Selective Functional Dysconnectivity In The Dorsolateral Prefrontal Cortex Subregions Of Low Sleep Efficiency In Major Depressive Disorder

Background: Sleep disturbance is a common and critical symptom in patients with major depressive disorder(MDD).The dorsolateral prefrontal cortex(DLPFC)is an important node of the frontoparietal network(FPN)and serves to an important neural substrate for depression.Based on high heterogeneity of the DLPFC,we were therefore interested in testing whether the resting-state functional connectivity(rs FC)of the DLPFC subregions is differentially affected in MDD with sleep disturbance.Methods: Ninety-six patients with MDD underwent resting-state functional and structure magnetic resonance imaging scans and overnight polysomnography examinations.The sleep efficiency(SE)of each patient was compared with 90% of the critical cutoff,patients were subdivided into well-matched normal sleep efficiency(NSE,N = 42;33% men;aged 43 ±10 years)and low sleep efficiency(LSE,N = 54;43% men;aged 45 ± 12 years)groups.The DLPFC subregions were defined according to a recent connectivity-based parcellation study using multimodal neuroimaging techniques and subdivided into 6 areas in each hemisphere.Seed-base functional connectivity analysis and Voxel-based morphometry(VBM)were performed to assess rs FC and gray matter volume(GMV)of each DLPFC subregion,respectively.The rs FC of each DLPFC subregion was compared between the two groups.The correlations between aberrant rs FC and clinical and cognitive parameters were evaluated.In addition,we examined the structure of the DLPFC subregions to determine whether the functional aberrations were accompanied by anatomical change.Results: Compared with the NSE group,the LSE group showed aberrant rs FC between several DLPFC subregions and multiple brain areas belong to the FPN,default mode network(DMN)and salience network(SN).These findings suggest that aberrant connectivity within the FPN,and aberrant interactions between the FPN and the DMN,SN are associated with low SE in MDD.There was no difference in gray matter volume of all the DLPFC subregions between two groups.In addition,these altered rs FC were still significant after controlling for the antidepressant types.Conclusion: 1.There is selective functional dysconnectivity in the DLPFC subregions of low SE in MDD.2.Low SE-related functional aberrations are not accompanied by structural alterations,which suggest a disassociation between structural and functional changes.The aberrant rs FC within and between the main hubs of the FPN,DMN,SN could potentially yield new insights into the link between MDD and sleep disturbance.