Dear Alfonso and CONN users,

I have not had much luck finding detailed information on the ROI-extraction options in CONN. I am working with several spherical ROIs defined from MNI coordinates, including cortical, cingulate, and parahippocampal regions.

In particular, I am curious about how CONN handles potential white-matter inclusion within these seed regions. 

1. What exactly does the option “Compute weighted sum BOLD signal within each region” do? Under what circumstances is it recommended? What are the weights based on - do they somehow relate to segmentation?
   
2. Similarly, should I enable the “mask with grey matter” option, and in what situations is this advisable?
   
3. I am also uncertain about the appropriate radius for spherical ROIs. CONN’s default is 10 mm, but many papers use values between 4-6 mm. Larger spheres include more WM and adjacent structures, which is my concern. 
   
4. Additionally, does the choice of ROI radius depend on the smoothing kernel or voxel size?
   

Thank you in advance for any help.
Best regards,
Anna