Skip to main content
. Author manuscript; available in PMC: 2015 Feb 10.
Published in final edited form as: Neuroimage. 2013 Oct 4;84:672–680. doi: 10.1016/j.neuroimage.2013.09.057

Fig. 2.

Fig. 2

Estimation of CBF signals from pCASL data. Single-sided amplitude spectrum of (a) the initial ASL signal, (b) the high-pass filtered ASL signal, and (c) demodulated and high-pass filtered ASL signal. BOLD contamination of the CBF signal was substantially reduced using the procedure introduced in Chuang et al. (2008). However, within the frequency spectrum of the estimated CBF signal (i.e., 0–0.071 Hz), residual BOLD contamination might still be found in the range of 0.05–0.07 Hz (c). Therefore, in order to investigate the BOLD–CBF coupling during resting-state, we also tested the BOLD–CBF coupling using the CBF signal in the low-frequency oscillation range (LFO, 0.009–0.071 Hz) as well as the ultra-low frequency oscillation range (Ultra UFO, 0.009–0.05 Hz).