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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March 23, 2008 12:00PM
Hi, I have a set of stimuli with concurrent behavioral data on two dimensions, A and B, with a low correlation between the two. I'd like to see the effect of these behavioral measures on the brain data. In the old days of -stim_times, to solve this I'd create 3 regressors, the first one for the mean effects (just 1s at the onset of events); the second one with the normalized ratings for A (zero mean); the third one with the normalized ratings for B (zero mean).

With the -stim_times_AM2 option, I should be able to create just two .1D files: times*A and times*B. 3dDeconvolve should generate two regressors for each, one for the mean effect and one for the behavior-modulated effect. However, since the times are the same for the two .1D files (I have two behavioral measures per stimulus), I get a collinearity error. I THINK that 3dDeconvolve simply ignores one of the collinear regressors, in cases such as this one, but I'd like to make sure that using -GOFORIT is legitimate in this case.
Thanks.
-G
Subject Author Posted

AM and multiple regressors

Giorgio Ganis March 23, 2008 12:00PM

Re: AM and multiple regressors

bob cox March 24, 2008 09:52AM

Re: AM and multiple regressors

Giorgio Ganis March 24, 2008 11:07AM

Re: AM and multiple regressors

Aaron Mattfeld July 28, 2008 06:44PM