Three-way ANOVAs were conducted for each cluster to examine the effects of arousal (high, low), valence (positive, negative), and sensation seeking (HSS, LSS) on fMRI signal relative to the fixation baseline. The effects of arousal and valence were included to isolate any potential interactions between arousal and valence and between either arousal or valence and sensation seeking because the voxel-wise contrast did not test for such interactions. These initial ANOVAs were based on the average hemodynamic response in the 2.5-s to 7.5-s time window because ANOVAs conducted separately at each time point (from 2.5 to 15 s) did not reveal effects of sensation seeking or interactions outside this window. Clusters that showed a main effect of sensation seeking or an interactive effect involving sensation seeking (Table 1) served as regions of interest (ROIs) in additional analyses.
