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

History of AFNI updates  

Previous Message Next Message
Message List New Topic Print View
|
Jeremy
January 11, 2005 12:08PM
Hello,
Recently we have started to spatially constrict the data we input into our 3dANOVA2 mixed effect script.
Our original intent was to only include voxels that were significant in our main effect maps (A and B) from a previously run ANOVA so as to avoid subtractions (A - B) that lead to activation that was neither active in main effect A nor B.
What we found was that when we masked out any non-main effect A and B activity in datasets just prior to the ANOVA (%signal change Gaussian blurred data), we received different ANOVA results in each individual voxel. The difference was slight, but counter intuitive as I thought the ANOVA programs in afni processed on a voxel by voxel basis and there was no spatial variance pooling or anything of that sort.
Based on your more in depth understanding of the math behind the 3dANOVA programs is there any reason that spatially constricting input should affect the output?
Thanks so much for your time!
Jeremy
Reply Quote
RSS
Subject Author Posted

ANOVA question

Jeremy January 11, 2005 12:08PM

Re: ANOVA question

Gang Chen January 11, 2005 03:34PM

Re: ANOVA question

Jeremy January 12, 2005 02:12PM

Re: ANOVA question

Gang Chen January 12, 2005 05:17PM