HANDS-ON EXAMPLES FOR ROI DEMO --------------------------------- --------------------------------- cd AFNI_data6/roi_demo ------------------------------------------------------------------- ------------------------------------------------------------------- 3dresample: RESAMPLE ROI MASK FROM HIGH RES TO LOW RESOLUTION (1) 3dresample -master rall_vr+orig -prefix anat_roi_resam \ -inset anat_roi+orig -rmode NN ------------------------------------------------------------------- ------------------------------------------------------------------- 3dmaskave: USE THE RESAMPLED MASK ON A 3D+TIME DATASET TO COMPUTE A MEAN VALUE FOR THE VOXELS THAT FALL WITHIN THE MASK AT EACH TIMEPOINT (124 TIMEPTS IN THIS E.G.) (2a) 3dmaskave -mask anat_roi_resam+orig -q rall_vr+orig > epi_avg.1D (2b) 1dplot -yaxis 1000:1200:2:1 epi_avg.1D ------------------------------------------------------------------- ------------------------------------------------------------------- 3dmaskdump: USE THE RESAMPLED MASK ON A FUNCTIONAL DATASET. IN THIS E.G., WE ARE SELECTING A SPECIFIC SUB-BRICK IN OUR FUNC DSET (e.g., SUB-BRICK #2, T-VALUES FOR "VISUALLY RELIABLE" (Vrel) STIMULi) AND 'DUMPING' ONLY THE T-STATS FOR 'Vrel' FOR THE VOXELS THAT FALL WITHIN THE ROI MASK (3a) 3dmaskdump -noijk -mask anat_roi_resam+orig 'func_slim+orig[2]' \ > Vrel-tstats.txt (3b) more Vrel-tstats.txt NOTE: YOU CAN DO THIS WITH MORE THAN 1 SUB-BRICK AT A TIME. E.G., (3c) 3dmaskdump -noijk -mask anat_roi_resam+orig \ 'func_slim+orig[1,2]' > Vrel_beta_t.txt (3d) more Vrel_beta_t.txt ------------------------------------------------------------------- ------------------------------------------------------------------- 3dROIstats: COMPUTE A MEAN FOR VOXELS IN AN ROI MASK. CAN BE ANAT ROI OR FUNC ROI. DIFFERENT FROM 3DMASKAVE - WITH 3dmaskave, IF YOU HAVE A MASK WITH >1 ROI IN IT, THIS PROGRAM WILL COLLAPSE THOSE ROIS AND COMPUTE ONE GRAND MEAN. - WITH 3dROIstats,IF YOU HAVE A MASKE WITH >1 ROI IN IT, THIS PROGRAM WILL COMPUTE INVIDIDUAL MEANS FOR EACH ROI. (4) 3dROIstats -mask 3rois+orig func_slim+orig.'[0]' ------------------------------------------------------------------- ------------------------------------------------------------------- CREATE A FUNCTIONAL ROI MASK, USING A FUNC DATASET AS OUR GUIDE (RATHER THAN AN ANATOMICAL UNDERLAY) YOU MUST OPEN THE FUNC DSET, SELECT THE SUB-BRICK OF INTEREST, SET A THRESHOLD (TO KEEP ONLY THE CLUSTERS THAT SURVIVE THE THRESHOLD) & DECIDE HOW BIG YOU WANT THOSE FUNC CLUSTERS TO BE. 3dclust: 3DCLUST SHOWS YOU A LIST OF CLUSTERS THAT SURVIVE THE CRITERIA YOU'VE SET -1clip sets threshold the user selects, e.g., F>=99, rmm=1 (voxels have to touch to be part of the cluster), vmul 200 (1x1x1x200=200)) (5a) 3dclust -dxyz=1 -1clip 99 1.0 200 func_slim+orig.'[0]' 3dmerge: 3DMERGE CREATES AN AFNI DATASET OF THE CLUSTERS THAT HAVE SURVIVED THE CRITERIA YOU'VE SET (5b) 3dmerge -prefix func_roi -dxyz=1 -1clip 99 -1clust_order 1 200 \ func_slim+orig.'[0]' ------------------------------------------------------------------- ------------------------------------------------------------------- whereami: CREATE AN ROI DATASET USING VARIOUS ATLASES AVAILABLE WITH THE AFNI PROGRAM whereami (BUT FIRST CREATE A CLUSTER WITH 3DCLUST AND SAVE IT AS A 1D (TXT) FILE): (6) 3dclust -dxyz=1 -1clip 99 1 200 func_fullF+tlrc > clusts.1D whereami -coord_file clusts.1D'[1,2,3]' -tab | less ------------------------------------------------------------------- ------------------------------------------------------------------- whereami: EXTRACT ROIS FOR VARIOUS ATLAS REGIONS USING SYMBOLIC NOTATION (7) whereami -mask_atlas_region TT_Daemon:left:amy ------------------------------------------------------------------- ------------------------------------------------------------------- whereami: REPORT ON THE OVERLAP OF ROIS WITH ATLAS-DEFINED REGIONS (8) whereami -omask anat_roi+tlrc ------------------------------------------------------------------- ------------------------------------------------------------------- more on ROIs: SPECIFY ATLAS-BASED ROI MASKS DIRECTLY LIKE THIS: (9a) 3dmaskave -mask TT_Daemon:left:hippocampus func_fullF_1mm+tlrc (9b) 3dcalc -a 'CA_N27_ML::hippo' -b 'func_fullF_1mm+tlrc' \ -expr '(step(a)*b)' -prefix nice_roi (9c) 3dcalc -a 'TT_Daemon::amygdala' -b 'CA_N27_ML::amygdala' \ -expr 'step(a)+2*step(b)' -prefix compare.maps