Hi Doug and Freesurfers,
I would like to calculate percent signal change within an anatomical ROI for a group of subjects in Freesurfer 5.0. We are not functionally constraining our ROI, however, we do want to calculate the percent signal change across the entire region in each of our conditions (the contrasts we are using are condition-vs-fixation). Below are examples of the commands I've run for one of our conditions:
funcroi-config -analysis SIRP_Stable5 -label lh.7Network_6.PFC.label -roi /cluster/roffman/users/Stable5_PerRun/ROI_Analysis/FB12/Anatomical_roicfg_103113/SIRP_lh_7Networks_6_PFC.roicfg
funcroi-sess -roi /cluster/roffman/users/Stable5_PerRun/ROI_Analysis/FB12/Anatomical_roicfg_103113/SIRP_lh_7Networks_6_PFC.roicfg -sf /cluster/roffman/users/Stable5_PerRun/Subject_Files/30_ActiveFolateAndPlacebo_PostPrePAIRED
funcroi-table-sess -roi /cluster/roffman/users/Stable5_PerRun/ROI_Analysis/FB12/Anatomical_roicfg_103113/SIRP_lh_7Networks_6_PFC.roicfg -sf /cluster/roffman/users/Stable5_PerRun/Subject_Files/30_ActiveFolateAndPlacebo_PostPrePAIRED -o /cluster/roffman/users/Stable5_PerRun/ROI_Analysis/FB12/Anatomical_roicfg_103113/18ActiveFolate_12Placebo_PreAndPost_7Tpost/lh_7Networks_6_PFC_1vFix -c Cond1vFix
Is it necessary to now generate the mean functional baseline offset value within the ROI in order to calculate percent signal change if our contrast is comparing condition-vs-fixation? Any clarification on when the offset value is needed would be greatly appreciated!
Thanks, Alex