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Surface based MRI methods are a promising approach for the identification of cerebral shape alterations in schizophrenia . In particular, investigating gyrification might offer important evidence for disturbed neurodevelopmental mechanisms in schizophrenia.
The present study is the first to compare on a vertex - wise basis mean curvature as a sensitive parameter for the identification of local gyrification changes in first episode schizophrenia.
54 patients with first-episode schizophrenia and 54 healthy control subjects underwent high-resolution T1-weighted MRI scans. Surface extraction and mean curvature calculation was performed using the Freesurfer Software package. Statistical cortical maps were created to estimate gyrification differences between groups.
A significantly increased gyrification was detected in patients relative to controls in a large right parahippocampal-lingual cortex area. A further analysis of cortical thickness of this cluster revealed concurrent significant reduced cortical thickness in patients.
This is the first study to reveal an aberrant gyrification of the medial surface in first episode schizophrenia on basis of a vertex - wise analysis of local gyrification changes of the entire cortex. Both affected areas, the parahippocampal and the lingual cortex, are of high pathophysiological relevance for schizophrenia. Thus, our data provided new in vivo evidence for an early maturational deficit of these cortical areas in schizophrenia .
Persistent pondering over negative self-related thoughts is a central feature of depressive psychopathology.
In the present study, we sought to investigate the neural correlates of abnormal negative self-referential processing (SRP) in patients with major depressive disorder (MDD) and its impact on subsequent cognitive control-related neuronal activation.
We hypothesized aberrant activation dynamics during the period of negative and neutral SRP in the rostral anterior cingulate cortex (rACC) and in the amygdala in patients with MDD. We assumed abnormal activation in the fronto-cingulate network during Stroop task execution.
Nineteen depressed patients and 20 healthy controls participated in the study. Using an event-related fMRI design, negative, positive and neutral self-referential statements were displayed for 6.5s and followed by incongruent or congruent Stroop conditions.
In contrast to controls, patients did not exhibit valence-dependent rACC activation differences during SRP. A novel finding was the significant activation of the amygdala and the reward-processing network during presentation of neutral self-referential stimuli relative to baseline and to affective stimuli in patients. The fMRI analysis of the Stroop task revealed a reduced BOLD activation in the right frontoparietal network of patients in the incongruent condition after negative SRP only.
Thus, the inflexible activation in the rACC may correspond to the inability of depressed patients to shift their attention away from negative self-related stimuli. The accompanying negative affect and task-irrelevant emotional processing may compete for neuronal resources with cognitive control processes and lead thereby to deficient cognitive performance associated with decreased frontoparietal activation.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
Alterations in the dopaminergic reward system, predominantly the
striatum, constitute core characteristics of schizophrenia.
Functional connectivity of the dorsal striatum during reward-related
trial-and-error learning was investigated in 17 people with schizophrenia
and 18 healthy volunteers and related to striatal grey matter volume and
We used voxel-based morphometry and psychophysiological interaction to
examine striatal volume and connectivity.
A reduced functional connectivity between left striatum and
temporo-occipital areas, precuneus and insula could be detected in the
schizophrenia group. The positive correlation between grey matter volume
and functional connectivity of the left striatum yielded significant
results in a very similar network. Connectivity of the left striatum was
negatively correlated with negative symptoms.
Present results suggest a disruption in striatal functional connectivity
that is closely linked to grey matter morphometry of the striatum.
Decreased connectivity between the striatum and psychopathologically
relevant networks may explain the emergence of negative symptoms.
Genetic variation in the gene encoding ZNF804A, a risk gene for schizophrenia, has been shown to affect brain functional endophenotypes of the disorder, while studies of white matter structure have been inconclusive.
We analysed effects of ZNF804A single nucleotide polymorphism rs1344706 on grey and white matter using voxel-based morphometry (VBM) in high-resolution T1-weighted magnetic resonance imaging scans of 62 schizophrenia patients and 54 matched healthy controls.
