PMC

A hybrid-design paradigm was used. Each money condition contained six blocks (red for low-money condition and blue for high-money condition), with a 5 s rest between each block. Before each block, there was a 6 s cue to inform participants of the financial situation of pain targets (how much money they got) in this block. In each block, four painful pictures and four non-painful pictures randomly presented with null trials, each lasting 3.5 s. The interstimulus intervals (ISI) were jittered from 0.5 to 1.5 s. A black fixation cross was presented during the intervals and null trials. Different money condition blocks were alternate between each other and the presentation order of the blocks sequence being counterbalanced across participants.

(A) Regions of interest [M aMCC (0 27 33), L aMCC (−3 12 42), bilateral insula (L: −36 12 0; R: 33 21 −9), L PCG (−27 −39 60) and R TPJ (60 −28 28)] based on previous studies. L = left hemisphere; R = right hemisphere. (B) Beta estimates for all four trial types in each ROI, showing greater BOLD signal change in the low-money condition than that in the high-money condition. Error bars indicate s.e.m.