffective disorder), 57 schizophreniform disorder, 34 affective psychosis, and 25 other psychoses] and 62 age- and sex-matched healthy controls. The first-episode schizophrenia patients had significantly less gray matter in HG, PT, and caudal STG bilaterally compared with all other groups, but there was no difference between the controls and affective psychosis, schizophreniform disorder, or other psychoses for any STG subregion. The STG white matter volume did not differ between groups. Our findings indicate that morphologic abnormalities of the STG gray matter are specific to schizophrenia among various psychotic disorders, implicating its role in the underlying pathophysiology of schizophrenia.

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.

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.

Progressive gray matter reduction of the superior temporal gyrus during transition to psychosis

CONTEXT

Longitudinal magnetic resonance imaging studies have shown progressive gray matter reduction in the superior temporal gyrus during the earliest phases of schizophrenia. It is unknown whether these progressive processes predate the onset of psychosis.

OBJECTIVE

To examine gray matter reduction of the superior temporal gyrus over time in individuals at risk for psychosis and in patients with first-episode psychosis.

DESIGN

Cross-sectional and longitudinal comparisons.

SETTING

Personal Assessment and Crisis Evaluation Clinic and Early Psychosis Preventions and Intervention Centre.

PARTICIPANTS

Thirty-five ultrahigh-risk individuals (of whom 12 later developed psychosis [UHRP] and 23 did not [UHRNP]), 23 patients with first-episode psychosis (FEP), and 22 control subjects recruited from the community.

MAIN OUTCOME MEASURES

Volumes of superior temporal subregions (planum polare, Heschl gyrus, planum temporale, and rostral and caudal regions) were measured at baseline and follow-up (mean, 1.8 years) and were compared across groups.

RESULTS

In cross-sectional comparisons, only the FEP group had significantly smaller planum temporale and caudal superior temporal gyrus than other groups at baseline, whereas male UHRP subjects also had a smaller planum temporale than controls at follow-up. In longitudinal comparison, UHRP and FEP patients showed significant gray matter reduction (approximately 2%-6% per year) in the planum polare, planum temporale, and caudal region compared with controls and/or UHRNP subjects. The FEP patients also exhibited progressive gray matter loss in the left Heschl gyrus (3.0% per year) and rostral region (3.8% per year), which were correlated with the severity of delusions at follow-up.

CONCLUSIONS

A progressive process in the superior temporal gyrus precedes the first expression of florid psychosis. These findings have important implications for underlying neurobiologic features of emerging psychotic disorders and emphasize the importance of early intervention during or before the first episode of psychosis.

Application of a multifractal analysis to study brain white matter abnormalities of schizophrenia on T2-weighted magnetic resonance imaging

Multifractal analysis provides a precise quantitative description of the structural complexity of white matter (WM) on magnetic resonance imaging (MRI). To test this new technique as an aid to elucidating the pathology of schizophrenia, we examined a multifractal dimension (i.e. Deltaalpha) of WM in schizophrenia patients and their relations to clinical variables. We examined 16 patients with schizophrenia and 16 controls matched for age, sex and handedness. Delta alpha value of WM in the prefrontal and frontoparietal lobes and the corpus callosum (genu and splenium) on T2-weighted MRI was calculated. Delta alpha was not significantly different between groups in either region of interest. However, group-by-side interaction for Deltaalpha was found in the frontoparietal WM; post-hoc analysis revealed normal left dominant asymmetry in Deltaalpha for frontoparietal WM in control subjects, which was absent in schizophrenia patients. Furthermore, the patients with schizophrenia had a lower asymmetry coefficient ([R-L]/[R+L]) for Deltaalpha in frontoparietal WM. Relations to clinical symptoms from the Positive and Negative Syndrome Scale, Deltaalpha in corpus callosum, and the asymmetry coefficient in prefrontal WM were correlated with negative and general psychopathology symptom scores. Our results support the left-sided dysfunction hypothesis of schizophrenia and its relation to schizophrenic symptoms. Multifractal analysis reveals abnormal patterns of WM structures in schizophrenia that could be implicated in the disorder's etiology.

Mapping grey matter reductions in schizophrenia: an anatomical likelihood estimation analysis of voxel-based morphometry studies

Voxel-based morphometry (VBM) is a popular tool for mapping neuroanatomical changes in schizophrenia patients. Several recent meta-analyses have identified the brain regions in which patients most consistently show grey matter reductions, although they have not examined whether such changes reflect differences in grey matter concentration (GMC) or grey matter volume (GMV). These measures assess different aspects of grey matter integrity, and may therefore reflect different pathological processes. In this study, we used the Anatomical Likelihood Estimation procedure to analyse significant differences reported in 37 VBM studies of schizophrenia patients, incorporating data from 1646 patients and 1690 controls, and compared the findings of studies using either GMC or GMV to index grey matter differences. Analysis of all studies combined indicated that grey matter reductions in a network of frontal, temporal, thalamic and striatal regions are among the most frequently reported in literature. GMC reductions were generally larger and more consistent than GMV reductions, and were more frequent in the insula, medial prefrontal, medial temporal and striatal regions. GMV reductions were more frequent in dorso-medial frontal cortex, and lateral and orbital frontal areas. These findings support the primacy of frontal, limbic, and subcortical dysfunction in the pathophysiology of schizophrenia, and suggest that the grey matter changes observed with MRI may not necessarily result from a unitary pathological process.

White matter abnormalities in bipolar disorder and schizophrenia detected using diffusion tensor magnetic resonance imaging

OBJECTIVES

Strong qualitative and quantitative evidence exists of white matter abnormalities in both schizophrenia and bipolar disorder (BD). Diffusion tensor imaging (DTI) studies suggest altered connectivity in both disorders. We aim to address the diagnostic specificity of white matter abnormalities in these disorders.

METHODS

DTI was used to assess white matter integrity in clinically stable patients with familial BD (n = 42) and familial schizophrenia (n = 28), and in controls (n = 38). Differences in fractional anisotropy (FA) were measured using voxel-based morphometry and automated region of interest analysis.

RESULTS

Reduced FA was found in the anterior limb of the internal capsule (ALIC), anterior thalamic radiation (ATR), and in the region of the uncinate fasciculus in patients with BD and those with schizophrenia compared with controls. A direct comparison between patient groups found no significant differences in these regions. None of the findings were associated with psychotropic medication.

CONCLUSIONS

Reduced integrity of the ALIC, uncinate fasciculus, and ATR regions is common to both schizophrenia and BD. These results imply an overlap in white matter pathology, possibly relating to risk factors common to both disorders.

