Objective:To investigate the mechanism of subjective cognitive decline(SCD)in resting-state by using regional homogeneity(ReHo)and functional connectivity(FC)in SCD patients.Methods:Resting-state functional magnetic resonance imaging(RS-fMRI)was performed in 25 SCD patients and 30 normal controls matched by sex, education and nationality.DPARSFA2.3 and SPM8 software were used to analyze and screen the brain areas with abnormal ReHo values in SCD group, with the posterior cingulated(PCC)/paruneus as seed points for whole-brain FC analysis.Results:Compared with the normal control group, the SCD group showed that ReHo values of right occipital gyrus and left precuneus were increased, and ReHo values of right inferior temporal gyrus, right orbital inferior frontal gyrus and bilateral thalamus were decreased(Voxel level, Alphasim correction, P<0.05). Using PCC/ precuneus as seed voxels, the whole brain functional connectivity analysis showed that the functional connectivity with cerebelum Crus 2 R was increased, and the functional connectivity with right orbital inferior frontal gyrus, left inferior temporal gyrus and temporal pole was reduced(Voxel level, Alphasim correction, all P<0.05). Conclusions:Default mode network may play an important role in the mechanism of SCD, and abnormalities in brain areas may first occur in PCC/precuneus.

Objective:To investigate regional homogeneity(ReHo)and whole brain functional connectivity(FC)in patients with mild cognitive impairment(MCI), and to explore the mechanisms of MCI in the resting state.Methods:Resting-state functional magnetic resonance imaging(RS-fMRI)was performed on 24 patients with MCI and 30 age, gender and nationality-matched normal controls.Abnormal brain areas in the MCI group were screened and analyzed by using the DPARSFA2.3 and SPM8 software programs.Whole brain FC analysis was performed with the posterior cingulate cortex(PCC)/precuneus as the seed points.Results:Compared with the control group, MCI subjects displayed higher ReHo values in the frontal-middle-Left, precentral-Left, postcentral-Left, rolandic-opercular-Left, and frontal-inferior-opercular-Left and lower ReHo values in the temporal-superior-right, temporal-middle-right, postcentral-right, and temporal -pole -superior -right(Voxel level, Alphasim correction, P<0.05). Whole brain FC analysis showed greater functional connectivity of PCC/precuneus with fusiform-right, thalamus-right, lingual-right and parahippocampal-right in subjects with MCI, and less functional connectivity of the PCC/precuneus with temporal-middle-Left, angular-Left, temporal-superior-Left and occipital-middle-Left in subjects with MCI(Voxel level, Alphasim correction, P<0.05). Conclusions:Abnormalities of the default mode network may be associated with the onset of MCI, and abnormalities in posterior cingulate/precuneus connectivity may be helpful in finding imaging evidence with high sensitivity to MCI.