Abnormal Thalamocortical Functional Connectivity During Non-rapid Eye Movement Sleep In Children Suffer From Primary Nocturnal Enuresis Using Simultaneous EEG-fMRI Method

Objective: To non-invasively investigate abnormalities of thalamocortical functional connectivity(FC)in children with primary nocturnal enuresis(PNE)during nonrapid eye movement(NREM)sleep using simultaneous electroencephalography-functional magnetic resonance imaging(EEG–fMRI)method.Method and materials: EEG-MRI data were obtained from 20 PNE children(9 to 13 years,with median age of 11 years and 19 health controls(9 to 13 years,with median age of 11 years).Written informed consent was provided by all the participants' parents or legal guardians.All subjects participated in what Simultaneous EEG-fMRI studies were performed using a 3.0T MR system with a 32-channel MR-compatible EEG system.EEG-fMRI data were recorded during the participants' descent into sleep.Visual scoring of EEG data permitted sleep staging.Thalamocortical FC in different sleep stage of NREM sleep(N1,N2 and N3)were calculated separately.Statistical tests were performed using SPM.To investigate the effect of the within-subject factors of sleep stage(3 levels: N1,N2,N3)and group(PNE and control)on thalamocortical FC strength,a two-way repeated measures ANOVA was performed using the Z-scored FC measurements.Exploratory post-hoc paired t-tests were run to ascertain the direction of significant effects.Result: In the intergroup(PNE group and control group),the central posterior cortex showed a significant main effect of the grouping effect(peak point montreal neurological institute(MNI)coordinates: x = 39,y = 67,z = 38;number of pixels = 225;peak F1,120)= 25.23,P <0.01,FDR correction).In addition,the medial prefrontal cortex(mPFC)appears as an interaction between the sleep stage and the group(peak MNI coordinates: x=-5,y = 55,z = 21;number of pixels = 109;peak F1,120 = 18.93,P <0.01,FDR correction).Post-Hoc testing showed that mPFC thalamic-cortical FC was significantly lower in N3 than in the control group(t = 2.988,P = 0.017,Sidak correction)compared with the control group.Conclusion: The abnormal thalamocortical FC in postcentral cortex and mPFC duringNREM sleep may be related with abnormal sleep and enuresis in PNE children.