Increased grey matter densities in schizophrenia patients with negative symptoms after treatment with quetiapine: a voxel-based morphometry study

Among new-generation antipsychotics, quetiapine was found to be associated with a partial 'normalization' of reduced functional activation in prefrontal and temporal areas and studies conducted by our group found a clinical improvement in negative symptoms in addition to restoration of frontal activation in schizophrenia patients with blunted affect after treatment with quetiapine. Here we investigated the parallelism between improved clinical symptoms and grey mater density (GMD) changes in the frontal region after quetiapine treatment in 15 schizophrenia patients. We hypothesize that improvement in clinical symptoms will be associated with change in GMD in prefrontal regions of interest. By using voxel-based morphometry, paired t-test random-effect analysis showed a significant increase in GMD bilaterally in the inferior frontal cortex/orbitofrontal gyrus and anterior cingulate cortex after 5.5 months of treatment with quetiapine. This GMD increase was associated with a significant improvement in negative symptoms. When GMD was correlated with psychiatric assessment scores, there was a negative correlation between GMD in the anterior cingulate cortex and the Rating Scale for Emotional Blunting score (r=-665, P=0.008) and between the orbitofrontal gyrus and the total Positive and Negative Syndrome Scale negative score (r=-764, P=0.001). Results suggest that increased GMD in some frontal regions are associated with an improvement of negative symptoms. Although not unique to quetiapine, it would be reasonable to attribute the GMD changes in the study to treatment.

Effects of social isolation rearing on the limbic brain: a combined behavioral and magnetic resonance imaging volumetry study in rats

Rearing rats in social isolation from weaning induces robust behavioral and neurobiological alterations resembling some of the core symptoms of schizophrenia, such as reduction in prepulse inhibition of acoustic startle (PPI) and locomotor hyperactivity in a novel arena. The aim of this study was to investigate whether social isolation rearing induces volumetric remodeling of the limbic system, and to probe for anatomical structure-behavioral interrelations. Isolation- (n=8) and group-reared (n=8) rats were examined by magnetic resonance (MR) volumetry using high-resolution T2-weighted imaging at 7 T. Volumes of medial prefrontal cortex (mPFC), anterior cingulate cortex (ACC), retrosplenial cortex (RSC) and hippocampal formation were compared between groups and with behavioral measures, i.e. PPI and locomotor activity in a novel arena. Isolation rearing induced locomotor hyperactivity and impaired PPI compared with group-housed rats. The right mPFC was significantly reduced (5.4%) in isolation-reared compared with group-reared rats, with a similar trend on the left side (5.2%). mPFC volumes changes were unrelated to behavioral abnormalities. No significant volume changes were observed in ACC, RSC or hippocampal formation. Hippocampal volumes were associated with the magnitude of PPI response in control but not in isolation-reared rats. Rearing rats in social isolation induced remodeling of the limbic brain with selective prefrontal cortex volume loss. In addition, a dissociation of the interrelation between hippocampal volume and PPI was noted in the isolation-reared rats. Taken together, limbic morphometry is sensitive to the effects of social isolation rearing but did not reveal direct brain-behavior interrelations, calling for more detailed circuitry analysis.

Meta-analysis of gray matter anomalies in schizophrenia: application of anatomic likelihood estimation and network analysis

BACKGROUND

Although structural neuroimaging methods have been widely used to study brain morphology in schizophrenia, synthesizing this literature has been difficult. With the increasing popularity of voxel-based morphometric (VBM) methods in which group differences are reported in standardized coordinates, it is possible to apply powerful meta-analytic techniques initially designed for functional neuroimaging. In this study, we performed a voxelwise, coordinate-based meta-analysis to better conceptualize the neuroanatomic correlates of schizophrenia.

METHODS

Thirty-one peer-reviewed articles, with a total of 1195 patients with schizophrenia contrasted with 1262 healthy volunteers, were included in the meta-analysis. Coordinates from each article were used to create a statistical map that estimated the likelihood of between-group gray matter density differences at every brain voxel. These results were subsequently entered into a network analysis.

RESULTS

Patients had reduced gray matter density relative to control subjects in a distributed network of regions, including bilateral insular cortex, anterior cingulate, left parahippocampal gyrus, left middle frontal gyrus, postcentral gyrus, and thalamus. Network analysis grouped these regions into four distinct networks that potentially represent different pathologic processes. Patients had increased gray matter density in striatal regions.

CONCLUSIONS

This study expands on previous meta-analyses of the neuroanatomy of schizophrenia by elucidating a series of brain networks disrupted by the illness. Because it is possible that these networks are influenced by independent etiologic factors, this work should foster more detailed neural models of the illness and focus research designed to discover the mechanisms of gray matter reduction in schizophrenia.

Developmental disruptions in neural connectivity in the pathophysiology of schizophrenia

Schizophrenia has been thought of as a disorder of reduced functional and structural connectivity. Recent advances in neuroimaging techniques such as functional magnetic resonance imaging, structural magnetic resonance imaging, diffusion tensor imaging, and small animal imaging have advanced our ability to investigate this hypothesis. Moreover, the power of longitudinal designs possible with these noninvasive techniques enable the study of not just how connectivity is disrupted in schizophrenia, but when this disruption emerges during development. This article reviews genetic and neurodevelopmental influences on structural and functional connectivity in human populations with or at risk for schizophrenia and in animal models of the disorder. We conclude that the weight of evidence across these diverse lines of inquiry points to a developmental disruption of neural connectivity in schizophrenia and that this disrupted connectivity likely involves susceptibility genes that affect processes involved in establishing intra- and interregional connectivity.

Female specific anterior cingulate abnormality and its association with empathic disability in schizophrenia

Evidence suggests that impairments of empathy are present in schizophrenia and that such deficits lead to social dysfunction. However, the relationship between brain morphological abnormalities of the disorder and empathic disabilities has not been fully investigated. As the anterior cingulate cortex (ACC) is one of the critical structures for empathy processing, the pathology of this structure might be a major source of social dysfunction, including interpersonal miscommunication in schizophrenia. In addition, as recent studies suggest that different facets of empathic ability depend on different subdivisions of the ACC, pathology of each subdivision would affect the empathic disability of schizophrenia differentially. Structural MRI data were acquired at 3.0 T from 24 schizophrenic patients and 20 healthy participants, and the volumes of ventral and dorsal ACC were measured and compared between the groups. Subjects' empathic abilities were evaluated using a multidimensional questionnaire, the Interpersonal Reactivity Index (IRI). The relationships of structural abnormalities with empathic disabilities were investigated, by correlating ACC subdivisional volumes with each IRI subscale score. Female schizophrenic patients exhibited volume reductions in the ventral ACC bilaterally and in the left dorsal ACC compared with healthy subjects. Schizophrenic patients performed poorly on fantasy and personal distress subscales of the IRI. Furthermore, volumes of the left dorsal ACC were inversely correlated with personal distress subscale scores within female patients with schizophrenia. These results suggest that pathology of specific ACC subdivisions would have an impact on specific empathic disabilities in schizophrenia, with potential gender specificity.

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.

The anatomy of first-episode and chronic schizophrenia: an anatomical likelihood estimation meta-analysis

OBJECTIVE

The authors sought to map gray matter changes in first-episode schizophrenia and to compare these with the changes in chronic schizophrenia. They postulated that the data would show a progression of changes from hippocampal deficits in first-episode schizophrenia to include volume reductions in the amygdala and cortical gray matter in chronic schizophrenia.

