Estimating multimodal brain variability in schizophrenia spectrum disorders: A worldwide ENIGMA study

Objective

Schizophrenia is a multifaceted disorder associated with structural brain heterogeneity. Despite its relevance for identifying illness subtypes and informative biomarkers, structural brain heterogeneity in schizophrenia remains incompletely understood. Therefore, the objective of this study was to provide a comprehensive insight into the structural brain heterogeneity associated with schizophrenia.

Methods

This meta- and mega-analysis investigated the variability of multimodal structural brain measures of white and gray matter in individuals with schizophrenia versus healthy controls. Using the ENIGMA dataset of MRI-based brain measures from 22 international sites with up to 6139 individuals for a given brain measure, we examined variability in cortical thickness, surface area, folding index, subcortical volume and fractional anisotropy.

Results

We found that individuals with schizophrenia are distinguished by higher heterogeneity in the frontotemporal network with regard to multimodal structural measures. Moreover, individuals with schizophrenia showed higher homogeneity of the folding index, especially in the left parahippocampal region.

Conclusions

Higher multimodal heterogeneity in frontotemporal regions potentially implies different subtypes of schizophrenia that converge on impaired frontotemporal interaction as a core feature of the disorder. Conversely, more homogeneous folding patterns in the left parahippocampal region might signify a consistent characteristic of schizophrenia shared across subtypes. These findings underscore the importance of structural brain variability in advancing our neurobiological understanding of schizophrenia, and aid in identifying illness subtypes as well as informative biomarkers.

Choroid Plexus Enlargement and Allostatic Load in Schizophrenia

Although schizophrenia is a brain disorder, increasing evidence suggests that there may be body-wide involvement in this illness. However, direct evidence of brain structures involved in the presumed peripheral-central interaction in schizophrenia is still unclear. Seventy-nine previously treatment-naïve first-episode schizophrenia patients who were within 2-week antipsychotics initial stabilization, and 41 age- and sex-matched healthy controls were enrolled in the study. Group differences in subcortical brain regional structures measured by MRI and the subclinical cardiovascular, metabolic, immune, and neuroendocrine biomarkers as indexed by allostatic load, and their associations were explored. Compared with controls, patients with schizophrenia had significantly higher allostatic load (P = .001). Lateral ventricle (P < .001), choroid plexus (P < .001), and thalamus volumes (P < .001) were significantly larger, whereas amygdala volume (P = .001) was significantly smaller in patients. The choroid plexus alone was significantly correlated with higher allostatic load after age, sex, education level, and the total intracranial volume were taken into account (t = 3.60, P < .001). Allostatic load was also significantly correlated with PANSS positive (r = 0.28, P = .016) and negative (r = -0.31, P = .008) symptoms, but in opposite directions. The peripheral multisystemic and central nervous system abnormalities in schizophrenia may interact through the choroid plexus during the early stage of the illness. The choroid plexus might provide a sensitive structural biomarker to study the treatment and prevention of brain-periphery interaction abnormalities in schizophrenia.

Brain Abnormalities in Different Phases of Working Memory in Schizophrenia: An Integrative Multi-Modal MRI Study

The current study aimed to examine both gray matter and functional activity changes in schizophrenia by combing both structural and task-related functional magnetic resonance imaging (fMRI). Nineteen patients with schizophrenia and 17 controls were recruited. The fMRI scan was performed while performing a working memory (WM) task. In terms of task performance, accuracy did not differ between groups, but there were significant differences in reaction time. Compared with controls, patients exhibited decreased functional activation in prefrontal areas, insula, lingual gyrus, and superior temporal gyrus during different phases of WM. The subcallosal cortex showed increased activation. Intriguingly, a structural-functional correlation was found in the left dorsolateral prefrontal cortex, anterior cingulate cortex, and subcallosal cortex in patients when performing high-load WM task. This study demonstrated both impaired gray matter volume and functional activation during WM in schizophrenia, suggesting structural and functional impairments. The structural-functional correlation in schizophrenia suggested that structural damage in schizophrenia might induce a decreased ability to modulate functional response in accordance with increasing task difficulty.

