Degree Centrality Of The Functional Network In Adolescents Patients With First Episode Major Depressed Disorder With Suicidal Ideation

Background and purposeMajor Disorder Disease(MDD)is a kind of mood disorder,one of the most common mental illness,with loss of interest and decreased activity as the main clinical symptoms.Adolescent depression will lead to their mental sub-health,and result in the occurrence of adverse events,such as obesity,smoking and drug abuse,due to the lack of appropriate adjustment.When adolescent MDD has disorder badly,it may lead to serious psychological pressure to the patient and some financial burden to the family.Adolescent depression is often accompanied by serious suicidal thoughts and self-harm behavior,which is the third cause of death at this age.Assessment of suicidal ideation and early intervention can effectively prevent the suicide death of depression patients.Taking first-episode drug-naive patients with depression as the research object,we can eliminate the influence of confounding factors brought by medication and observe the early changes of the disease.In recent years,degree centrality(DC)has caused wide public concern.The DC is one of the most valuable explorative methods for analyzing resting-state fMRI and it is on the basis of the principle of graph theory in the brain network measurement method.Among numerous centrality measures,we chose degree centrality for its simplicity in understanding and performance.For a given node i in a binary graph,degree centrality is calculated as the number of edges connecting to it,while in a weighed graph,it is computed as the sum of weights over these edges.Compared with binary degree centrality,its weighted version provides a more precise centrality characterization of functional brain networks by taking connection weights into account.In this research,the DC was used to investigate the changes of the core nodes of resting-state brain network in first-episode adolescent patients of MDD with or without suicidal ideation,and to analyze the relationship between the degree centrality of different brain regions and degree of depression,the grades of suicidal ideation and suicidal risk between the depression group and the healthy control group.Materials and methods1.We used GE Discovery 750 3.0T MR scanner.The scaning sequence included conventional MRI head scan and resting BOLD sequence.In this study,we collected 33 first-episode untreated MDD adolescent patients with suicidal ideation,11 first-episode untreated MDD adolescent patients without suicidal ideation and 33 healthy controls.Clinical information of all subjects were collected including basic information,Beck Scale for Suicide Ideation and Hamilton rating scale for depression of patients and healthy controls.2.DPARSFA was used to preprocess the resting state fMRI data.The process included some steps.To be specific,they were data format conversion,excluding time points,slice timing,realignment,and spacial normalization.At the same time,the age and education level were used as covariates.3.Using DPARSF software was to calculate voxel-oriented degree centrality values.Specifically,for each voxel,its time series was first extracted and then correlated against the time courses of all other voxels in a study-specific brain mask.After finishing these analyses for each voxel in the mask,a weighted centrality map was finally derived for each participant,with the value at a given voxel reflecting the extent to which the voxel functionally integrates with other voxels in the brain.Voxels with higher degree centrality are considered more important in maintaining network integrity and performance.Finally,all the resulting centrality maps were further spatially smoothed(a Gaussian kernel with a full-width at half maximum=6 mm).4.One-Way ANOVA was performed on the MDD with or without suicidal ideation group and the control group using the SPM8 software based on the Matlab platform.We used SPSS 22.0 software in order to compare the clinical features between the first episode MDD with or without suicidal ideation and the healthy control.Besides,we also used SPSS to analyze the correlation between abnormal DC values and the grades of suicidal ideation and suicidal risk.Results1.Clinical data analysis showed that compared to healthy control group,the first episode MDD with or without suicidal ideation group in education years(10,11,11)and HAMD scores(39.70±10.593,33.09±10.765,3.33±1.744)had statistical difference(P<0.05).But there was no statistical difference in gender between the first episode MDD with or without suicidal ideation group and the healthy control group(P>0.05).2.The increase of DC values in the first episode MDD with suicidal ideat ion group were mainly in the superior parietal gyrus(F=3.45,P=0.000),tempor al lobe(F=4.75,P=0.001),precuneus(F=3.78,P=0.001)and cuneus(F=5.19,P=0.001).The DC values in the limbic lobe(F=4.76,P=0.001)and insula(F=3.24,P=0.000)were decreased.Compared to the HC,MDD without suicidal ideation showed higher DC values in the superior parietal gyrus(F=-3.63,P=0.000),tem poral lobe(F=3.76,P=0.001),precuneus(F=2.96,P=0.007)and occipital lobe(F=3.21,P=0.000)and lower DC values in the limbic lobe(F=4.06,P=0.001)and insula(F=3.20,P=0.000).Compared to the MDD-NI,the DC values of MDD-S I in the frontal lobe(F=-4.61,P=0.009)were decreased(P<0.05,FWE correcte d).3.Spearman rank correlation analysis was conducted between the brain areas with DC differences and the clinical scale indicators.The results showed that the DC value of precuneus(r=0.770,P= 0.000)and parahippocampal gyrus(r=0.853,P=0.000)in the first episode MDD with suicidal ideation group were positively correlated with the scores of HAMD-24,but the correlation between DC values and the factors of suicidal ideation and suicidal risk had no statistical significance(P>0.05).Conclusions1.This study found that the first episode MDD with suicidal ideation patients had abnormal degree centrality values in different brain areas,including the superior parietal gyrus,temporal lobe,precuneus,cuneus,limbic lobe and insula.Compared to the MDD-NI,MDD-SI had abnormal degree centrality values in the frontal lobe.It was based on the voxel correlation analysis.2.The results showed that the DC value of precuneus and parahippocampal gyrus in the first episode MDD with suicidal ideation group were positively correlated with the scores of HAMD-24,but the correlation between DC values and the factors of suicidal ideation and suicidal risk had no statistical significance(P>0.05).