Figure 3.
fMRI results related to expected reward magnitudes: ventral striatum. Significant (p < 0.05 FDR corrected) bilateral ventral striatal fMRI involvement as revealed by the repeated measures ANOVA 1 over the whole trial with eight conditions (A: 25%-120¢, B: 25%-60¢, C: 50%-60¢, D: 50%-30¢, E: 75%-40¢, F: 75%-20¢, G: 100%-30¢, H: 100%-15¢) set up to model effects of different reward magnitude. On the right panel, time courses (1st eigenvariate of the fMRI signal intensity as provided by standard SPM functions and standard errors) in significant voxels of left and right ventral striatum are demonstrated. Mean-corrected fMRI signal time courses were extracted for each subject and were averaged event-related to depict the fMRI signal. Grey shades indicate the period when reward expectation took place relative to the delayed MR signal. The fMRI signal peaks around scan 7 after onset of the trial (scan 1) with significantly (p < 0.005) higher values for scan 7 than for scan 3 in all eight conditions.