Spontaneous activities in Alzheimer’s disease explored by resting state functional magnetic resonance imaging

Abstract

Objective To investigate the characteristics of spontaneous activities throughout the whole brain with Alzheimer’s disease (AD) by resting state functional magnetic resonance imaging (fMRI). Methods The subjects included 23 AD patients and 21 normal controls（NC）, who underwent a neuropsychological test battery including MMSE and Auditory Verbal Learning Test (AVLT) and resting-state fMRI using GE Signa 3.0 T MR scanner. The neuropsychological scores were compared between two groups. Regional homogeneity (ReHo) method was used to explore the different regional spontaneous activities throughout the brain between normal controls and patients with AD. Results In AD group, clinical variables (MMSE scores: 20±4, AVLT-Immediate Recall: 2.6±1.6, AVLT-Delay Recall: 0.4±0.7, AVLT-Recognition: 5.8±3.7) were lower than NC group（29±1,5.9±1.2, 5.5±2.0, 9.2±1.1，T=10.58,7.21,10.99,3.96，all P<0.01）. With the threshold of P<0.01 for each voxel and a cluster size of at least 100 voxels, decreased ReHo indexes were found in default mode network (DMN) including the medial prefrontal cortex, posterior cingulate gyrus/precuneus, right superior temporal gyrus and bilateral superior parietal lobule/inferior parietal lobule in AD, while increased ReHo indexes were found in left putamen and thalamus compared with controls. Conclusion The DMN are damaged in AD and spontaneous activities of putamen and thalamus are reinforced as compensation response of subcortical structures. Key words: Alzheimer disease; Magnetic resonance imaging; Nerve net