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help > RE: including a parametric modulator
Apr 6, 2020 04:04 PM | Katherine Swett - Vanderbilt University
RE: including a parametric modulator
Hi Alfonso!
I hope you have been doing well (and staying healthy!). I am running a parametric modulation analysis in conn, using the recommendations in this thread. I have one question: it seems that in order to enter the first-level covariate files, other users have pulled the SPM.xX.X vector, which I believe is the hrf-convolved covariate. I was wondering whether putting an hrf convolved time series in the set-up is acceptable, or whether this results in two rounds of convolution that might skew the data?
I appreciate your help!
Best,
Katherine Aboud
Originally posted by Alfonso Nieto-Castanon:
I hope you have been doing well (and staying healthy!). I am running a parametric modulation analysis in conn, using the recommendations in this thread. I have one question: it seems that in order to enter the first-level covariate files, other users have pulled the SPM.xX.X vector, which I believe is the hrf-convolved covariate. I was wondering whether putting an hrf convolved time series in the set-up is acceptable, or whether this results in two rounds of convolution that might skew the data?
I appreciate your help!
Best,
Katherine Aboud
Originally posted by Alfonso Nieto-Castanon:
Dear
Ewa,
Yes, in the latest releases of CONN you may actually perform those PPI-style analyses in CONN directly. To do that you would need to create a series of first-level covariate files (.txt or .mat files) containing your modulator variables and enter those as additional first-level covariates in Setup.CovariatesFirstLevel. Then, in the first-level anlaysis tab you may select the analysis type 'other temporal modulation' effects, and select there each of these covariates, and that will perform a PPI analyses looking at the connectivity modulation associated with your time or distance-to-target variables (i.e. those areas where functional connectivity strength covaries with time or distance-to-target). Unfortunately the 'import' functionality will not automatically read the information of your modulatory variables from your SPM.mat files so you would instead need to manually/progammatically create those first-level covariate files for each subject/session (I will try to add the functionality to automatically import into CONN that info from SPM-defined task-modulation variables to the next release).
Best
Alfonso
Originally posted by Ewa Miendlarzewska:
Yes, in the latest releases of CONN you may actually perform those PPI-style analyses in CONN directly. To do that you would need to create a series of first-level covariate files (.txt or .mat files) containing your modulator variables and enter those as additional first-level covariates in Setup.CovariatesFirstLevel. Then, in the first-level anlaysis tab you may select the analysis type 'other temporal modulation' effects, and select there each of these covariates, and that will perform a PPI analyses looking at the connectivity modulation associated with your time or distance-to-target variables (i.e. those areas where functional connectivity strength covaries with time or distance-to-target). Unfortunately the 'import' functionality will not automatically read the information of your modulatory variables from your SPM.mat files so you would instead need to manually/progammatically create those first-level covariate files for each subject/session (I will try to add the functionality to automatically import into CONN that info from SPM-defined task-modulation variables to the next release).
Best
Alfonso
Originally posted by Ewa Miendlarzewska:
Dear Alfonso,
I am uncertain if this comment also applies to v15.a of conn.
I have a 1st level design in SPM with a time modulator (ordinal values 1-n of trials) and a modulator by distance to target (continuous values 0-1).
Unfortunately, they don't show when I load my SPMs to conn. Under covariate, conn recognizes only the motion parameters which it calls "SPM covariates".
Am I doing something wrong?
Thank you for your help.
Best,
E
I am uncertain if this comment also applies to v15.a of conn.
I have a 1st level design in SPM with a time modulator (ordinal values 1-n of trials) and a modulator by distance to target (continuous values 0-1).
Unfortunately, they don't show when I load my SPMs to conn. Under covariate, conn recognizes only the motion parameters which it calls "SPM covariates".
Am I doing something wrong?
Thank you for your help.
Best,
E
Threaded View
| Title | Author | Date |
|---|---|---|
| Richard Morris | Jul 20, 2012 | |
| Alfonso Nieto-Castanon | Jul 20, 2012 | |
| Ewa Miendlarzewska | Oct 12, 2015 | |
| Alfonso Nieto-Castanon | Oct 14, 2015 | |
| Katherine Swett | Apr 6, 2020 | |
| Isabelle Faillenot | Jun 6, 2025 | |
| Tina Tasia | Jun 9, 2021 | |
| Shady El Damaty | Nov 11, 2016 | |
| Alfonso Nieto-Castanon | Nov 12, 2016 | |
| erik wing | Dec 13, 2016 | |
| Alfonso Nieto-Castanon | Dec 14, 2016 | |
| rcooper1 | Sep 12, 2018 | |
| erik wing | Dec 20, 2016 | |
| Michael Jacob | Oct 3, 2017 | |