4.To view and begin drawing an
ROI mask (or several ROIs) on this blank anatomical overlay
dataset, go to the main AFNI interface and [Switch Overlay] to
be the empty anatomical dataset you will be editing. Also turn the overlay ON with [See OverLay]
5.Start drawing the ROI mask
into this blank anatomical overlay dataset. Voxels inside the ROI mask
will receive a non-zero value (you decide what value to give them). Values outside the ROI mask will remain
zero
åBe sure to save the
results by pressing [Save], [SaveAs] or [DONE] in the ROI plugin GUI ([Quit] will exit the ROI plugin without saving your work)
6.Convert the
anatomical-resolution ROI dataset into a dataset at the resolution of the
functional (statistical) datasets you want to analyze with the ROI
åNote: The ROI and
functional datasets may already be at the same resolution, if you are
operating in +tlrc coordinates
åResolution
conversion of masks is done with program 3dfractionize
7.Use programs 3dmaskave, 3dmaskdump, and 3dROIstats to extract ROI-based information
about functional datasets
åAlso can use the ROI Average plugin to extract interactively the average of a dataset over
a ROI