Frequency Specific Effects of ApoE ε4 Allele on Resting-State Networks in Nondemented Elders.

We applied resting-state functional magnetic resonance imaging (fMRI) to examine the Apolipoprotein E (ApoE) ε4 allele effects on functional connectivity of the default mode network (DMN) and the salience network (SN). Considering the frequency specific effects of functional connectivity, we decomposed the brain network time courses into two bands: 0.01-0.027 Hz and 0.027-0.08 Hz. All scans were acquired by the Alzheimer's Disease Neuroscience Initiative (ADNI). Thirty-two nondemented subjects were divided into two groups based on the presence (n = 16) or absence (n = 16) of the ApoE ε4 allele. We explored the frequency specific effects of ApoE ε4 allele on the default mode network (DMN) and the salience network (SN) functional connectivity. Compared to ε4 noncarriers, the DMN functional connectivity of ε4 carriers was significantly decreased while the SN functional connectivity of ε4 carriers was significantly increased. Many functional connectivities showed significant differences at the lower frequency band of 0.01-0.027 Hz or the higher frequency band of 0.027-0.08 Hz instead of the typical range of 0.01-0.08 Hz. The results indicated a frequency dependent effect of resting-state signals when investigating RSNs functional connectivity.