Dear all,

I am interested in comparing ROI-based results with vs. without the application of global signal regression (GSR).
In other words, I am more interested in the signal component of the global signal, and not so much in the noise.

AFNI proc allows to run GSR via the option

-regress_roi brain

I assume that this option computes the global signal by taking all voxels of the brain. Is there a way to apply GSR based on a specific ROI?
Phrased differently, instead of computing the global signal (an average time-series) based on all voxels’ time-series, is there an option to regress the global signal based on a specific ROI, such as only based on the thin cerebral cortex sheet without subcortical regions? I have such a ROI of course, but I don't know how one could apply GSR in AFNI proc not based on all brain voxels, but only based on the global signal from a specific ROI.

Thanks,
Philipp



Edited 1 time(s). Last edit at 05/23/2023 11:56AM by Philipp.