Extensive white matter abnormalities and clinical symptoms in drug-naive patients with first-episode schizophrenia: a voxel-based diffusion tensor imaging study

BACKGROUND

Increasing evidence shows that disruption of connectivity has been implicated as a central abnormality in schizophrenia, and the alterations in white matter may be the core basis for this disconnection. Diffusion tensor imaging (DTI) has shown white matter abnormalities in first-episode schizophrenia. However, few studies have examined the correlation between clinical symptoms and white matter abnormalities in drug-naive patients with first-episode schizophrenia.

METHOD

The white matter fractional anisotropy (FA) values of the whole-brain were determined by using voxel-based DTI in 39 drug-naive patients with first-episode schizophrenia (diagnosed according to DSM-IV) and 30 healthy controls matched for age and gender. The psychopathology of schizophrenia was assessed with the Positive and Negative Syndrome Scale (PANSS). The study was conducted from April 2009 to March 2010.

RESULTS

The patients showed widespread FA reduction in several brain regions, including corpus callosum, brainstem, internal capsule, cingulate, and cerebellum in patients with first-episode schizophrenia when compared to healthy controls (all P values < .01 after adjusting for gender, age, and education). The correlation analysis showed a significant negative correlation between the FA value in the left cerebellum and positive symptoms (r38 = -0.32, P < .05) and a significant positive correlation between the FA values in the corpus callosum and both the PANSS general psychopathology subscore (r38 = 0.39, P < .01) and the PANSS total score (r38 = 0.33, P < .05).

CONCLUSIONS

Our results indicate that widespread disruption of white matter integrity occurs in an early stage of schizophrenic onset, suggesting an important role in pathogenesis and symptomatology of schizophrenia.

Changes of gray matter volume and amplitude of low-frequency oscillations in amnestic MCI: An integrative multi-modal MRI study

BACKGROUND

Numerous studies have reported that the amnestic-type mild cognitive impairment (aMCI) patients have impaired brain structural integrity and functional alterations separately.

PURPOSE

To investigate the changes of gray matter and amplitude of low-frequency oscillations in patients with aMCI by combining structural and functional magnetic resonance imaging (fMRI).

MATERIAL AND METHODS

Thirty-four patients with aMCI and 34 controls were recruited. We adopted optimized voxel-based morphometry to detect regions with gray matter volume (GMV) loss induced by aMCI. Then regional differences in amplitude of slow-4 band (0.027-0.073 Hz) oscillations among these regions between patients and healthy controls were examined. Both slow-4 amplitude of low-frequency fluctuations (ALFF) and slow-4 fractional ALFF (fALFF; the relative amplitude that resides in the low frequencies) were employed.

RESULTS

Patients with aMCI demonstrated significant GMV loss in the ventral medial prefrontal cortex (vMPFC), posterior cingulate cortex (PCC), bilateral hippocampus, right superior parietal gyrus, left insula and left middle temporal gyrus (P < 0.01). The patients exhibited significant decreases of slow-4 ALFF in the left hippocampus (P = 0.05) and PCC (P = 0.02), while the decreased slow-4 fALFF was detected in PCC (P = 0.01) and increased slow-4 fALFF in vMPFC (P = 0.03). In PCC, aMCI and controls exhibited significant different GMV-fALFF correlation (P < 0.05), with opposite correlation trend.

CONCLUSION

The correlates between anatomical deficits and functional alterations in aMCI suggest that anatomical and functional deficits are linked to each other. The differences of GMV-fALFF correlations demonstrated altered anatomical-functional relationship in aMCI.

Smoking, MATRICS consensus cognitive battery and P50 sensory gating in a Han Chinese population

BACKGROUND

The effects of smoking on cognitive performance have long been studied, with mixed results. P50 sensory gating has been used as endophenotype for studying nicotinic systems genetics, and P50 gating deficits have been reported to be a sensitive biomarker for cognitive impairment in schizophrenia. This study examined the inter-relationship between P50 suppression, cognitive function, and smoking in a healthy Han Chinese population, which has not been reported before.

METHODS

We recruited 82 healthy male subjects, including 48 smokers and 34 non-smokers who were matched for age and education. The authors measured P50 sensory gating and administered the Chinese-language version of the MATRICS consensus cognitive battery (MCCB) and Stroop tests.

RESULTS

The results showed that the smokers scored lower than nonsmokers on the MCCB brief visuospatial memory test (BVMT) index and the STROOP test. Furthermore, the MCCB total score was negatively associated with number of cigarettes smoked per day in the smoker group. However, P50 sensory gating was not associated with either smoking status or any cognitive performance.

