Functional Changes Of Different Brain Regions In Mild Cognitive Impairment Based On Resting State Functional Magnetic Resonance Imaging

PART ONE: Regional homogeneity in patients with mild cognitive impairment:a resting-state functional magnetic resonance imaging study Objective:To analyze the potential changes in brain neural networks in resting state functional magnetic resonance imaging(rs-f MRI)scans by regional homogeneity(Re Ho)in patients with mild cognitive impairment(MCI).Methods:We recruited and selected 24 volunteers,including 12 patients(6 men and 6women)with MCI and 12 healthy controls matched by age,sex,and lifestyle.All subjects were examined with rs-f MRI to evaluate changes in neural network connectivity,and the data were analyzed by Re Ho method.Correlation analysis was used to investigate the relationship between Re Ho values and clinical features in different brain regions of MCI patients.The severity of MCI was determined by the mini-mental state examination(MMSE)scale.Results:The Re Ho values of the right cerebellum areas 4 and 5,left superior temporal,right superior temporal,left fusiform,and left orbital middle frontal gyri in the patient group were significantly higher than those in the control group.The Re Ho values of the right inferior temporal and left inferior temporal gyri were significantly lower than that of the control group.The Re Ho value for the left inferior temporal gyrus correlated negatively with disease duration,and the value for the right inferior temporal gyrus correlated positively with MMSE scores.Conclusion:Mild cognitive impairment may be related to the excitation and inhibition of neural networks in these regions.This may have a certain guiding significance for clinical diagnosis and prognosis.PART TWO: A functional MRI study of altered spontaneous brain activity pattern in patients with mild cognitive impairment using amplitude of low-frequency fluctuationObjective:The search for accurate and safe methods to detect early Alzheimer’s disease(AD)has become a major research focus.This study aims to use the amplitude of low frequency fluctuation(ALFF)analysis method to explore the changes in baseline brain activity of patients with mild cognitive impairment(MCI)as a precursor to AD.Methods:Twelve patients with MCI and 12 healthy controls(HCs)similar in age and gender were enrolled in this study.All participants underwent resting-state functional magnetic resonance imaging scans(rs-f MRI)and the ALFF analysis technique was used to observe differences in spontaneous brain activity.Receiver operating characteristic(ROC)curves were used to analyze ALFF values in specific regions of the brain.Correlations between ALFF values and clinical variables in patients with MCI were analyzed using Pearson’s correlation coefficient.Results:Compared with healthy controls,MCI patients had significantly lower ALFF values in the left cerebelum-9,left fusiform gyrus,left insula and higher values in the left middle temporal gyrus and right superior temporal gyrus.Conclusion:Manifestations of MCI are related to dysfunction of brain regions linked to memory,language,learning,movement,and executive function.This relationship may reflect potential pathogenic mechanisms of MCI.