METHOD

A systematic search was conducted for voxel-based structural MRI studies of patients with first-episode schizophrenia and chronic schizophrenia in relation to comparison groups. Meta-analyses of the coordinates of gray matter differences were carried out using anatomical likelihood estimation. Maps of gray matter changes were constructed, and subtraction meta-analysis was used to compare them.

RESULTS

A total of 27 articles were identified for inclusion in the meta-analyses. A marked correspondence was observed in regions affected by both first-episode schizophrenia and chronic schizophrenia, including gray matter decreases in the thalamus, the left uncus/amygdala region, the insula bilaterally, and the anterior cingulate. In the comparison of first-episode schizophrenia and chronic schizophrenia, decreases in gray matter volume were detected in first-episode schizophrenia but not in chronic schizophrenia in the caudate head bilaterally; decreases were more widespread in cortical regions in chronic schizophrenia.

CONCLUSIONS

Anatomical changes in first-episode schizophrenia broadly coincide with a basal ganglia-thalamocortical circuit. These changes include bilateral reductions in caudate head gray matter, which are absent in chronic schizophrenia. Comparing first-episode schizophrenia and chronic schizophrenia, the authors did not find evidence for the temporolimbic progression of pathology from hippocampus to amygdala, but there was evidence for progression of cortical changes.

White matter alterations in schizophrenic patients with pronounced negative symptomatology and with positive family history for schizophrenia

BACKGROUND

In recent years, in vivo and post-mortem studies detected structural brain changes in schizophrenia. The aim of our analysis was to investigate potential changes of white matter in schizophrenic patients compared to controls, and the relationship to clinical characteristics.

METHODS

Fifty male, right-handed schizophrenic patients who met DSM-IV criteria for schizophrenia were recruited. Fifty right-handed, age- and sex-matched subjects without a psychiatric disorder were enrolled as controls. Volumes of white matter in several brain regions were measured by 1.5 T MRI using a volumetry and segmentation software (BRAINS). Regions of interest including frontal, temporal, parietal, occipital and subcortical areas were determined using Talairach spaces.

RESULTS

No significant differences in white matter volumes of total brain tissue and regions of interest were detected between patients and controls. A significant reduction of white matter in parietal cortex of right hemisphere was found in a subgroup of patients with pronounced negative symptoms. Furthermore, patients with first-grade relatives suffering from schizophrenia showed a reduction of subcortical white matter in the right hemisphere.

CONCLUSIONS

Our results indicate that subgroups of schizophrenic patients show alterations of white matter in distinct brain regions, including the right parietal lobe.

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.

Anomalous cerebral asymmetry in patients with schizophrenia demonstrated by voxel-based morphometry

BACKGROUND

Evaluating cerebral asymmetry in schizophrenia patients potentially leads to understanding the extent to which the disorder involves a neurodevelopmental failure. We sought to clarify in which brain regions of the patient the normal cerebral asymmetry is disrupted and the extent of disruption.

METHODS

Voxel-based morphometry to evaluate gray matter asymmetry was carried out with magnetic resonance images from a total of 120 right-handed subjects. They comprised four groups of 30 subjects (i.e., male schizophrenia, female schizophrenia, male control, and female control). To examine gray matter asymmetry we generated images of the lateralization index.

RESULTS

The analysis within each of four groups revealed a consistent pattern of gray matter asymmetry over all groups. However group comparison between all patients and all healthy subjects showed significant difference in the cerebral lateralization in the pars triangularis and planum temporale. Frequency distributions of the lateralization index showed a skew toward rightward asymmetry in the pars trianglaris and a reduction in leftward asymmetry in the planum temporale in patients relative to control subjects.

CONCLUSIONS

A disturbance of cerebral asymmetry in schizophrenia was suggested to be present in language-related regions, which might reflect a perturbation in the lateralization process underlying left cerebral dominance for language.

A large scale (N=400) investigation of gray matter differences in schizophrenia using optimized voxel-based morphometry

BACKGROUND

Many studies have employed voxel-based morphometry (VBM) of MRI images as an automated method of investigating cortical gray matter differences in schizophrenia. However, results from these studies vary widely, likely due to different methodological or statistical approaches.

OBJECTIVE

To use VBM to investigate gray matter differences in schizophrenia in a sample significantly larger than any published to date, and to increase statistical power sufficiently to reveal differences missed in smaller analyses.

METHODS

Magnetic resonance whole brain images were acquired from four geographic sites, all using the same model 1.5T scanner and software version, and combined to form a sample of 200 patients with both first episode and chronic schizophrenia and 200 healthy controls, matched for age, gender and scanner location. Gray matter concentration was assessed and compared using optimized VBM.

RESULTS

Compared to healthy controls, schizophrenia patients showed significantly less gray matter concentration in multiple cortical and subcortical regions, some previously unreported. Overall, we found lower concentrations of gray matter in regions identified in prior studies, most of which reported only subsets of the affected areas.

CONCLUSIONS

Gray matter differences in schizophrenia are most comprehensively elucidated using a large, diverse and representative sample.

Evidence for acquired pregenual anterior cingulate gray matter loss from a twin study of combat-related posttraumatic stress disorder

BACKGROUND

Controversy exists over the nature and origin of reduced regional brain volumes in posttraumatic stress disorder (PTSD). At issue is whether these reductions represent preexisting vulnerability factors for developing PTSD upon traumatic exposure or acquired PTSD signs due to the traumatic stress that caused the PTSD or the chronic stress of having the disorder (or both). We employed a case-control design in monozygotic twin pairs discordant for combat exposure to address the preexisting versus acquired origin of brain morphometric abnormalities in PTSD.

METHODS

We used voxel-based morphometry to search for gray matter density reductions in magnetic resonance imaging (MRI) data obtained in a previous study of combat-exposed Vietnam veteran twins with (n = 18) versus without (n = 23) PTSD and their "high-risk" versus "low-risk" (respectively) identical combat-unexposed cotwins.

RESULTS

Compared with the combat-exposed twins without PTSD, the combat-exposed twins with PTSD showed significant gray matter density reductions in four predicted brain regions: right hippocampus, pregenual anterior cingulate cortex (ACC), and left and right insulae. There was a significant PTSD Diagnosis x Combat Exposure interaction in pregenual ACC in which combat-exposed PTSD twins had lower gray matter density than their own combat-unexposed cotwins as well as than the combat-exposed twins without PTSD and their cotwins.

CONCLUSIONS

The results point to gray matter volume diminutions in limbic and paralimbic structures in PTSD. The pattern of results obtained for pregenual ACC suggests that gray matter reduction in this region represents an acquired sign of PTSD consistent with stress-induced loss.

Gray matter volume differences and the effects of smoking on gray matter in schizophrenia

OBJECTIVE

Many studies have evaluated differences in gray matter volume in schizophrenia, but have not considered the possible effects of smoking, which is extraordinarily common in people with the illness. The present study used voxel-based morphometry (VBM) to examine differences in gray matter in subjects with schizophrenia and evaluate the effects of smoking on this measure.

