Examining Event-Related Brain Responses

We examined the event-related average (ERA) responses of functionally relevant ROIs extracted from the previous analyses. To this end, the mean BOLD signal time-courses of the DLPFC and ventral striatum were converted into PSC (signal variation relative to the average BOLD value during the “baseline” condition). Then, the time-course was segmented based on the onset and offset of each “Imagery” condition block (we considered two volumes before the onset and five after the end of each block to better understand the temporal profile of the response). Finally, we averaged these segments across trials and participants for each group, allowing for the between group comparison of the response of each brain region.