Automated image analysis of disturbed cytoarchitecture in Brodmann area 10 in schizophrenia: a post-mortem study

Evidence that the frontal pole has a significant role in the pathophysiology of schizophrenia

Different regions of the cortex have been implicated in the pathophysiology of schizophrenia. Recently published data suggested there are many more changes in gene expression in the frontal pole (Brodmann's Area (BA) 10) compared to the dorsolateral prefrontal cortex (BA 9) and the anterior cingulate cortex (BA 33) from patients with schizophrenia. These data argued that the frontal pole is significantly affected by the pathophysiology of schizophrenia. The frontal pole is a region necessary for higher cognitive functions and is highly interconnected with many other brain regions. In this review we summarise the growing body of evidence to support the hypothesis that a dysfunctional frontal pole, due at least in part to its widespread effects on brain function, is making an important contribution to the pathophysiology of schizophrenia. We detail the many structural, cellular and molecular abnormalities in the frontal pole from people with schizophrenia and present findings that argue the symptoms of schizophrenia are closely linked to dysfunction in this critical brain region.

Genetic Polymorphisms of Glutathione-Related Enzymes (GSTM1, GSTT1, and GSTP1) and Schizophrenia Risk: A Meta-Analysis

The association between polymorphisms of glutathione-related enzyme (GST) genes and the risk of schizophrenia has been investigated in many published studies. However, their results were inconclusive. Therefore, we performed a meta-analysis to explore the association between the GSTM1, GSTT1, and GSTP1 polymorphisms and the risk of schizophrenia. Twelve case-control studies were included in this meta-analysis. The odds ratio (OR) and 95% confidence interval (95% CI) were used to investigate the strength of the association. Our meta-analysis results revealed that GSTM1, GSTT1, and GSTP1 polymorphisms were not related to risk of schizophrenia (p > 0.05 in each model). Further analyses based on ethnicity, GSTM polymorphism showed weak association with schizophrenia in East Asian population (OR = 1.314, 95% CI = 1.025–1.684, p = 0.031). In conclusion, our meta-analysis indicated the GSTM1 polymorphism may be the only genetic risk factor for schizophrenia in East Asian population. However, more meta-analysis with a larger sample size were needed to provide more precise evidence.

Association of poor insight in schizophrenia with structure and function of cortical midline structures and frontopolar cortex

BACKGROUND

Poor insight is a central characteristic of psychosis and schizophrenia. Accumulating evidence indicates that cortical midline structures (CMS) and frontopolar cortex (FPC), both of which are associated with insight-related processing in healthy subjects, are among the most affected brain structures in schizophrenia. However, the hypothesis that direct associations between function of these brain regions and poor insight in schizophrenia exist has not been tested previously.

METHODS

We studied 21 patients with schizophrenia and 17 healthy control subjects with structural and functional magnetic resonance imaging during a clinical insight task and a comparable control task. We assessed the level of insight, depression, positive and negative symptoms, and neurocognitive function, then adjusted correlation between insight and insight-task-related brain activation for potential confounders. Voxel-based morphometry was used to compare brain volumes between groups.

RESULTS

Insight correlated strongly with the activation of the CMS and the FPC during the clinical insight tasks, independently of potential confounders. The CMS activation was stronger during the insight task than during the control task in patients. The functional correlates of insight matched the distribution of cortical volume reduction in the patient group.

CONCLUSIONS

These findings suggest a link between known regional brain abnormalities and the manifestation of poor insight in schizophrenia. The contribution of CMS to insight may be related to self-referential processing and that of FPC to the integration of multiple cognitive processes that are necessary for accurate evaluation of one's mental illness.

Schizophrenia: from the brain to peripheral markers. A consensus paper of the WFSBP task force on biological markers

Objective. The phenotypic complexity, together with the multifarious nature of the so-called "schizophrenic psychoses", limits our ability to form a simple and logical biologically based hypothesis for the disease group. Biological markers are defined as biochemical, physiological or anatomical traits that are specific to particular conditions. An important aim of biomarker discovery is the detection of disease correlates that can be used as diagnostic tools. Method. A selective review of the WFSBP Task Force on Biological Markers in schizophrenia is provided from the central nervous system to phenotypes, functional brain systems, chromosomal loci with potential genetic markers to the peripheral systems. Results. A number of biological measures have been proposed to be correlated with schizophrenia. At present, not a single biological trait in schizophrenia is available which achieves sufficient specificity, selectivity and is based on causal pathology and predictive validity to be recommended as diagnostic marker. Conclusions. With the emergence of new technologies and rigorous phenotypic subclassification the identification of genetic bases and assessment of dynamic disease related alterations will hopefully come to a new stage in the complex field of psychiatric research.