METHODS

Thirty-two subjects with schizophrenia (14 smokers, 18 non-smokers) and 32 healthy comparison subjects participated in the study. Whole brain, voxel-wise analyses of regional gray matter volume were conducted using voxel-based morphometry (VBM).

RESULTS

Reduced gray matter was observed in the schizophrenia group in the orbitofrontal cortex, bilateral insula and superior temporal gyri (STG), bilateral dorsolateral prefrontal cortices (DLPFC), medial frontal gyrus, and cingulate gyrus. Within this group, smoking subjects had greater lateral prefrontal and STG gray matter volumes relative to non-smoking subjects.

CONCLUSIONS

The finding of reduced gray matter volume in prefrontal and temporal regions in schizophrenia is consistent with prior anatomical tracing and whole-brain voxel-based studies. Greater gray matter volumes in smoking relative to non-smoking subjects with schizophrenia highlight a potential experimental confound in volumetric studies and suggests that smoking may be associated with a relative preservation of lateral prefrontal and temporal gray matter in schizophrenia.

White matter abnormalities associated with auditory hallucinations in schizophrenia: a combined study of voxel-based analyses of diffusion tensor imaging and structural magnetic resonance imaging

White matter (WM) abnormalities in schizophrenia may offer important clues to a better understanding of the disconnectivity associated with the disorder. The aim of this study was to elucidate a WM basis of auditory hallucinations in schizophrenia through the simultaneous investigation of WM tract integrity and WM density. Diffusion tensor images (DTIs) and structural T1 magnetic resonance images (MRIs) were taken from 15 hallucinating schizophrenic patients, 15 non-hallucinating schizophrenic patients and 22 normal controls. Voxel-based analyses and post-hoc region of interest analyses were obtained to compare the three groups on fractional anisotropy (FA) derived from DTI as well as WM density derived from structural MRIs. In both the hallucinating and non-hallucinating groups, FA of the WM regions was significantly decreased in the left superior longitudinal fasciculus (SLF), whereas WM density was significantly increased in the left inferior longitudinal fasciculus (ILF). The mean FA value of the left frontal part of the SLF was positively correlated with the severity score of auditory hallucinations in the hallucinating patient group. Our findings show that WM changes were mainly observed in the frontal and temporal areas, suggesting that disconnectivity in the left fronto-temporal area may contribute to the pathophysiology of schizophrenia. In addition, pathologic WM changes in this region may be an important step in the development of auditory hallucinations in schizophrenia.

Dysconnection topography in schizophrenia revealed with state-space analysis of EEG

Background

The dysconnection hypothesis has been proposed to account for pathophysiological mechanisms underlying schizophrenia. Widespread structural changes suggesting abnormal connectivity in schizophrenia have been imaged. A functional counterpart of the structural maps would be the EEG synchronization maps. However, due to the limits of currently used bivariate methods, functional correlates of dysconnection are limited to the isolated measurements of synchronization between preselected pairs of EEG signals.

Methods/Results

To reveal a whole-head synchronization topography in schizophrenia, we applied a new method of multivariate synchronization analysis called S-estimator to the resting dense-array (128 channels) EEG obtained from 14 patients and 14 controls. This method determines synchronization from the embedding dimension in a state-space domain based on the theoretical consequence of the cooperative behavior of simultaneous time series—the shrinking of the state-space embedding dimension. The S-estimator imaging revealed a specific synchronization landscape in schizophrenia patients. Its main features included bilaterally increased synchronization over temporal brain regions and decreased synchronization over the postcentral/parietal region neighboring the midline. The synchronization topography was stable over the course of several months and correlated with the severity of schizophrenia symptoms. In particular, direct correlations linked positive, negative, and general psychopathological symptoms to the hyper-synchronized temporal clusters over both hemispheres. Along with these correlations, general psychopathological symptoms inversely correlated within the hypo-synchronized postcentral midline region. While being similar to the structural maps of cortical changes in schizophrenia, the S-maps go beyond the topography limits, demonstrating a novel aspect of the abnormalities of functional cooperation: namely, regionally reduced or enhanced connectivity.

Conclusion/Significance

The new method of multivariate synchronization significantly boosts the potential of EEG as an imaging technique compatible with other imaging modalities. Its application to schizophrenia research shows that schizophrenia can be explained within the concept of neural dysconnection across and within large-scale brain networks.

Reduced microstructural integrity of the white matter underlying anterior cingulate cortex is associated with increased saccadic latency in schizophrenia

The anterior cingulate cortex (ACC) is a key component of a network that directs both spatial attention and saccadic eye movements, which are tightly linked. Diffusion tensor imaging (DTI) has demonstrated reduced microstructural integrity of the anterior cingulum bundle as indexed by fractional anisotropy (FA) in schizophrenia, but the functional significance of these abnormalities is unclear. Using DTI, we examined the white matter underlying anterior cingulate cortex in schizophrenia to determine whether reduced FA is associated with prolonged latencies of volitional saccades. Seventeen chronic, medicated schizophrenia outpatients and nineteen healthy controls had high-resolution DTI scans. FA maps were registered to structural scans and mapped across participants using a surface-based coordinate system. Cingulate white matter was divided into rostral and dorsal anterior regions and a posterior region. Patients showed reduced FA in cingulate white matter of the right hemisphere. Reduced FA in the white matter underlying anterior cingulate cortex, frontal eye field, and posterior parietal cortex of the right hemisphere was associated with longer saccadic latencies in schizophrenia, though given the relatively small sample size, these relations warrant replication. These findings demonstrate that in schizophrenia, increased latency of volitional saccades is associated with reduced microstructural integrity of the white matter underlying key cortical components of a right-hemisphere dominant network for visuospatial attention and ocular motor control. Moreover, they suggest that anterior cingulate white matter abnormalities contribute to slower performance of volitional saccades and to inter-individual variability of saccadic latency in chronic, medicated schizophrenia.

Anterior cingulate volumes in schizophrenia: a systematic review and a meta-analysis of MRI studies

OBJECTIVES

Several MRI studies have investigated the anterior cingulate in schizophrenia, as this is a key region for emotional processing and higher executive performances. A systematic review of structural MRI studies and a meta-analysis were conducted to explore whether anterior cingulate volumes are abnormal in patients with schizophrenia.

METHOD

A systematic search strategy was used to identify eligible MRI studies. Thereafter, a meta-analysis was carried out by using a random effect model. Also, a meta-regression analysis was used to assess the influence of age, gender and slice thickness on effect sizes.

RESULTS

The meta-analysis was performed on seven studies. These results showed that the anterior cingulate volumes were significantly reduced in patients compared to healthy controls. Significant heterogeneity between these studies was observed. The meta-regression demonstrated that the effect size was significantly related only to slice thickness.

CONCLUSIONS

Our work confirmed the presence of abnormally reduced anterior cingulate volumes in schizophrenia. However, several methodological issues limited the interpretation of these findings. Among these were different MR acquisition parameters and the small size of the sample, which was mostly composed of chronic patients. Future MRI studies should be planned to better understand the functional expression of anterior cingulate structural abnormalities.