We found a significant (p < 0.05, family-wise error corrected for multiple comparisons) interaction effect of diagnostic group x genotype for local grey matter in the left orbitofrontal and right and left lateral temporal cortices, where patients and controls showed diverging effects of genotype. Analysing the groups separately (at p < 0.001, uncorrected), variation in rs1344706 showed effects on brain structure within the schizophrenia patients in several areas including the left and right inferior temporal, right supramarginal/superior temporal, right and left inferior frontal, left frontopolar, right and left dorsolateral/ventrolateral prefrontal cortices, and the right thalamus, as well as effects within the healthy controls in left lateral temporal, right anterior insula and left orbitofrontal cortical areas. We did not find effects of genotype of regional white matter in either of the two cohorts.
Our findings demonstrate effects of ZNF804A genetic variation on brain structure, with diverging regional effects in schizophrenia patients and healthy controls in frontal and temporal brain areas. These effects, however, might be dependent on the impact of other (genetic or non-genetic) disease factors.
Recent studies have provided strong evidence that variation in the gene neurocan (NCAN, rs1064395) is a common risk factor for bipolar disorder (BD) and schizophrenia. However, the possible relevance of NCAN variation to disease mechanisms in the human brain has not yet been explored. Thus, to identify a putative pathomechanism, we tested whether the risk allele has an influence on cortical thickness and folding in a well-characterized sample of patients with schizophrenia and healthy controls.
Sixty-three patients and 65 controls underwent T1-weighted magnetic resonance imaging (MRI) and were genotyped for the single nucleotide polymorphism (SNP) rs1064395. Folding and thickness were analysed on a node-by-node basis using a surface-based approach (FreeSurfer).
In patients, NCAN risk status (defined by AA and AG carriers) was found to be associated with higher folding in the right lateral occipital region and at a trend level for the left dorsolateral prefrontal cortex. Controls did not show any association (p > 0.05). For cortical thickness, there was no significant effect in either patients or controls.
This study is the first to describe an effect of the NCAN risk variant on brain structure. Our data show that the NCAN risk allele influences cortical folding in the occipital and prefrontal cortex, which may establish disease susceptibility during neurodevelopment. The findings suggest that NCAN is involved in visual processing and top-down cognitive functioning. Both major cognitive processes are known to be disturbed in schizophrenia. Moreover, our study reveals new evidence for a specific genetic influence on local cortical folding in schizophrenia.
Schizophrenia is associated with often widespread changes in white matter
structure. Most studies have investigated changes in fractional
anisotropy, whereas alterations in radial or axial diffusivity have
barely been investigated until now.
To investigate radial diffusivity as a potential marker of dysmyelination
in direct relation to abnormalities in neural activation.
Neural activation in association with decision-making under uncertainty
was investigated in 19 people with schizophrenia and 20 healthy controls
and linked to radial diffusivity as measured by diffusion tensor
Decision-making under uncertainty was associated with a significantly
decreased activation in a frontostriatocingulate network in the
schizophrenia group. Structurally, they exhibited increased radial
diffusivity in temporal white matter that was negatively correlated with
activation in parts of the frontostriatocingulate network.
Present data indicate that altered diffusivity within relevant white
matter networks may be closely linked to abnormal neural activation in
There is increasing evidence that the frequently reported working memory impairments in schizophrenia might be partly due to an alteration in the functional connectivity between task-relevant areas. However, little is known about the functional connectivity patterns in schizophrenia patients during learning processes. In a previous study, Koch et al. [Neuroscience (2007) 146, 1474–1483] have demonstrated stronger exponential activation decreases in schizophrenia patients during overlearning of short-term memory material. The question arises whether these differential temporal patterns of activation in schizophrenia patients and controls are going along with changes in task-related functional connectivity.
Therefore, in the current study, 13 patients with schizophrenia and 13 controls were studied while performing a short-term memory task associated with increasing overlearning of verbal stimulus material. Functional connectivity was investigated by analyses of psychophysiological interactions (PPI).
Results revealed significant task-related modulation of functional connectivity between the left dorsolateral prefrontal cortex (DLPFC) and a network including the right DLPFC, left ventrolateral prefrontal cortex, premotor cortex, right inferior parietal cortex, left and right cerebellum as well as the left occipital lobe in patients during the course of overlearning and practice. No significant PPI results were detectable in controls.
Activation changes with practice were associated with high functional connectivity between task-relevant areas in schizophrenia patients. This could be interpreted as a compensatory resource allocation and network integration in the context of cortical inefficiency and may be a specific neurophysiological signature underlying the pathophysiology of schizophrenia.
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