AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

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Pat Bedard
January 14, 2009 10:36AM
Hello,

So I have 4 conditions (2x2 design) of interest in my experiment. First I averaged the Beta weights of these 4 conditions for each subj and then ran a t-test on these averaged maps to keep only those task-related areas. I then threshold at the voxel (p=0.001) and cluster (n>11 voxels from Alphasim output), and end up with a map of activated areas (mask) of about 10 000 voxels.

Then I use 3dANOVA3 to determine how these 4 conditions modulate the MRI signal in that mask.

My question is what kind of voxel and cluster threshold do I have to implement here. Can I be more liberal on the voxel threshold since I already restricted my search area? Do I have to run alphasim on the mask to determine the number of voxels in a cluster?

Any thoughts is welcome!!

Thanks for you help,
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Subject Author Posted

Statistical threshold

Pat Bedard January 14, 2009 10:36AM

Re: Statistical threshold

Gang Chen January 14, 2009 04:41PM

Re: Statistical threshold

Pat Bedard January 18, 2009 02:05PM

Re: Statistical threshold

Gang Chen January 21, 2009 10:47AM