A comprehensive assessment of gray and white matter volumes and their relationship to outcome and severity in schizophrenia

Preliminary data suggest an association of posterior cortical gray matter reduction with poor outcome in schizophrenia. We made a systematic MRI assessment of regional gray and white matter volumes, parcellated into 40 Brodmann's areas, in 104 patients with schizophrenia (51 with good outcomes, 53 with poor outcomes) and 41 normal comparison subjects, and investigated correlations of regional morphometry with outcome and severity of the illness. Schizophrenia patients displayed differential reductions in frontal and to a lesser degree temporal gray matter volumes in both hemispheres, most pronounced in the frontal pole and lateral temporal cortex. White matter volumes in schizophrenia patients were bilaterally increased, primarily in the frontal, parietal, and isolated temporal regions, with volume reductions confined to anterior cingulate gyrus. In patients with schizophrenia as a group, higher illness severity was associated with reduced temporal gray matter volumes and expanded frontal white matter volumes in both hemispheres. In comparison to good-outcome group, patients with poor outcomes had lower temporal, occipital, and to a lesser degree parietal gray matter volumes in both hemispheres and temporal, parietal, occipital, and posterior cingulate white matter volumes in the right hemisphere. While gray matter deficits in the granular cortex were observed in all schizophrenia patients, agranular cortical deficits in the left hemisphere were peculiar to patients with poor outcomes. These results provide support for frontotemporal gray matter reduction and frontoparietal white matter expansion in schizophrenia. Poor outcome is associated with more posterior distribution (posteriorization) of both gray and white matter changes, and with preferential impairment in the unimodal visual and paralimbic cortical regions.

Internal capsule, corpus callosum and long associative fibers in good and poor outcome schizophrenia: a diffusion tensor imaging survey

BACKGROUND

Prior voxelwise studies of white matter anisotropy found widespread reductions involving all major fiber tracts of the schizophrenic brain. We set out to confirm these exploratory findings and evaluate their relation to illness severity using a hypothesis-driven region-of-interest approach.

METHODS

104 schizophrenia patients (51 with good outcomes, 53 with poor outcomes) and 41 matched comparison subjects participated in the study. Regions of interest were selected on the basis of published voxelwise findings and placed within major fiber tracts using Talairach's stereotaxic coordinates.

RESULTS

Fractional anisotropy reductions in schizophrenia patients were confirmed in the left cingulum, anterior thalamic radiation, fronto-occipital and inferior longitudinal fasciculi, as well as bilaterally in the corpus callosum, anterior and posterior limbs of internal capsule, superior longitudinal fasciculus, optic radiation, and frontotemporal extrafascicular white matter. Anisotropy reductions were more extensive in patients with poor outcomes ("Kraepelinian"), particularly in the posterior corpus callosum, fronto-occipital fasciculus, left optic radiation and frontotemporal white matter. Lower anisotropy in the right hemisphere tracts was associated with more prominent positive symptomatology, whereas negative symptoms were inversely associated with anisotropy values in both hemispheres.

CONCLUSIONS

These results support a global neural disconnectivity in schizophrenia patients, which is more severe in those with poor clinical outcomes.

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.

Allelic variation in RGS4 impacts functional and structural connectivity in the human brain

Regulator of G-protein signaling 4 (RGS4) modulates postsynaptic signal transduction by affecting the kinetics of G alpha-GTP binding. Linkage, association, and postmortem studies have implicated the gene encoding RGS4 (RGS4) as a schizophrenia susceptibility factor. Using a multimodal neuroimaging approach, we demonstrate that genetic variation in RGS4 is associated with functional activation and connectivity during working memory in the absence of overt behavioral differences, with regional gray and white matter volume and with gray matter structural connectivity in healthy human subjects. Specifically, variation at one RGS4 single nucleotide polymorphism that has been associated previously with psychosis (rs951436) impacts frontoparietal and frontotemporal blood oxygenation level-dependent response and network coupling during working memory and results in regionally specific reductions in gray and white matter structural volume in individuals carrying the A allele. These findings suggest mechanisms in brain for the association of RGS4 with risk for psychiatric illness.

Cerebral grey, white matter and csf in never-medicated, first-episode schizophrenia

We report the first voxel-based morphometric (VBM) study to examine cerebral grey and white matter and cerebrospinal fluid (CSF) using computational morphometry in never-medicated, first-episode psychosis (FEP). Region-of-interest (ROI) analysis was also performed blind to group membership. 26 never-medicated individuals with FEP (23 with DSM-IV schizophrenia) and 38 healthy controls had MRI brain scans. Groups were balanced for age, sex, handedness, ethnicity, paternal socio-economic status, and height. Healthy controls were recruited from the local community by advertisement. Grey matter, white matter, and CSF: global brain volume ratios were significantly smaller in patients. Patients had significantly less grey matter volume in L and R caudate nuclei, cingulate gyri, parahippocampal gyri, superior temporal gyri, cerebellum and R thalamus, prefrontal cortex. They also had significantly less white matter volume in the R anterior limb of the internal capsule fronto-occipital fasciculus and L and R fornices, and significantly greater CSF volume especially in the R lateral ventricle. Excluding the 3 subjects with brief psychotic disorder did not alter our results. Our data suggest that fronto-temporal and subcortical-limbic circuits are morphologically abnormal in never-medicated, schizophrenia. ROI analysis comparing the schizophrenia group (n=23) with the healthy controls (n=38) confirmed caudate volumes were significantly smaller bilaterally by 11%, and lateral ventricular volume was significantly larger on the right by 26% in the patients. Caudate nuclei and lateral ventricular volume measurements were uncorrelated (Pearson correlation coefficient 0.30, p=0.10), ruling out the possibility of segmentation artefact. Ratio of lateral ventricle to caudate volume was bilaterally significantly increased (p<0.005, 2-tailed), which could represent an early biomarker in first-episode, never-medicated schizophrenia.

Serotonin 1A receptor availability in patients with schizophrenia and schizo-affective disorder: a positron emission tomography imaging study with [11C]WAY 100635

BACKGROUND

Postmortem and positron emission tomography (PET) studies have reported several alterations in serotonin 1A receptor (5-HT(1A)) binding parameters in patients with schizophrenia. This study examines 5-HT(1A) availability in vivo in individuals with schizophrenia and schizo-affective disorder.

MATERIALS AND METHODS

Twenty-two medication-free individuals with schizophrenia or schizo-affective disorder and 18 healthy subjects underwent PET scans with [(11)C]WAY 100635. Regional distribution volumes (V(T), in milliliters per gram) were derived using a two-tissue compartment kinetic model. Outcome measures for 5-HT(1A) availability included binding potential (BP) and the specific to nonspecific equilibrium partition coefficient (V(3)''). Eleven brain regions with high density of 5-HT(1A) were included in the analysis.

RESULTS

No significant differences were observed in regional BP or V(3)'' between patients and controls. No significant relationships were observed between regional 5-HT(1A) availability and symptom severity.

