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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February 25, 2003 11:00AM
Hmmm.
Well, you answered some of my questions and raised some new ones.

First, I should tell you a bit more about my experimental design. I have 10 subjects who each do 3 different tasks within each scan (block design). In my deconvolution, I have each of the 3 tasks plus the 6 motion parameters as regressors (no lags yet). I also have a glt for each pair-wise combination of tasks. When I did 3dttest, I was intersted first in just creating one group map for each of the 3 comparisons, so I used the regression coefficient for condition 1 as -set2 in 3dtest, and either 0 or the baseline map as -set1 (both gave wierd maps).

So, based on your answer, my new questions are:
1. My understanding of 3dANOVA was that it was for inter-group analyses, but I believe you are suggesting that I use it instead of 3dttest for intra-group analysis, is that correct? (Stats has never been my strong suit, so please excuse my ignorance.)

2. You suggested using condition 1 as -set1 and condition 2 as -set2 in order to see the difference between these 2 conditions. How is that different than using the results of the glt for these 2 conditions? (is one better than the other?).

3. You suggest using 3dcalc to create a conjunction map. Although the resulting mask will show the regions of activation within the group, how do I then determine group statistics for the ROIs? (p-values and percent change?). Is this the only way to create group maps for each condition?

4. You suggest "creating a glt to calculate area under the IRF for each regressor". How do I do this? (0 0 1 0 0 0 0 0 0 0 0 ?) How is this different than the regression coefficient that is automatically generated for each regressor?

Thanks!!
Sara

Subject Author Posted

3dttest

Sara February 21, 2003 03:09PM

Re: 3dttest

Christine Smith February 21, 2003 05:29PM

Re: 3dttest

Sara February 25, 2003 11:00AM

Re: 3dttest

Christine Smith February 26, 2003 03:57PM

Re: 3dttest

Sara March 04, 2003 12:54PM