Hi: We're trying to do a correlation analysis between BOLD % Signal Change and behavioral performance. The fMRI data is being analyzed using freesurfer (specifically, the program roisummary-sess, see https://surfer.nmr.mgh.harvard.edu/fswiki/roisummary_2dsess? action=highlight&value=roisummary-sess). This program outputs a couple values (detailed on that page), notably, the number of voxels in the area, the number that were active above statistical threshold, and the "mean functional baseline offset". Unfortunately, since I am a novice in Freesurgfe, it's unclear to me how to get a % signal change from this data. Presumably, the offset value says something about the difference in activity between the on and off periods, but I don't know the exact meaning of this value, and how to get a % signal change from it.
We get a single output file per run (~280s) and have 12 runs total (8 on day 1, 6 on day 2). We have various behavior metrics corresponding to each of these.
I'm attaching one of the output files here. Thanks a lot! Lucia
n002-task-3-008 98 32 1093.3451 8.9397 76.000000 3.300000 0.000000 1 1 7.8309