CONCLUSION

The postmortem literature reports increased 5-HT(1A) binding in the prefrontal cortex in schizophrenia. This study did not detect differences in 5-HT(1A) binding. Whereas in two recently published PET studies, one reports increased binding in the temporal lobe while the other reports decreased binding in the amygdala. These inconsistencies suggest that the alterations demonstrated in postmortem studies cannot be reliably detected at the resolution achieved with PET. This raises the question as to whether major changes in the level of expression of the 5-HT(1A) receptor play a role in the pathophysiology of schizophrenia.

The influence of sulcal variability on morphometry of the human anterior cingulate and paracingulate cortex

Human anterior cingulate (ACC) and paracingulate (PaC) cortices play an important role in cognitive and affective regulation and have been implicated in numerous psychiatric and neurological conditions. The region they comprise displays marked inter-individual variability in sulcal and gyral architecture, and although recent evidence suggests that this variability has functional significance, it is often ignored in automated and region-of-interest (ROI) morphometric investigations. This has lead to confounded interpretation of results and inconsistent findings across a number of studies and in a variety of clinical populations. In this paper, we present a reliable method for parcellating the dorsal, ventral, and subcallosal ACC and PaC that accounts for individual variation in the local cortical folding pattern. We also investigated the effect of one well characterized morphological variation, the incidence of the paracingulate sulcus (PCS), on regional volumes in 24 (12 male, 12 female) healthy participants. The presence of a PCS was shown to affect both ACC and PaC volumes, such that it was associated with an 88% increase in paracingulate cortex and a concomitant 39% decrease in cingulate cortex. These findings illustrate the potential confounds inherent in morphometric approaches that ignore or attempt to minimize inter-individual variations in sulcal and gyral anatomy and underscore the need to consider this variability when attempting to understand disease processes or characterize brain structure-function relationships.

Multivariate voxel-based morphometry successfully differentiates schizophrenia patients from healthy controls

Currently available laboratory procedures might provide additional information to psychiatric diagnostic systems for more valid classifications of mental disorders. To identify the correlative pattern of gray matter distribution that best discriminates schizophrenia patients from healthy subjects, we applied discriminant function analysis techniques using the multivariate linear model and the voxel-based morphometry. The first analysis was conducted to obtain a statistical model that classified 30 male healthy subjects and 30 male schizophrenia patients diagnosed according to current operational criteria. The second analysis was performed to prospectively validate the statistical model by successfully classifying a new cohort that consisted of 16 male healthy subjects and 16 male schizophrenia patients. Inferences about the structural relevance of the gray matter distribution could be made if the individual profile of pattern expression could be linked to the specific diagnosis of each subject. The result was that 90% of the subjects were correctly classified by the eigenimage, and the Jackknife approach revealed well above chance accuracy. The pattern of the eigenimage was characterized by positive loadings indicating gray matter decline in the patients in the lateral and medial prefrontal regions, insula, lateral temporal regions, medial temporal structures, and thalamus as well as the negative loadings reflecting gray matter increase in the patients in the putamen and cerebellum. When the eigenimage derived from the original cohort was applied to classify data from the second cohort, it correctly assigned more than 80% of the healthy subjects and schizophrenia patients. These findings suggest that the characteristic distribution of gray matter changes may be of diagnostic value for schizophrenia.

Structural brain abnormalities in early onset first-episode psychosis

BACKGROUND

Brain morphometry in children and adolescents with first-episode psychosis offer a unique opportunity for pathogenetic investigations.

METHODS

We compared high-resolution 3D T1-weighted magnetic resonance images of the brain in 29 patients (schizophrenia, schizotypal disorder, delusional disorder or other non-organic psychosis), aged 10-18 to those of 29 matched controls, using optimized voxel-based morphometry.

RESULTS

Psychotic patients had frontal white matter abnormalities, but expected (regional) gray matter reductions were not observed. Post hoc analyses revealed that schizophrenia patients (n = 15) had significantly larger lateral ventricles as compared to controls. Duration and dose of antipsychotics correlated negatively with global gray matter volume in minimally medicated patients (n = 18).

CONCLUSION

Findings of white matter changes and enlarged lateral ventricles already at illness onset in young schizophrenia spectrum patients, suggests aberrant neurodevelopmental processes in the pathogenesis of these disorders. Gray matter volume changes, however, appear not to be a key feature in early onset first-episode psychosis.

Aging in the CNS: comparison of gray/white matter volume and diffusion tensor data

This study investigated the global and regional effects of aging on brain volume, mean diffusivity (MD), and fractional anisotropy (FA) in 73 normal female subjects using voxel-based analysis. On a global scale, gray matter volume and FA were negatively correlated, whereas MD was positively correlated with age. Voxel-wise analyses showed brain volume and FA were negatively correlated predominantly in anterior structures, whereas MD was positively correlated in the cortical gray matter and periventricular white matter. Volume preservation was observed in the cingulate gyrus and subjacent white matter. FA increase was observed in the putamen. Voxel-based direct comparisons of volume and diffusion properties showed FA was more strongly negatively correlated in the fronto-temporal white matter, compared with volume and MD. Stronger positive correlation of MD was observed in the thalamus, caudate nucleus, and midbrain and stronger negative correlation of brain volume was observed in the frontal lobe and basal ganglia, compared with the other. These results indicate that diffusion properties and brain volume are complementary markers to the effects of aging.

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

Although several brain morphologic studies have suggested abnormalities in the temporal regions to be a common indicator of vulnerability for the schizophrenia spectrum, less attention has been paid to temporal lobe structures other than the superior temporal gyrus or the medial temporal region. In this study, we investigated the volume of gray matter in the fusiform gyrus, the parahippocampal gyrus, the middle temporal gyrus, and the inferior temporal gyrus using magnetic resonance imaging in 39 schizotypal disorder patients, 65 schizophrenia patients, and 72 age and gender matched healthy control subjects. The anterior fusiform gyrus was significantly smaller in the schizophrenia patients than the control subjects but not in the schizotypal disorder patients, while the volume reduction of the posterior fusiform gyrus was common to both disorders. Volumes for the middle and inferior temporal gyri or the parahippocampal gyrus did not differ between groups. These findings suggest that abnormalities in the posterior region of the fusiform gyrus are, as have been suggested for the superior temporal gyrus or the amygdala/hippocampus, prominent among the temporal lobe structures as a common morphologic substrate for the schizophrenia spectrum, whereas more widespread alterations involving the anterior region might be associated with the development of full-blown schizophrenia.

White matter fractional anisotropy and outcome in schizophrenia

OBJECTIVE

Disparate white matter fractional anisotropy (FA) findings have been reported in patients with schizophrenia in recent years. This may in part reflect heterogeneity of subjects in the studies, including differences in outcome and severity of the illness. We examined whether there is a relationship between white matter FA and outcome in patients with schizophrenia.

