Fig. 4.

Effect of tDCS on pain ratings (NRS: 0–100). a Pain ratings during anodal tDCS. Anodal tDCS marginally improved pain inhibition by WM in the 2-back with pain task compared with its pre-tDCS baseline value. In contrast, pain and pain inhibition by WM in the 0-back task were not significantly different from their respective pre-tDCS baseline values (both p > 0.2). b Pain ratings during sham tDCS. Sham tDCS produced no significant change in pain intensity for any of the three tasks (all p > 0.2). Error bars SEM. Single asterisk indicates significant difference at p = 0.052