Relationship Between Default Mode Network Functional Connectivity And Cognitive Function In First-episode Schizophrenia

BackgroundSchizophrenia is a serious mental illness with negative symptoms,positive symptoms and impaired cognitive function.Among them,cognitive impairment is the core symptom of schizophrenia,which causes social function decline and affects the prognosis of patients and further lead to a heavy burden to the family and society.However,the pathogenesis of cognitive impairment is unclear.Patients with schizophrenia have abnormal brain structure and function,and the brain is a complex network structure composed of multiple brain regions.Integration abnormalities between multiple brain regions can properly explain the disease characteristics of schizophrenia.Among them,the default network(DMN)is a hot spot in recent years.Resting-state functional magnetic resonance imaging(rs-fMRI)is a new magnetic resonance technique that has been developed in recent years to detect functional status and changes in the brain.The whole brain functional connectivity analysis based on the region of interest is used as a data for fMRI.The analysis method can analyze the functional connection changes of the default network in the resting state of the brain,thereby expounding the holistic properties of the whole brain network and revealing the neural network of the brain network.Objectives1.Analysis of psychiatric symptom and cognitive impairment in first-episode schizophrenia patients;2.To explore the default network function connection abnormal changes in patients with first-episode schizophrenia;3.To observe the relationship between the default network abnormal function connection and clinical psychotic symptoms and cognitive dysfunction in patients with first-episode schizophrenia.Methods79 first-episode patients with schizophrenia(case group)were chosen from the clinics and wards of Psychiatry the First Affiliated Hospital of Zhengzhou University from January 2017 to September 2018.The diagnosis was in accordance with DSM-?.Meanwhile,80 healthy volunteers suited to age as well as gender and years of education were chosen(normal control group).To obtain detailed medical history and collect clinic data from case group.To evaluate psychiatric symptoms by PANSS.All subjects were scanned rs-fMRI,At the same time,cognitive function were assessed by MCCB.We adopted a seed-based analysis method and chose PCC?LPC and MPFC as ROIs to research their FC with other regions of the brain.Finally,the z value of the functional connection was obtained.Finally,the two-sample t-test was used to compare the default network(DMN)functional connection between the patient group and the control group,and the z-value of the abnormal functionconnected brain region was correlated with the cognitive function and clinical psychotic symptoms of the patient.Results1.A total of 79 cases were enrolled in the case group(6 patients were excluded,73 patients were eventually included),and 80 cases in the control group(9 patients were excluded,71 patients were eventually included).The basic information of age,education level,gender and smoking history were no significant differences between normal control group and case group(P>0.05)2.In comparison with the control group scores[SOP(52.8±9.3)?CPT-IP(51.9±8.7)?WMS-?(56.6±11.1)?HVLT(51.3±10.5)?BVMT(57.3±12.0)?NAB(46.9±10.0)?MSCEIT(56.7±14.1)] were significantly higher in the seven domains of cognitive function in the schizophrenia group[SOP(26.9±11.4)?CPT-IP(29.7±12.8)?WMS-?(39.3±11.7)?HVLT(37.1±9.7)?BVMT(38.7±15.5)?NAB(34.8±10.0)?MSCEIT(33.5±9.7)].(P<0.001)3.We discovered extensive abnormalities in the DMN FCs of the first-episode schizophrenia.The abnormal brain regions include the temporal lobe,cerebellum,marginal lobes,dorsolateral prefrontal cortex,hippocampus,and occipital lobe.4.The first-episode schizophrenia patients show both enhanced and reduced FCs of PCC : Contrasted to the healthy control group,Decreased FCs between the PCC and posterior cerebellar lobes,marginal lobes,right insula,prefrontal cortex,right superior frontal gyrus dorsolateral exist in the case group.PCC had increased FCs with right orbital inferior frontal gyrus,temporal lobe,left insula,left triangular inferior frontal gyrus,right putamen,right triangular inferior frontal gyrus,right supplementary motor area,and right middle frontal gyrus.5.The first-episode schizophrenia patients manifest both intensive and subdued FCs of MPFC: The FC was strengthened between the MPFC and Lentiform nucleus,middle frontal gyrus,thalamus,right supplementary motor area;MPFC had decreased FCs with right inferior occipital gyrus.6.The first-episode schizophrenia patients show both intensive and subdued FCs of LPC: Contrasted to the healthy control group,the patient group had strengthened FCs between the LPC and right orbital inferior frontal gyrus,right putamen,parahippocampal gyrus,prefrontal lobe,left insula,cingulate gyrus.LPC had only decreased FCs with posterior cerebellar lobes,superior temporal gyrus.7.Connection between aberrant DMN FCs and clinical psychotic symptomsThe aberrant DMN FCs are connected with clinical variables.Within the first-episode schizophrenia patients group,the enhanced FC between the PCC and right orbital inferior frontal gyrus was positive correlations with the negative symptom scores.The reduced FC between the PCC and right putamen was positive correlations with the positive symptom scores 8.Connection between aberrant DMN FCs and cognitive dysfunctionThe aberrant FCs of DMN and abnormal cognitive function indicated that the intensive FCs between the PCC and temporal lobe(right inferior temporal gyrus and right middle temporal gyrus)was positive correlations with information processing rate T scores?verbal lea8 rning T scores?working memory T scores?attention/alert T scores?visual learning T scores?reasoning and problem solving T scores.;The increased FCs between the PCC and left insula,left triangular inferior frontal gyrus were positively related to visual learning T scores;The decreased FCs between the PCC and right superior frontal gyrus dorsolateral was negatively correlated with visual learning T scores;The enganced FCs between the MPFC and middle frontal gyrus was positively related to verbal learning T scores?visual learning T scores.The decreased FCs between the LPC and superior temporal gyrus was negatively related to working memory T scores and reasoning and problem solving T scores.Conclusions1.Patients with first-episode schizophrenia have cognitive impairment,mainly in information processing speed,working memory and social cognition.2.Patients with first-episode schizophrenia have abnormal FCs in the DMN,It is speculated that abnormal FCs of DMN may be the basis of characteristic brain network in patients with schizophrenia.3.The abnormal function connection of DMN in patients with first-episode schizophrenia may be one of the imaging indicators that may help diagnosis.