Experimental design: 20 min of anodal, cathodal, and sham tDCS was applied on 3 consecutive days. On day 1, pCASL sequences were collected before the tDCS (pCASL (pre)), during the tDCS (beginning ~6 min into the stimulation; tDCS pCASL (during)), and after the tDCS (pCASL (post)). On day 2, the participants received only the tDCS treatment, and no MRI data were acquired. On day 3, pCASL scans were acquired before the tDCS (pCASL (pre)), and during the tDCS (beginning ~6 min into the stimulation; tDCS pCASL (during)). rs-fMRI: resting-state fMRI; pCASL: pulsed continuous arterial spin labeling.