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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September 16, 2019 03:10AM
Hello,
I want to have a map of a contrast between two conditions at the single-subject level. I tried two ways to do that, which resulted in exactly the same thing, which perhaps is good news but this confuses me. I did expect different results.

Option 1: gltsym in 3ddeconvolve
-gltsym 'SYM: +C1 -C2' -glt_label 1 'Contrast_map1' \


Option 2: 3dcalc
(Assuming for the example C1 is sub-brick 2 and C2 is sub-brick 4).
3dcalc 'func+orig[2]' -b 'func+orig[4]' -expr 'a - b' -prefix Contrast_map2

Option 2 is a difference between t-statistics, while Option 1 a t-statistic of a difference.

1. Are they expected to have different outputs? If so - in what way? And what should I use?
2. Does it make sense that the contrast map I get is the same no matter what option I use?
Subject Author Posted

contrast map - gltsym vs. 3dcalc

Galit September 16, 2019 03:10AM

Re: contrast map - gltsym vs. 3dcalc

rick reynolds September 16, 2019 08:56AM

Re: contrast map - gltsym vs. 3dcalc

Galit September 18, 2019 04:59AM

Re: contrast map - gltsym vs. 3dcalc

gang September 18, 2019 02:52PM

Re: contrast map - gltsym vs. 3dcalc

Galit September 19, 2019 06:37AM

Re: contrast map - gltsym vs. 3dcalc

gang September 19, 2019 10:39AM