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  

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Oori
April 05, 2009 11:02AM
Dear AFNI developers,

Is there currently an option for weighting group-level RFX analysis by some "quality" measure derived from the intra-subject level?

I'm referring to measures indexing intra-subject variability in a particular experimental condition (weighting a condition's Beta as function of subject-specific variance; FSL) or perhaps weighting Betas as function of tSNR in the functional run from which they are derived.

I repeatedly see particular brain areas associated with extremely high Betas that also have enormous variances associated with them on the intra-subject level. These betas are not trustworthy, but I currently have no systematic way of down-weighting these on the group level when using AFNI. In various AFNI docs I see that individual level variance is not propagated to the group analysis since “inter-subject variance is much larger than intra-subject variance” – couldn’t it be that in at least a few regions, inter-subject variance is large just because we propagate “nonsensical” betas to the group level?

Cheers,
Oori
Subject Author Posted

inter-subject error in group level rfx

Oori April 05, 2009 11:02AM

Re: inter-subject error in group level rfx

bob cox April 05, 2009 03:17PM

Re: inter-subject error in group level rfx

Oori April 06, 2009 01:24AM

Re: inter-subject error in group level rfx

Gang Chen April 07, 2009 02:05PM

Re: inter-subject error in group level rfx

Oori April 09, 2009 09:16AM

Re: inter-subject error in group level rfx

Gang Chen April 09, 2009 11:45AM