ABSTRACT
Objective:To investigate the changes of default network functional connectivity (FC) in resting state of patients with insomnia disorder (ID).Methods:Fifty-six patients with insomnia disorder and fifty healthy controls were recruited. All subjects were assessed with Pittsburgh sleep quality index (PSQI), insomnia severity index (ISI), Epworth sleepiness score (ESS) and Hamilton depression scale (HAMD-17). All subjects were scanned with resting state functional magnetic resonance imaging (rs-fMRI). SPM12 and CONN18b were used to preprocess rs-fMRI data on MATLAB (R2013b).The medial superior frontal gyrus was defined as the seed point, and the differences in the functional connection strength of the two groups of subjects were compared. Pearson correlation analysis was performed between the FC value of the brain area with statistical significance and scores of PSQI and ISI.Results:(1)FC analysis showed that compared with the control group, patients with ID had abnormal default mode network (DMN) connection, as follows: FC of left medial superior frontal gyrus and left central anterior gyrus (MNI: x, y, z=-30, -15, 51) and anterior cingulate gyrus (MNI: x, y, z=-6, 24, 36), FC of right medial forehead between the last gyrus and the left central anterior gyrus (MNI: x, y, z=-48, -6, 48), FC of left anterior cuneiform and the left central back (MNI: x, y, z=-54, -18, 54) and left superior occipital gyrus (MNI: x, y, z=-21, -69, 30), FC of right precuneus and left central posterior gyrus (MNI: x, y, z=-60, -21, 48) was enhanced. The FC of left anterior cuneiform lobe and the right middle frontal gyrus (MNI: x, y, z=42, 33, 42) and the right angular gyrus (MNI: x, y, z=54, -51, 45), FC of right precuneus and left inferior temporal gyrus (MNI: x, y, z=-51, -12, -42) was weakened. (2)With the left medial superior frontal gyrus as the seed point, FC values in anterior cingulate gyrus ( r=0.451, 0.338, both P<0.01) and left anterior central gyrus ( r=0.324, 0.402, both P<0.05) were positively correlated with PSQI and ISI scores. With the right precuneus as the seed point, FC value of left posterior central gyrus was positively correlated with PSQI( r=0.333, P=0.013) and ISI scores( r=0.418, P=0.008), while FC value of left inferior temporal gyrus was negatively correlated with PSQI( r=-0.662, P=0.001) and ISI scores( r=-0.402, P<0.01).With the left precuneus as the seed point, FC value of left superior occipital gyrus was positively correlated with PSQI( r=0.438, P=0.001) and ISI scores( r=0.495, P=0.011). Conclusion:Patients with ID may have changes in the functional connection of multiple networks. The decrease of FC in DMN may be one of the potential causes of insomnia. The increase in FC between DMN and the visuospatial attention network may be the core of the mechanism of damage to the brain function network of insomnia link.