Automated gray level index measurements reveal only minor cytoarchitectonic changes of Brodmann area 9 in schizophrenia

Using an automatized gray level index (GLI) method, we recently found cytoarchitectonic abnormalities in schizophrenia in Brodmann area 10 (BA10) [Vogeley, K., Tepest, R., Schneider-Axmann, T., Hutte, H., Zilles, K., Honer, W.G., Falkai, P., 2003. Automated image analysis of disturbed cytoarchitecture in Brodmann area 10 in schizophrenia, Schizophrenia Research 62, 133-140]. As another potential key region involved in the pathophysiology of schizophrenia, we have now investigated BA9 in the same sample consisting of 20 schizophrenic cases and 20 controls. The GLI value represents the area-percentage covered by perikarya in measuring fields of microscopic images. BA9 was analyzed with respect to the factors diagnosis and gender for six different compartments approximately corresponding to the neocortical layers. The main result in BA9 was a significant interaction of diagnosis and gender for GLI in layers IV and V on the left side. Subsequent analyses separately performed concerning gender revealed a significant GLI increase in layer V on the left side in male patients compared with controls. However, after an adjustment of error probabilities for multiple testing, differences did not reach significance. No GLI difference was observed in the sample between diagnostic groups for females and between the diagnostic groups in general. Comparisons with our BA10 results suggest that cytoarchitectural changes relevant to schizophrenia appear different in various Brodmann areas. Since increases in GLI were found only in selected layers (V and VI) of BA9, these findings do not support a generalized neuropil reduction across all cortical layers.

Is brain banking of psychiatric cases valuable for neurobiological research?

It is widely accepted that neurobiological abnormalities underlie the symptoms of psychiatric disorders such as schizophrenia and unipolar or bipolar affective disorders. New molecular methods, computer-assisted quantification techniques and neurobiological investigation methods that can be applied to the human brain are all used in post-mortem investigations of psychiatric disorders. The following article describes modern quantitative methods and recent post-mortem findings in schizophrenia and affective disorders. Using our brain bank as an example, necessary considerations of modern brain banking are addressed such as ethical considerations, clinical work-up, preparation techniques and the organization of a brain bank, the value of modern brain banking for investigations of psychiatric disorders is summarized.

Intact hippocampal gray matter in schizophrenia as revealed by automatized image analysis postmortem

Implicated as a key structure in the pathophysiology of schizophrenia, the hippocampus is at the forefront of neuropathological and neuroimaging research. To elucidate the cellular basis of hippocampal pathology in schizophrenia, we studied the postmortem hippocampal sections of 16 patients suffering from schizophrenia and 16 controls applying the gray-level index (GLI) method. We determined the area-percentage covered by neuronal perikarya in relation to the total area of the pyramidal cell layer in the four subdivisions of the ammon's horn (cornu ammonis, CA1-4) bilaterally. Additionally, we determined the area size of the pyramidal cell layer (CA1-4) and dentate gyrus (DG) granule cell layer. Results showed no significant differences between diagnostic groups with respect to the dependent variables, supporting the view that there is no primary alteration of hippocampal gray matter in schizophrenia.

Review of cognition and brain structure in schizophrenia: profiles, longitudinal course, and effects of treatment

Research on the cognitive and brain structural correlates of schizophrenia has seen tremendous progress over the past decade. It has become increasingly clear that there is no pathognomic neuropsychological or structural neuroanatomic profile in schizophrenia, likely due in part to etiological heterogeneity within the disorder. Nonetheless, several studies have indicated that verbal episodic memory and vigilance deficits are particularly prominent, and are observed even in untreated patients in their first episode of the disorder. The course of schizophrenia appears to be somewhat variable, and factors that contribute to the development of the illness, and in some patients, deterioration of cognitive functioning, have not been elucidated clearly. Neurodevelopmental factors, however, likely play an important role in the diathesis of the disorder, while neuropathological processes contribute to deterioration and progression. At this time, there are relatively few controlled comparisons of the cognitive effects of atypical and conventional antipsychotic medications. Additional studies of the potential effects of antipsychotic medications on structural brain abnormalities are warranted. It is hoped that newer innovative psychopharmacological approaches and neuropsychological remediation programs will, in the not-too-distant future, provide clinicians with a variety of means to improve the cognitive and social functioning of their patients.

Near-infrared spectroscopy analysis of frontal lobe dysfunction in schizophrenia

BACKGROUND

Previous studies have shown that near-infrared spectroscopy (NIRS) has high temporal resolution, requires little restraint, and is suitable for examining the effect of psychological tasks on brain circulation. In the present study, frontal function in schizophrenic patients was analyzed by NIRS during random number generation (RNG), ruler-catching (RC), and sequential finger-to-thumb (SFT) tasks.

METHODS

Two sets of NIRS probes were attached to the foreheads of 13 schizophrenic patients and 10 control subjects approximately at Fp1-F7 and Fp2-F8. Near-infrared spectroscopy was conducted at a sampling rate of 1 Hz, with the pathlength being determined by time-resolved spectroscopy with differential pathlength factor measurements. The absolute changes in oxygenated (oxy-Hb) and deoxygenated (deoxy-Hb) hemoglobin concentrations in response to each task were measured, and total hemoglobin (total-Hb) concentration was calculated as the sum of the two.