CONCLUSIONS

Our results show that smoking is associated with cognitive impairment, but not with P50 sensory gating.

Topological organization of the human brain functional connectome across the lifespan

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We study topological organization changes of functional connectome in ages 7–85.

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The functional connectome exhibits linear decreases of modularity over the lifespan.

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Both rich-club and local organization have inverted-U shaped lifespan trajectories.

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Heterogeneous age effects are mainly localized to hub regions.

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Connectivity reorganization over lifespan is anatomically distance-dependent.

Human brain function undergoes complex transformations across the lifespan. We employed resting-state functional MRI and graph-theory approaches to systematically chart the lifespan trajectory of the topological organization of human whole-brain functional networks in 126 healthy individuals ranging in age from 7 to 85 years. Brain networks were constructed by computing Pearson's correlations in blood-oxygenation-level-dependent temporal fluctuations among 1024 parcellation units followed by graph-based network analyses. We observed that the human brain functional connectome exhibited highly preserved non-random modular and rich club organization over the entire age range studied. Further quantitative analyses revealed linear decreases in modularity and inverted-U shaped trajectories of local efficiency and rich club architecture. Regionally heterogeneous age effects were mainly located in several hubs (e.g., default network, dorsal attention regions). Finally, we observed inverse trajectories of long- and short-distance functional connections, indicating that the reorganization of connectivity concentrates and distributes the brain's functional networks. Our results demonstrate topological changes in the whole-brain functional connectome across nearly the entire human lifespan, providing insights into the neural substrates underlying individual variations in behavior and cognition. These results have important implications for disease connectomics because they provide a baseline for evaluating network impairments in age-related neuropsychiatric disorders.

Can Taichi reshape the brain? A brain morphometry study

Although research has provided abundant evidence for Taichi-induced improvements in psychological and physiological well-being, little is known about possible links to brain structure of Taichi practice. Using high-resolution MRI of 22 Tai Chi Chuan (TCC) practitioners and 18 controls matched for age, sex and education, we set out to examine the underlying anatomical correlates of long-term Taichi practice at two different levels of regional specificity. For this purpose, parcel-wise and vertex-wise analyses were employed to quantify the difference between TCC practitioners and the controls based on cortical surface reconstruction. We also adopted the Attention Network Test (ANT) to explore the effect of TCC on executive control. TCC practitioners, compared with controls, showed significantly thicker cortex in precentral gyrus, insula sulcus and middle frontal sulcus in the right hemisphere and superior temporal gyrus and medial occipito-temporal sulcus and lingual sulcus in the left hemisphere. Moreover, we found that thicker cortex in left medial occipito-temporal sulcus and lingual sulcus was associated with greater intensity of TCC practice. These findings indicate that long-term TCC practice could induce regional structural change and also suggest TCC might share similar patterns of neural correlates with meditation and aerobic exercise.

Ventral medial prefrontal functional connectivity and emotion regulation in chronic schizophrenia: a pilot study

People with schizophrenia exhibit impaired social cognitive functions, particularly emotion regulation. Abnormal activations of the ventral medial prefrontal cortex (vMPFC) during emotional tasks have been demonstrated in schizophrenia, suggesting its important role in emotion processing in patients. We used the resting-state functional connectivity approach, setting a functionally relevant region, the vMPFC, as a seed region to examine the intrinsic functional interactions and communication between the vMPFC and other brain regions in schizophrenic patients. We found hypo-connectivity between the vMPFC and the medial frontal cortex, right middle temporal lobe (MTL), right hippocampus, parahippocampal cortex (PHC) and amygdala. Further, there was a decreased strength of the negative connectivity (or anticorrelation) between the vMPFC and the bilateral dorsal lateral prefrontal cortex (DLPFC) and pre-supplementary motor areas. Among these connectivity alterations, reduced vMPFC-DLPFC connectivity was positively correlated with positive symptoms on the Positive and Negative Syndrome Scale, while vMPFC-right MTL/PHC/amygdala functional connectivity was positively correlated with the performance of emotional regulation in patients. These findings imply that communication and coordination throughout the brain networks are disrupted in schizophrenia. The emotional correlates of vMPFC connectivity suggest a role of the hypo-connectivity between these regions in the neuropathology of abnormal social cognition in chronic schizophrenia.