METHOD

Diffusion-tensor images were obtained in 41 normal subjects and 104 patients with schizophrenia, divided into good-outcome (n=51) and poor-outcome (Kraepelinian; n=53) subtypes based on their ability for self-care. White matter FA and its relationship to regional tissue volumes were evaluated across 40 individual Brodmann's areas using a semi-automated parcellation technique.

RESULTS

Overall white matter FA was lower in schizophrenia patients than normal subjects, with regional reductions in widespread temporoparietal and selected prefrontal white matter regions. In schizophrenia patients, lower regional white matter FA was associated with lower regional gray matter volumes. In comparison to normal subjects, overall white matter FA was reduced in patients with poor outcomes in both hemispheres, but to a lesser extent and only in the right hemisphere in good-outcome patients. Lower regional FA was associated with larger regional white matter volumes in good-outcome group.

CONCLUSIONS

Global FA reductions implicate white matter as tissue type in the pathophysiology of schizophrenia. In contrast to poor outcome, good outcome in schizophrenia patients may be associated with less extensive FA reductions, higher FA in regional frontal and cingulate white matter, and correlated increases in regional white matter volumes, particularly in the left hemisphere.

Morphometric and psychometric comparisons between non-substance-abusing patients with posttraumatic stress disorder and normal controls

BACKGROUND

Hippocampal decrease in size in response to posttraumatic stress disorder (PTSD) is still a subject of controversy. The aims of this study were to: (1) confirm previous hippocampus findings in PTSD patients compared to controls, using ethnically similar study groups where alcohol and drug abuse were non-existent; (2) test influence of disease duration as well as depression scores on possible morphological changes; (3) test whether the voxel-based morphometry (VBM) data confirm the group differences seen in the region of interest (ROI) analysis, and (4) test the associations between the cognitive test scores and the morphological changes.

METHODS

VBM and ROI-based analysis were applied in 23 patients and 17 healthy controls. Culture-neutral cognitive tests were used.

RESULTS

The ROI-based method showed significantly decreased gray matter volumes for global hippocampal volume, as in a separate analysis of left and right sides in the PTSD group. Total volume of the hippocampus was significantly decreased on the left side, as in the global assessment. A multiple regression VBM model showed significant voxel clusters for group affiliation in the right hippocampus, modelling lowering of gray matter associated with the PTSD group. Disease duration was shown to be negatively correlated to bilateral hippocampal volume and high depression score to bilateral gray matter parahippocampal volume. No significant correlations were found between hippocampal or parahippocampal volumes and cognitive functions.

CONCLUSION

The present and previous studies showed that morphologic differences do not appear to be due to drug or alcohol abuse. The VBM data partially confirm the group differences seen in the ROI-based method in the medial temporal lobe. The fact that the significantly lower score on the short-term memory test in the PTSD group is not correlated to hippocampal volume may suggest a more general basis for such memory impairment.

Voxel-based diffusion tensor analysis reveals aberrant anterior cingulum integrity in posttraumatic stress disorder due to terrorism

Recent functional neuroimaging work has suggested that interregional functional connectivity between the anterior cingulate cortex (ACC), other limbic, and prefrontal regions may be involved in the pathophysiology of posttraumatic stress disorder (PTSD). However, less attention has been paid to the white matter network. Voxel-based analysis enables an exploration of morphological or functional changes throughout the entire brain. Here we undertook the first application of this technology to diffusion tensor data in patients with PTSD. Participants were 9 victims of the Tokyo subway sarin attack with PTSD and 16 matched victims of the same traumatic event without PTSD. The voxel-based analysis showed a significant fractional anisotropy increase in the left anterior cingulum, subjacent to the left ACC gray matter where we previously found a volume decrement, in PTSD subjects. Moreover, the severity was positively, but not significantly associated with the fractional anisotropy of the left anterior cingulum in the victims with PTSD, using the region of interest defined in the native space with the inverse normalization technique. The present study demonstrated further evidence of abnormalities of both the ACC, a structure that is pivotally involved in attention, emotional regulation, and fear conditioning, and of subjacent white matter in the pathology of PTSD.

Method for multimodal analysis of independent source differences in schizophrenia: combining gray matter structural and auditory oddball functional data

The acquisition of both structural MRI (sMRI) and functional MRI (fMRI) data for a given study is a very common practice. However, these data are typically examined in separate analyses, rather than in a combined model. We propose a novel methodology to perform independent component analysis across image modalities, specifically, gray matter images and fMRI activation images as well as a joint histogram visualization technique. Joint independent component analysis (jICA) is used to decompose a matrix with a given row consisting of an fMRI activation image resulting from auditory oddball target stimuli and an sMRI gray matter segmentation image, collected from the same individual. We analyzed data collected on a group of schizophrenia patients and healthy controls using the jICA approach. Spatially independent joint-components are estimated and resulting components were further analyzed only if they showed a significant difference between patients and controls. The main finding was that group differences in bilateral parietal and frontal as well as posterior temporal regions in gray matter were associated with bilateral temporal regions activated by the auditory oddball target stimuli. A finding of less patient gray matter and less hemodynamic activity for target detection in these bilateral anterior temporal lobe regions was consistent with previous work. An unexpected corollary to this finding was that, in the regions showing the largest group differences, gray matter concentrations were larger in patients vs. controls, suggesting that more gray matter may be related to less functional connectivity in the auditory oddball fMRI task.

Effects of atypical and typical neuroleptics on anterior cingulate volume in schizophrenia

We have previously found typical neuroleptic exposure to be correlated with an increase in anterior cingulate volume over time in patients with schizophrenia. However, the effect of atypical neuroleptics on anterior cingulate volume and the clinical significance of these changes are not known. To determine if atypicals differ from typicals in their effect on anterior cingulate volume change over time and to assess the clinical significance of such changes, subjects with schizophrenia were compared to normal controls over time. Anterior cingulate volume was delineated with manual traces on magnetic resonance images of the brain in 31 neuroleptic-naïve subjects and 18 normal controls at admission and 2-3 years later. Neuroleptic exposure for each subject was calculated using a dose-year formula. Increased typical neuroleptics exposure over time was correlated to increased anterior cingulate volume over time (r = 0.92, p < 0.001), while increased atypical neuroleptics exposure was correlated to decreased anterior cingulate volume (r = -0.57, p < 0.006). Increased anterior cingulate volume was correlated to greater psychotic symptom improvement (r = 0.78, p < 0.010). Anterior cingulate volume changes over time are correlated differently with atypical versus typical neuroleptic exposure over time. The increase in anterior cingulate volume with typicals is correlated to improved psychotic symptoms over time.

