Make ROIs and select top n voxels

AFNI Message Board
1

Hi all,

I’m a new with afni and making MT Roi for mvpa. I got contrast map with functional localizer and afni’s 3dclust (in GUI) clusterized MT and V1 together in each hemisphere.

  1. I want to use just MT not V1 but I think it requires another way to separation over adjusting threshold. How can I do this? Appreciate if you instruct also how I can merge two MT in each hemisphere in one mask.

  2. After this, I’m planning to select top n voxels in that ROI for further analysis. I searched it and I think 3dcalc and 3drank are used. Can I know how the precess is?

Thanks,

2

See these previous posts for various ways to do this:

https://afni.nimh.nih.gov/afni/community/board/read.php?1,154669,154682#msg-154682
https://afni.nimh.nih.gov/afni/community/board/read.php?1,81039
https://afni.nimh.nih.gov/afni/community/board/read.php?1,74608,74617
https://afni.nimh.nih.gov/afni/community/board/read.php?1,77586,77717#msg-77717

3

Thank you so much! I’ve looked at some of your recommendation but I’ll look into them more. Thank you.