Background: Subjective Memory Impairment (SMI) may tremendously increase the risk of
Alzheimer’s Disease (AD). The full understanding of the neuromechanism of SMI will shed light on
the early intervention of AD.
Methods: In the current study, 23 Healthy Controls (HC), 22 SMI subjects and 24 amnestic Mild Cognitive
Impairment (aMCI) subjects underwent the comprehensive neuropsychological assessment and
the resting-state functional magnetic resonance imaging scan. The difference in the connectivity of the
Default Mode Network (DMN) and Functional Connectivity (FC) from the Region of Interest (ROI) to
the whole brain were compared, respectively.
Results: The results showed that HC and SMI subjects had significantly higher connectivity in the region
of the precuneus area compared to aMCI subjects. However, from this region to the whole brain,
SMI and aMCI subjects had significant FC decrease in the right anterior cingulum, left superior frontal
and left medial superior frontal gyrus compared to HC. In addition, this FC change was significantly
correlated with the cognitive function decline in participants.
Conclusion: Our study indicated that SMI subjects had relatively intact DMN connectivity but impaired
FC between the anterior and posterior brain. The findings suggest that long-distance FC is more
vulnerable than the short ones in the people with SMI.