Figure 3.

SN/VTA BOLD responses of set and action phases: regional responses to each level of set and action were extracted using a functional ROI defined with an orthogonal contrast. a, The functional ROI for set was defined by the main effect of set over both its levels (240 voxels, p = 0.001, cluster FDR). b, The functional ROI for action was defined by the main effect of action over both its levels (186 voxels, p = 0.002, cluster FDR). Voxels within these functional ROIs were activated, as determined by small-volume correction using a predefined anatomical ROI based on mean normalized magnetization transfer across subjects. c, ROI analysis for the SN/VTA region across experimental phases. The SN/VTA activity was significantly larger when expecting an updating event (left bar, **p = 0.008), whereas the SN/VTA was slightly decreased on updating per se compared with maintenance (right bar, p = 0.127). An interaction between set and action in the SN/VTA was also evident (*p = 0.040). *p < 0.05; **p < 0.01.