Mingjun Duan

Functional disconnection between the visual cortex and the sensorimotor cortex suggests a potential mechanism for self-disorder in schizophrenia

UNLABELLED Self-disorder is a hallmark characteristic of schizophrenia. This deficit may stem from an inability to efficiently integrate multisensory bodily signals. Twenty-nine schizophrenia patients and thirty-one healthy controls underwent resting-state fMRI in this study. A data-driven method, functional connectivity density mapping (FCD), was used to investigate cortical functional connectivity changes in the patients. Areas with significantly different FCD were chosen to calculate functional connectivity maps. The schizophrenia patients exhibited increased local FCD in frontal areas while demonstrating decreased local FCD in the primary sensorimotor area and in the occipital lobe. The functional connectivity analysis illustrated decreased functional connectivity between visual areas and the primary sensorimotor area. These findings suggest disturbed integration in perception-motor processing, which may contribute to mapping the neural physiopathology associated with self-disorder in schizophrenia patients. CLINICAL TRIAL REGISTRATION Chinese Clinical Trial Registry. Registration number. ChiCTR-RCS-14004878.

Altered basal ganglia network integration in schizophrenia

The basal ganglia involve in a range of functions that are disturbed in schizophrenia patients. This study decomposed the resting-state data of 28 schizophrenia patients and 31 healthy controls with spatial independent component analysis and identified increased functional integration in the bilateral caudate nucleus in schizophrenia patients. Further, the caudate nucleus in patients showed altered functional connection with the prefrontal area and cerebellum. These results identified the importance of basal ganglia in schizophrenia patients. Clinical Trial Registration: Chinese Clinical Trial Registry. Registration number ChiCTR-RCS-14004878.

Functional abnormalities of the right posterior insula are related to the altered self-experience in schizophrenia

The insula is involved in detecting the salience of internal and external stimuli, and it plays a critical role in psychosis. Previous studies have demonstrated the structural and functional alterations of the insula in schizophrenia. To acquire a full picture of the functional alterations of the insula in schizophrenia, the resting-state fMRI data of 46 patients with schizophrenia and 46 healthy control subjects were collected. We used clustering analysis to divide the insula into three subregions: the dorsal anterior insula (dAI), ventral anterior insula (vAI) and posterior insula (PI). Then, whole-brain functional connectivity analysis was conducted based on these subregions. The results showed that the right dAI and PI in patients exhibited altered functional connections with the primary sensorimotor area. In addition, the right PI of the patients exhibited increased functional correlations with the thalamus. More importantly, the altered functional properties of the right PI were significantly correlated with the severity of the delusion and poor insight in schizophrenia. The results suggested that the right PI might play an important role in self-experience processing in schizophrenia. Accordingly, the right PI should be considered very important in the pathological mechanism of schizophrenia.

Altered Hippocampo-Cerebello-Cortical Circuit in Schizophrenia by a Spatiotemporal Consistency and Causal Connectivity Analysis

In the current study, FOur-dimensional Consistency of local neural Activities (FOCA) analysis was used to investigate the local consistency by integrating the temporal and spatial information of the local region. In the current study, resting-state fMRI data of 69 schizophrenia patients and 70 healthy controls were collected. FOCA was utilized to investigate the local consistency. Moreover, Granger causal analysis was used to investigate causal functional connectivity among these areas, which exhibited significantly different local consistency between groups. Compared with the healthy controls, the schizophrenia patients exhibited increased local consistency in hippocampus, basal ganglia and cerebellum regions, and decreased local consistency in sensoriperceptual cortex. In addition, altered causal functional connectivity was observed in hippocampo–cerebello-cortical (occipital) circuit. These findings suggested that this circuit might play a role in the motor dysfunction in schizophrenia, and should be paid more attention in future.