Prefrontal abnormalities in patients with simple schizophrenia: structural and functional brain-imaging studies in five cases

Simple schizophrenia is an uncommon disorder with unknown pathophysiology, and its position in the current diagnostic system is ambiguous. Brain-imaging studies may help to elucidate its pathophysiology. Five patients fulfilling both ICD-10 criteria for simple schizophrenia and DSM-IV criteria for simple deteriorative disorder underwent computed tomography, magnetic resonance imaging, and single photon emission computed tomography. These scans were assessed individually by visual inspection as well as automatically by comparison with scans in normal controls or other schizophrenia subtype patients using voxel-based image analyses. Three of the five simple schizophrenia patients had findings of atrophy and reduced cerebral perfusion in the frontal areas. Voxel-based analyses also showed prefrontal grey matter deficits and hypoperfusion in simple schizophrenia patients compared with the controls. Although this study is limited by the small number of patients with simple schizophrenia, the results suggest that simple schizophrenia, or at least this subpopulation, may have rather homogeneous morphological and functional deficits in the prefrontal cortex. It is also suggested that simple schizophrenia may occupy an extreme position of the schizophrenic continuum where the prefrontal deficits and negative symptoms are most purely manifested.

Empirical comparison of maximal voxel and non-isotropic adjusted cluster extent results in a voxel-based morphometry study of comorbid learning disability with schizophrenia

We present an empirical comparison of cluster extent and maximal voxel results in a voxel-based morphometry (VBM) study of brain structure. The cluster extents are adjusted for underlying deviation from uniform smoothness. We implement this comparison on a four-group cohort that has previously shown evidence of a neuro-developmental component in schizophrenia (Moorhead, T.W.J., Job, D.E., Whalley, H.C., Sanderson, T.L., Johnstone, E.C. and Lawrie, S.M. 2004. Voxel-based morphometry of comorbid schizophrenia and learning disability: analyses in normalized and native spaces using parametric and nonparametric statistical methods. NeuroImage 22: 188-202.). We find that adjusted cluster extent results provide information on the nature of deficits that occur in the schizophrenia affected groups, and these important structural differences are not all shown in maximal voxel results. The maximal voxel and cluster extent results are corrected for multiple comparisons using Random Fields (RF) methods. In order to apply the cluster extent measures, we propose a post-hoc method for determining the primary threshold in the analysis. Unadjusted cluster extent results are reported, for these, no allowance is made for non-isotropic smoothness, and comparison with the adjusted extent results shows that the unadjusted results can be either conservative or anti-conservative depending upon the underlying tissue distributions.

The relationship of structural alterations to cognitive deficits in schizophrenia: a voxel-based morphometry study

BACKGROUND

Region of interest studies have identified a number of structure-cognition associations in schizophrenia and revealed alterations in structure-cognition relationship in this population.

METHODS

We examined the relationship of structural brain alterations, identified using voxel-based morphometry, to cognitive deficits in 45 schizophrenia patients relative to 43 healthy control subjects and tested the hypothesis that structure-cognition relationship is altered in schizophrenia.

RESULTS

Patients had smaller total brain, gray matter, and white matter volumes. Regional alterations were left-hemisphere specific, including: gray matter reduction of inferior frontal, lingual, and anterior superior temporal gyri; white matter reduction of posterior and occipital lobes; and gray matter increase of the putamen and the precuneus. Smaller whole brain and gray matter volumes were associated with lower premorbid intelligence quotient (IQ) and poorer performance on IQ-dependent cognitive measures in patients and to a similar extent in control subjects. Larger precuneus was associated with better immediate verbal memory in patients, whereas verbal and nonverbal memory were positively associated with inferior frontal gyrus volume in control subjects. Smaller occipital white matter volume was associated with slower information processing speed in patients but not in control subjects.

CONCLUSIONS

Regional volume alterations are associated with specific cognitive deficits in schizophrenia. Some structure-cognition relationships differentiate this population from healthy control subjects.

White matter density in patients with schizophrenia, bipolar disorder and their unaffected relatives

BACKGROUND

This study sought to assess white matter density in patients and relatives with histories of bipolar disorder and/or schizophrenia.

METHODS

Subjects included those with schizophrenia from families affected by schizophrenia alone, those with bipolar disorder from families affected by bipolar disorder alone and those with bipolar disorder from families affected by both bipolar disorder and schizophrenia. Unaffected relatives of the three patient groups were also recruited. Subjects underwent an MRI brain scan which was analyzed using a white-matter optimized technique.

RESULTS

Subjects with schizophrenia and bipolar disorder showed reduced white matter density in the anterior limb of the internal capsule which was not found in unaffected relatives. Reductions were found in frontal subgyral white matter density in affected subjects with a family history of schizophrenia only.

CONCLUSIONS

Abnormal anterior internal capsule white matter may provide a structural substrate for both disorders.

Volumetric analysis of sulci/gyri-defined in vivo frontal lobe regions in schizophrenia: Precentral gyrus, cingulate gyrus, and prefrontal region

Methodological limitations in most previous magnetic resonance imaging (MRI)-based volumetric studies might have contributed to the inconsistent results regarding the frontal lobe regions of schizophrenia. Thus, applying the largest sample to date among those that have fully taken account of the intrinsic anatomical landmarks, this study aimed at clarifying the volumetric alterations of the frontal lobe and its subregions in schizophrenia. Participants comprised 59 patients with schizophrenia and 58 healthy controls. Measurements were performed on consecutive 1-mm-thick coronal slices reformatted from three-dimensional 1.5-T MR images. The whole frontal lobe was demarcated and then subdivided into the precentral gyrus (PCG), anterior cingulate, and posterior cingulate, and the remainder temporarily as the prefrontal region. Patients with schizophrenia had significant cortical volume reductions in the bilateral whole frontal lobe, prefrontal region, PCG, posterior cingulate, and right anterior cingulate. This study has confirmed that patients with schizophrenia do have cortical volume reductions in the whole frontal lobe and its subregions. Volume reduction in the PCG suggests that the primary motor cortex might contribute to the mechanisms of schizophrenia, considering its important role in the processing of multiple motor-related cognitive functioning suggested by the recent literature.

Cortical thinning in cingulate and occipital cortices in first episode schizophrenia

BACKGROUND

Postmortem studies examining discrete regions show reduced cortical thickness in schizophrenia. Computational image analysis methods allow spatially detailed cortical thickness measurements across the entire cortex in 3D, but have not addressed thickness changes in cingulate or other cortices bordering the medial walls of the cerebral hemispheres in first episode schizophrenia.

METHODS

Magnetic resonance images and cortical pattern matching methods were used to compare gray matter thickness, measured at sub-voxel resolution at thousands of spatially equivalent locations on the medial hemispheric surfaces, between 72 (51m/21f) first episode schizophrenia patients and 78 (37m/41f) healthy controls similar in age. Group differences were mapped in 3D, and their overall significance was confirmed by permutation testing.

RESULTS

Patients with little or no prior antipsychotic medication treatment showed significant cortical thinning within cingulate, occipital and frontopolar cortices with no significant increases in any cortical location. Regional sex differences were observed with pronounced thinning in the left paracentral lobule and right posterior cingulate in male and female patients respectively compared to same sex controls.

CONCLUSIONS

Cortical thinning may correspond to cytoarchitectural and neurochemical abnormalities observed in similar anatomic locations and may underlie systems-wise disturbances that include heteromodal association cortices, where cortical thinning has been previously observed in first episode schizophrenia.

Differential contributions of prefrontal and temporolimbic pathology to mechanisms of psychosis

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