Aberrant spontaneous low-frequency brain activity in amnestic mild cognitive impairment: A meta-analysis of resting-state fMRI studies

Recent resting-state functional magnetic resonance imaging (rs-fMRI) studies have provided strong evidence of abnormal spontaneous brain activity in amnestic mild cognitive impairment (aMCI). However, the conclusions have been inconsistent. A meta-analysis of whole-brain rs-fMRI studies that measured differences in the amplitude of low-frequency fluctuations (ALFF) between aMCI patients and healthy controls was conducted using the Seed-based d Mapping software package. Twelve studies reporting 14 datasets were included in the meta-analysis. Compared to healthy controls, patients with aMCI showed decreased ALFFs in the bilateral precuneus/posterior cingulate cortices, bilateral frontoinsular cortices, left occipitotemporal cortex, and right supramarginal gyrus and increased ALFFs in the right lingual gyrus, left middle occipital gyrus, left hippocampus, and left inferior temporal gyrus. A meta-regression analysis demonstrated that the increased severity of cognitive impairment in aMCI patients was associated with greater decreases in ALFFs in the cuneus/precuneus cortices. Our comprehensive meta-analysis suggests that aMCI is associated with widespread aberrant regional spontaneous brain activity, predominantly involving the default mode, salience, and visual networks, which contributes to understanding its pathophysiology.