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help > RE: How to denoise with global correlation
May 8, 2018 01:05 PM | Ines Del Cerro - IDIBELL - Bellvitge Biomedical Research Institute
RE: How to denoise with global correlation
Dear Stephen, Dear experts,
Thank you for sharing your method. I am at the same point as you was.
Did you finally find a solution for this problem? I have been doing some tests using QA_GCOR variable and another 'site' variable (is a categorical with 3 levels; 3 different scanner sites) as regressors in 2nd level.
I get the same results when I compare a model with 'site' regressor, and with 'site' + QA_GCOR variables. But they are a little bit differents when I only introduce QA_GCOR as regressor.
My question is if you think I could be over-correcting using 'site' + QA_GCOR? Do you know a better way to do it?
Thank you in advance!
Best,
Ines
Originally posted by Stephen L.:
Thank you for sharing your method. I am at the same point as you was.
Did you finally find a solution for this problem? I have been doing some tests using QA_GCOR variable and another 'site' variable (is a categorical with 3 levels; 3 different scanner sites) as regressors in 2nd level.
I get the same results when I compare a model with 'site' regressor, and with 'site' + QA_GCOR variables. But they are a little bit differents when I only introduce QA_GCOR as regressor.
My question is if you think I could be over-correcting using 'site' + QA_GCOR? Do you know a better way to do it?
Thank you in advance!
Best,
Ines
Originally posted by Stephen L.:
I think I've found how to do it:
* Do your CONN processing as usual, you need CONN >= 17f.
* At 2nd-level analysis, you should see a QA_GCOR_[session] variable. You can select it and regress it out, just like any other.
* I also added a "multicentric" 2nd-level covariate to model which subject belonged to which center.
I tried to regress both QA_GCOR and multicentric covariates, and I did a sanity check on controls from 2 different centers (with 2 different but close TR: 2.0 and 2.46). There were major differences, like more than between the patients vs controls!
Is there anything else that can be done to adjust for multicentric analysis in CONN? Thanks a lot in advance!
* Do your CONN processing as usual, you need CONN >= 17f.
* At 2nd-level analysis, you should see a QA_GCOR_[session] variable. You can select it and regress it out, just like any other.
* I also added a "multicentric" 2nd-level covariate to model which subject belonged to which center.
I tried to regress both QA_GCOR and multicentric covariates, and I did a sanity check on controls from 2 different centers (with 2 different but close TR: 2.0 and 2.46). There were major differences, like more than between the patients vs controls!
Is there anything else that can be done to adjust for multicentric analysis in CONN? Thanks a lot in advance!
Threaded View
| Title | Author | Date |
|---|---|---|
| Stephen L. | Jun 22, 2017 | |
| Stephen L. | Nov 19, 2017 | |
| Ines Del Cerro | May 8, 2018 | |
| Stephen L. | May 9, 2018 | |
| Ines Del Cerro | May 10, 2018 | |
| Jeff Browndyke | Jun 28, 2017 | |
| Stephen L. | Nov 16, 2017 | |