Progressive Reduction in Gray Matter in Patients with Schizophrenia Assessed with MR Imaging by Using Causal Network Analysis

Purpose To investigate the temporal and causal relationships of structural changes in the brain in patients with schizophrenia. Materials and Methods T1-weighted magnetic resonance (MR) images of 97 patients with schizophrenia (29 women; mean ± standard deviation age, 41 years ± 11.5; range, 16-66 years; illness duration, 16.3 years ± 10.9; range, 0-50 years) and 126 age- and sex-matched (38 years ± 14.9; range, 18-68 years; 42 women) healthy control subjects were evaluated. The causal network of structural covariance was used to assess the causal relationships of structural changes in patients with schizophrenia. This was accomplished by applying Granger causality analysis to the morphometric T1-weighted images ranked according to duration of disease. Results With greater disease duration, reduction in gray matter volume began in the thalamus and progressed to the frontal lobe, and then to the temporal and occipital cortices as well and the cerebellum (P < .00001, false discovery rate corrected). The thalamus was shown to be the primary hub of the directional network and exhibited positive causal effects on the frontal, temporal, and occipital regions as well as on the cerebellum (P < .05, false discovery rate corrected). The frontal regions, which were identified to be transitional points, projected causal effects to the occipital lobe, temporal regions, and the cerebellum and received causal effects from the thalamus (P < .05, false discovery rate corrected). Conclusion Schizophrenia shows progression of gray matter abnormalities over time, with the thalamus as the primary hub and the frontal regions as prominent nodes.

Common and distinct dysfunctional patterns contribute to triple network model in schizophrenia and depression: A preliminary study

BACKGROUND Schizophrenia (SCH) and depression (DEP) are prevalent psychiatric disorders and share common and distinguished elements in their pathophysiology. A triple network model composed of the default mode network (DMN), salience network (SN) and central executive network (CEN) may represent a major abnormality across several psychiatric disorders including SCH and DEP. However, common and distinct dysfunctional patterns between SCH and DEP across three core networks remain unclear. METHOD Resting-state functional magnetic resonance imaging (fMRI) was obtained in 20 patients with SCH, 20 patients with DEP and 20 healthy controls (HC). Both functional connectivity (FC) and Granger causal connectivity across DMN, SN and CEN were evaluated to uncover common and distinct dysfunctional patterns between SCH and DEP. RESULTS Two patient groups showed identical abnormal causal connectivity between key nodes of DMN and SN, as well as opposing aberrant FC of DMN-CEN and SN-CEN. Compared with HC, the FC between CEN and DMN was increased in SCH while decreased in DEP. Conversely, DEP showed enhanced FC between CEN and SN, whereas SCH showed decreased FC. LIMITATIONS The sample size was relatively small, and all participants were taking medication. CONCLUSIONS Our results identified common patterns including dysconnectivity between DMN and SN, which may contribute to shared cognitive and affective impairment in DEP and SCH. Moreover, opposing dysconnectivity patterns of DMN-CEN may be associated with different self-referential processing abnormalities. These opposing dysconnectivity patterns may indicate an unbalanced recruitment between SN and CEN. Therefore, this study provides dysconnectivity patterns to advance the understanding of the triple network model with regard to psychiatric disorders.

Transdiagnostic differences in the resting-state functional connectivity of the prefrontal cortex in depression and schizophrenia

BACKGROUND Depression and schizophrenia are two of the most serious psychiatric disorders. They share similar symptoms but the pathology-specific commonalities and differences remain unknown. This study was conducted to acquire a full picture of the functional alterations in schizophrenia and depression patients. METHODS The resting-state fMRI data from 20 patients with schizophrenia, 20 patients with depression and 20 healthy control subjects were collected. A data-driven approach that included local functional connectivity density (FCD) analysis combined with multivariate pattern analysis (MVPA) was used to compare the three groups. RESULTS Based on the results of the MVPA, the local FCD value in the orbitofrontal cortex (OFC) can differentiate depression patients from schizophrenia patients. The patients with depression had a higher local FCD value in the medial and anterior parts of the OFC than the subjects in the other two groups, which suggested altered abstract and reward reinforces processing in depression patients. Subsequent functional connectivity analysis indicated that the connection in the prefrontal cortex was significantly lower in people with schizophrenia compared to people with depression and healthy controls. LIMITATION The systematically different medications for schizophrenia and depression may have different effects on functional connectivity. CONCLUSIONS These results suggested that the resting-state functional connectivity pattern in the prefrontal cortex may be a transdiagnostic difference between depression and schizophrenia patients.

