fALFF

fALFF was calculated using DPARSF. Briefly, for a given voxel, the time series was first converted to the frequency domain using a “fast Fourier transform.” The square root of the power spectrum was computed and then averaged across a predefined frequency interval. This averaged square root was termed fALFF at the given voxel of predefined frequency bands (Zang et al., 2007a). We divided the full frequency range (0–0.25 Hz) into five sub-bands: slow-6 (0–0.01 Hz), slow-5 (0.01–0.027 Hz), slow-4 (0.027–0.073 Hz), slow-3 (0.073–0.198 Hz), and slow-2 (0.198–0.25 Hz) (35, 46, 30), and computed fALFF of each frequency bands.

Zang Y.-F., He Y., Zhu C.-Z., Cao Q.-J., Sui M.-Q., Liang M., et al. (2007a). Altered baseline brain activity in children with ADHD revealed by resting-state functional MRI. Brain Dev. 29 83–91. 10.1016/j.braindev.2006.07.002 [PubMed] [Cross Ref]