RESULTS

During RNG task, total- and oxy-Hb concentrations increased, and deoxy-Hb decreased, but the responses were significantly smaller in schizophrenic patients. During RC task, oxy-Hb in schizophrenic patients tended to decrease, in contrast to the mostly increasing response in control subjects. No group difference was observed during SFT task.

CONCLUSIONS

Task-dependent profile of functional abnormalities was observed in schizophrenic frontal brain metabolism. These results support the usefulness of NIRS data in investigating frontal lobe dysfunction and evaluating psychopathologic condition in schizophrenic patients.

Automated image analysis of disturbed cytoarchitecture in Brodmann area 10 in schizophrenia

To detect cytoarchitectonic abnormalities in the Brodmann area 10 (BA10) of schizophrenic patients, we applied a newly modified variant of the gray-level index (GLI) method as fully automated image analysis method providing cytoarchitectonic profiles of the whole cortex as a scanning tool. Microscopic images of silver-stained sections of 20 schizophrenic brains compared to 20 control brains were automatically scanned and binarized at an adaptive threshold. In 30 measuring fields through the whole cortical depth, the dependent measure of gray-level index (GLI) as the area-percentage covered by perikarya in a measuring field was obtained providing a cytoarchitectonic profile. GLI is an estimate of the volume density of perikarya. A statistical analysis of mean GLI values was performed for six compartments, separately, approximately corresponding to cortical layers. Results revealed significant GLI reductions in schizophrenic brains in all six compartments suggesting either a decreased perikarya fraction or an increased neuropil fraction. The described automated image analysis method providing cytoarchitectonic profiles can be applied as a fast and observer-independent scanning tool to detect cytoarchitectonic abnormalities in multiple brain regions.

Association study between glutathione S-transferase P1 polymorphism and schizophrenia in the Korean population

This study is aimed to test the association between the coding sequence functional polymorphism (Ile105Val) of glutathione S-transferase P gene (GSTP1) and schizophrenia in the Korean population. Two hundred fourteen patients with schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) criteria and 110 healthy controls were enrolled in this study. Patients and controls were biologically unrelated age and sex-matched native Koreans. Genotyping for GSTP1 polymorphism was performed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). Genotype and allele distributions of GSTP1 polymorphism in patients with schizophrenia were not significantly different from those of the controls. Comparisons of clinical variables including Positive and Negative Syndrome Scale (PANSS), change of Brief Psychiatric Rating Scale (BPRS), number of admission, and onset age also were not different according to genotype distribution. The present study suggests that GSTP1 polymorphism may not confer susceptibility to development of schizophrenia in the Korean population.

Hippocampal and prefrontal cortical inputs monosynaptically converge with individual projection neurons of the nucleus accumbens

Afferents to the nucleus accumbens from different sources innervate specific areas of the central "core" and peripheral "shell" and are related to each other, at the light microscopical level, in an intricate overlapping and nonoverlapping way. This lack of homogeneity suggests that this region consists of circuits involving emsembles of neurons modulated by specific sets of convergent afferent inputs and abnormal regulation of such ensembles has been implicated in mental disorders. Early extracellular studies suggested that individual Acb neurons might respond to activation of afferents from more than one excitatory input: More recent studies of hippocampal and amygdalar or prefrontal cortical afferents suggest that hippocampal afferents gate the input from the prefrontal cortex or amygdala. Electrophysiological evidence for convergence of excitatory afferents in the Acb is strong and suggests that these pathways are monosynaptic. Nevertheless, this convergence has proved difficult to demonstrate anatomically as a result of the spatial distribution of the afferent inputs on the dendritic tree of the target neurons. To establish whether individual accumbens neurons receive monosynaptic input from pairs of afferents, one projection was labelled anterogradely with Phaseolus vulgaris leucoagglutinin and the second with biotinylated dextran amine (BDA) with Vector slate grey and 3,3'-diaminobenzidine tetrahydrochloride as the chromagens. Accumbens neurons possibly postsynaptic to these afferents, labelled by an in vivo focal injection of BDA, were examined using correlated light and electron microscopy to establish the proximal-distal distribution of labelled afferent synaptic inputs on their dendritic arbours. Individual cells were shown to receive monosynaptic afferent input from both ventral subiculum and prefrontal cortex, providing an anatomical framework for the hippocampal gating of other limbic inputs to the accumbens.

Mutational analysis of the neuronal cadherin gene CELSR1 and exclusion as a candidate for catatonic schizophrenia in a large family

The cadherin gene CELSR1 is specifically expressed in the brain and located on chromosome 22q13.33, a region that has recently been shown to be involved in the etiopathogenesis of familial catatonic schizophrenia. The gene is a strong positional candidate and was considered for mutational analysis. A total of 17 allelic variants of CELSR1 was found by sequencing all 35 exons, intron-exon junctions, and the putative promoter region by screening two patients from a large family mainly supporting this locus, and three control subjects in a first step. No variant exclusively co-segregates with the disease in the large pedigree, providing evidence that CELSR1 is not causative for the pathogenesis of catatonic schizophrenia in this family.