Abnormal Connectivity Patterns Of Core Networks Between Schizophrenia And Depression

Schizophrenia,as the most prevalent serious mental disease,is mainly characterized by the emotional,behavioral,thinking,perceptional disorders.Patients with schizophrenia have some cognitive and emotional impairments.Depression,as one of the most common psychological and emotional disorders,is caused by a variety of different reasons,which is characterized by lasting unhappy and anxious.Depressive disorder patients have high incidence rate,high recurrence rate,high suicide rate and high self-disability.As the two most prevalent mental illnesses,schizophrenia and depression share some common and different clinical features.In recent years,the use of functional magnetic resonance imaging techniques find that abnormal connectivity in brain may be a pathophysiological mechanism of mental illness.Investigating the information flow and functional integration between different brain regions is very important to understand the pathophysiological mechanism of mental illness.In particular,the cognitive core network model,focused to exploring the common and specificity between diseases,which implies that a variety of mental diseases may be as a result of endogenous and external information exchange in an abnormal way.The model considers that the abnormal connectivity across default mode network,salience network and central executive network is a major pathophysiological mechanism in mental illness.However,few study have focused on common and distinct dysfunctional patterns across three core networks between schizophrenia and depression.Using this model as the starting point and the foothold,this study investigated the connectivity across default mode network,salience network and central executive network.By both functional connectivity analysis and the Granger causality analysis to evaluate the information integration and information flow across networks.In this study,functional magnetic resonance image data of 20 subjects in each group of patients with schizophrenia,depressive disorder patients and healthy subjects were collected.First,According to priori information,we determined key nodes of the default mode network and the central executive network.Based on the whole brain functional connection profiles,K-means clustering method was used to divide whole insula into three sub-regions.Then,the right dorsal anterior insula was defined as the seed of salience network.And seed-based functional connectivity analysis was used to define the spatial distribution of three core networks.Then we calculated the functional connectivity and Granger causal connectivity between the seed and other voxels within three networks.Finally,partial correlation analysis was used to explore the relationship between altered connectivity and clinical data.In this study,we find that there are common and distinct dysfunctional connectivity patterns between two disorders.At the level of functional connectivity,opposing dysconnectivity patterns between default mode network and central executive network were observed.Compared with healthy controls,the functional connectivity between dorsal lateral prefrontal cortex and medial prefrontal cortex as well as posterior cingulate cortex and inferior frontal cortex were increased in schizophrenia group and decreased in depressive patient group,which might associate with the abnormality of self-referential processing and reflect the different manifestations of dysfunctions of self-reference: extensively attributed to the self in depression and reduced self-attribution in schizophrenia.At the level of effective connectivity,we found common dysconnectivity patterns between default mode network and salience network.Compared with healthy controls,both patient groups showed increased effective connectivity from posterior cingulate cortex to dorsal anterior insula as well as temporoparietal junction region and reduced effective connectivity from dorsal anterior insula to posterior cingulate cortex.The abnormal effective connectivity reflected parallel defects of dynamic information exchange,which might contribute to common cognitive and affective impairments in both disorders.