Cortical functional connectivity changes in amnestic mild cognitive impairment.

OBJECTIVE

Amnestic mild cognitive impairment (aMCI) is characterized by episodic memory deficits and is defined as the prodromal phase of Alzheimer's disease. Therefore, it is critical to reveal the dysfunction in large-scale networks during the dementia phase of the disease. This study aimed to examine the resting-state functional connectivity changes between aMCI and healthy control groups.

METHODS

MRI and clinical data from 25 individuals with aMCI and 25 healthy controls (HC) were used. Seed-to-seed functional connectivity analyses were performed between all histologically classified Brodmann areas using the CONN toolkit. False Discovery Rate (FDR) correction was used to correct for multiple comparisons, and the significance threshold was set at pFDR-corr < 0.05.

RESULTS

We found that, compared to HC, the aMCI group showed reduced functional connectivity between BA7 and both bilateral BA33 and right BA32, and these reductions were positively correlated with memory decline.

CONCLUSION

Our study suggests that the connectivity between the precuneus (BA7) and anterior cingulate cortex (BA32-33) is affected in the prodromal stage of Alzheimer's disease dementia. Investigating intrinsic functional connectivity changes between distant anatomical regions by using histological atlases might be useful for investigating the progress of dementia.