White-matter functional networks changes in patients with schizophrenia

ABSTRACT Resting‐state functional MRI (rsfMRI) is a useful technique for investigating the functional organization of human gray‐matter in neuroscience and neuropsychiatry. Nevertheless, most studies have demonstrated the functional connectivity and/or task‐related functional activity in the gray‐matter. White‐matter functional networks have been investigated in healthy subjects. Schizophrenia has been hypothesized to be a brain disorder involving insufficient or ineffective communication associated with white‐matter abnormalities. However, previous studies have mainly examined the structural architecture of white‐matter using MRI or diffusion tensor imaging and failed to uncover any dysfunctional connectivity within the white‐matter on rsfMRI. The current study used rsfMRI to evaluate white‐matter functional connectivity in a large cohort of ninety‐seven schizophrenia patients and 126 healthy controls. Ten large‐scale white‐matter networks were identified by a cluster analysis of voxel‐based white‐matter functional connectivity and classified into superficial, middle and deep layers of networks. Evaluation of the spontaneous oscillation of white‐matter networks and the functional connectivity between them showed that patients with schizophrenia had decreased amplitudes of low‐frequency oscillation and increased functional connectivity in the superficial perception‐motor networks. Additionally, we examined the interactions between white‐matter and gray‐matter networks. The superficial perception‐motor white‐matter network had decreased functional connectivity with the cortical perception‐motor gray‐matter networks. In contrast, the middle and deep white‐matter networks had increased functional connectivity with the superficial perception‐motor white‐matter network and the cortical perception‐motor gray‐matter network. Thus, we presumed that the disrupted association between the gray‐matter and white‐matter networks in the perception‐motor system may be compensated for through the middle‐deep white‐matter networks, which may be the foundation of the extensively disrupted connections in schizophrenia. HighlightsWhite‐matter FC was investigated based on resting‐state fMRI.Ten white‐matter networks were defined by clustering analysis on voxel‐wise FC.Abnormalities of perception‐motor white‐matter networks in schizophrenia.The disrupted associations between gray‐matter and white‐matter networks.

The Effects of Music Intervention on Functional Connectivity Strength of the Brain in Schizophrenia

Schizophrenia is often associated with behavior abnormality in the cognitive and affective domain. Music intervention is used as a complementary treatment for improving symptoms in patients with schizophrenia. However, the neurophysiological correlates of these remissions remain poorly understood. Here, we investigated the effects of music intervention in neural circuits through functional magnetic resonance imaging (fMRI) study in schizophrenic subjects. Under the standard care, patients were randomly assigned to music and non-music interventions (MTSZ, UMTSZ) for 1 month. Resting-state fMRI were acquired over three time points (baseline, 1 month, and 6 months later) in patients and analyzed using functional connectivity strength (FCS) and seed-based functional connection (FC) approaches. At baseline, compared with healthy controls, decreased FCS in the right middle temporal gyrus (MTG) was observed in patients. However, after music intervention, the functional circuitry of the right MTG, which was related with the function of emotion and sensorimotor, was improved in MTSZ. Furthermore, the FC increments were significantly correlated with the improvement of symptoms, while vanishing 6 months later. Together, these findings provided evidence that music intervention might positively modulate the functional connectivity of MTG in patients with schizophrenia; such changes might be associated with the observed therapeutic effects of music intervention on neurocognitive function. This trial is registered with ChiCTR-OPC-14005339.

Reconfiguration of Dynamic Functional Connectivity in Sensory and Perceptual System in Schizophrenia

Schizophrenia is thought as a self-disorder with dysfunctional brain connectivity. This self-disorder is often attributed to high-order cognitive impairment. Yet due to the frequent report of sensorial and perceptual deficits, it has been hypothesized that self-disorder in schizophrenia is dysfunctional communication between sensory and cognitive processes. To further verify this assumption, the present study comprehensively examined dynamic reconfigurations of resting-state functional connectivity (rsFC) in schizophrenia at voxel level, region level, and network levels (102 patients vs. 124 controls). We found patients who show consistently increased rsFC variability in sensory and perceptual system, including visual network, sensorimotor network, attention network, and thalamus at all the three levels. However, decreased variability in high-order networks, such as default mode network and frontal-parietal network were only consistently observed at region and network levels. Taken together, these findings highlighted the rudimentary role of elevated instability of information communication in sensory and perceptual system and attenuated whole-brain integration of high-order network in schizophrenia, which provided novel neural evidence to support the hypothesis of disrupted perceptual and cognitive function in schizophrenia. The foci of effects also highlighted that targeting perceptual deficits can be regarded as the key to enhance our understanding of pathophysiology in schizophrenia and promote new treatment intervention.