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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Gang Chen
May 31, 2006 02:37PM
> I get my coefficient values from the regressor I'm interested in
> for Group analysis, aren't the coeffcient values already in percent
> signal change since I normalized the time series in each voxel before
> running 3dDeconvolve?

Yes, they should be if each run of data was scaled properly and separately before running 3dDeconvolve. One way to check is whether the baseline constant of each run is around 100 or 1 (depending on the scaling).

> I spatially blurred my time series during the pre-processing
> stage. Once I convert the coefficient maps from 3dDeconvolve and
> warp them into Talairach space,is it a good idea to do another
> spatial blur for group analysis before using 3dttest or 3dANOVA? Or
> would that just be redundant?

Yes, you can further smooth the percent signal changes out of 3dDeconvolve as much as you like, but keep in mind that spatial filtering increases SNR and normality of the data at the cost of reduced spatial resolution and specificity.

Gang
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Subject Author Posted

Question about Group Analysis

Michael May 26, 2006 03:31PM

Re: Question about Group Analysis

Gang Chen May 26, 2006 04:30PM

Re: Question about Group Analysis

Michael May 26, 2006 04:36PM

Re: Question about Group Analysis

Michael May 31, 2006 01:19PM

Re: Question about Group Analysis

Gang Chen May 31, 2006 02:37PM

Re: Question about Group Analysis

Michael May 31, 2006 02:52PM