The Study Of Resting-state Neurocognitive Networks In Children And Adolescents With Idiopathic Generalized Epilepsy

Objective: To investigate the functional connectivity changes within core neurocognitive networks and between core neurocognitive networks in children and adolescents with idiopathic generalized epilepsy(IGE)using independent component analysis based –resting state functional magnetic imaging,and analyze the correlation between abnormal functional brain regions and duration and IQ,thus providing imaging evidence to better understanding the physiopathologic mechanism of cognitive dysfunction in children and adolescents with IGE.Methods: Twenty-four patients with IGE from the pediatric outpatient department and inpatient department in Affiliated Hospital of Zunyi Medical College from January 2014 to September 2016 were collected,and meanwhile 28 healthy children and adolescents were recruited as the control group.T2-FLAIR and rs-f MRI were performed with GE Signa HDxt 3.0T MRI in all subjects.The subject with IGE was performed China-Wechsler Intelligence Test(suitable for 6 to 17 years).All subjects were right handedness.Group independent component analysis(GICA)was performed to extract the core neurocognitive networks from the resting-state f MRI data.Seven resting state networks(RSNs)were identified in all subjects,including anterior default mode network(a DMN),superior-posterior default mode network(sp DMN),inferior-posterior default mode network(ip DMN),anterior salience network(a SN)and posterior salience network(p SN),left central executive network(l CEN)and right central executive network(r CEN).Intra-network functional connectivity analysis: for each network,one-sample t-test(p<0.05,family-wise-error,FWE corrected,cluster size > 20 voxels)was conducted in the control and patient group,respectively.Then,a spatial mask of each network was obtained by combining the spatial maps of the control and patient group.Finally,two-sample t-test(p < 0.05,false discovery rate,FDR corrected,cluster size>20 voxels)was conducted to explore significant RSN differences between the patient and control group in the masks.The correlation analysis was performed between significant RSN differences of patients and full scale intelligence quotient(IQ)and duration.Inter-network functional connectivity analysis: Pearson correlation analysis was performed between the seven networks.The Fisher r-to-z transformation was used to improve the normality of correlation coefficients.Then,one-sample t-test(p<0.05,uncorrected)was performed in each group to analysis the functional connection of time courses(TCs)among RSNs,and it was different from zero in at least one group.Among the significant connections of TCs,two-sample t-test(p < 0.05,uncorrected)was performed to analysis the significant group differences.The whole research protocol was approved by the Institutional Review Board and the informed consent was obtained from the patients or their guardian.Results: There wasn’t statistical difference in age,gender and degree of education between the control and IGE group.Intra-network functional connectivity: Compared with the control group,the IGE group showed decreased functional connectivity of DMN in bilateral medial superior frontal gyrus,dorsolateral superior frontal gyrus,superior frontal gyrus,medial orbita,precuneus and posterior cingulate gyrus,left middle frontal gyrus,and the increased functional connectivity of DMN in bilateral anterior cingulate and superior occipital gyrus,cuneus,right middle frontal gyrus and triangular inferior frontal gyrus.Correlation analysis showed that the mean connection strength of left medial superior frontal gyrus,left precuneus of the IGE group was positively related to IQ,respectively.Compared with the control group,the IGE group showed decreased functional connectivity of SN in bilateral medial superior frontal gyrus,anterior and median cingulate and paracingulate gyri,right insula,opercular part of right inferior frontal gyrus,right rolandic operculum and right putamen,increased functional connectivity in orbital part of bilateral inferior frontal gyrus,temporal pol of superior temporal gyrus,insula.The IGE group showed decreased functional connectivity of CEN in bilateral middle temporal gyrus and middle occipital gyrus,left inferior temporal gyrus,increased functional connectivity in the bilateral inferior parietal gyrus,supramarginal and angular gyri,left superior parietal gyrus.Correlation analysis showed that the connection strength of left angular gyrus of the IGE group was positively related to verbal IQ.Inter-network functional connectivity analysis: 17 significant connections,including 14 positive correlations(larger than zeros)and 3 negative correlations(less than zeros)were observed in the control group by using one-sample t-test.The IGE group demonstrated 10 significantly positive correlations(larger than zeros).Compared with the control group,the IGE group exhibited significantly decreased positive connections between the sp DMN and a DMN,between the a DMN and ip DMN,between the l CEN and a DMN,between the a DMN and r CEN.In addition,the functional connectivity between the sp DMN and a SN was negative in control group but positive in the IGE group.Conclusion: 1.Abnormal functional connectivity were exhibited in core neurocognitive networks,including default mode network(DMN),central executive network(CEN)and salience network(SN)in children and adolescents with IGE.Furthermore,correlation analysis showed some abnormal function connections have relation with IQ,providing informative evidence to better understanding the physiopathologic mechanism of cognitive dysfunction in children and adolescents with IGE.2.The DMN,SN and CEN networks were selectively impaired in children and adolescents with IGE.It may be a underlying physiopathologic mechanism of rupture of functional coordination and balance among core cognitive network in children and adolescents with IGE.