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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rick reynolds
November 15, 2022 01:43PM
Hello,

From what you are saying the stim-active.txt file should not have those events at time 180 (time 180 should be for passive). As it stands, there are events at 0 and at 180, and each lasts for 180 s, which is the same as a single event that lasts for 360 s.

So stim-active.txt should probably look like: 

0 *
0 *
0 *

Where the '*' characters are to make it look like "local" timing, rather than global. Otherwise, you could put "-local_times" before the -stim_times options. and just have a column of 0's.


Note that the results might be surprisingly noisy. The blocks are very long, so baseline drifts highly correlate with the regressors of interest. Also, the 2 regressors of interest will have correlations close to -1, they are almost negatives of each other (their sum would be practically a flat line). That seems a bit problematic.

- rick
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Design matrix and 3dDeconvolve Attachments

Khazar November 15, 2022 12:03PM

Re: Design matrix and 3dDeconvolve

rick reynolds November 15, 2022 01:43PM