A Resting-state Functional Magnetic Resonance Imaging Study On Primary Insomnia Patients

Objective:To investigate the difference of cerebral Functional Connectivity and Regional Homogeneity ofprimary insomnia patients using functional Magnetic Resonance Imaging in resting-state, and toexplore the neurophysiological mechanisms of primary insomnia on the basis of neuroimaging.Methods：Bold-fMRI scan were performed in twenty one primary insomnia patients and twenty age-andsex-matched healthy volunteers in resting state. Patients were selected with the diagnosticcriteria of primary insomnia according the diagnostic and statistical manual of mental diseases(DSM-IV) developed by American psychiatric association. Data were analyzed by SPM software:a) the difference of functional connectivity between the region of interest and posteriorcingulated gyrus (PCC) was analyzed by voxel-wise; b) post-processing method was used tocompare the regional homogeneity difference of brain regions between the two groups.Two-sample t test were performed to analyze the statistical differences.Results:Compared with the matched group, significant increased functional connectivity were found inbilateral gyrus frontalis medius, bilateral posterior gyrus cinguli, bilateral precuneus, rightsuperior parietal lobule and right posterior central gyrus; and the functional connectivity weresignificantly decreased in left praecuneus, right parietal lobe sub-gyral in primary insomniapatients. The brain areas with significant higher ReHo value in primary insomnia patients wereas follow: the left side of pons, right parahippocampal gyrus, left calcarine sulcus cortex, leftlobus insularis cortex, bilateral anterior cingulate cortex and left precuneus; and ReHo value wassignificantly decreased in the bilateral of inside back of the prefrontal, bilateral cuneus, rightprecuneus and bilateral posterior central gyrus.Conclusion:a) Compared with healthy group, we found that there were some brain regions of abnormalfunction connected with the bilateral posterior cingulate in primary insomnia patients inresting state, and these regions are part of the default mode network, which suggesting that these areas with the abnormal functional connectivity played an important role in thepathophysiology mechanism of primary insomnia.b) The abnormal brain areas of primary insomnia patients are most in the struct of the limbicsystem, such as the back of the prefrontal, parahippocampal gyrus, cingulate gyrus, whichsuggesting that brain dysfunction or injury may exist in these regions.c) The primary insomnia patients suffer from circadian system disorders, according to theexperimental results suggest that the impairment of the reticular system caused by thehyperarousal of insomnia patients are related of this process.