Dear SPM users,
I have a question about PPI analysis.
I used parametric effects as input variables when perform PPI analysis.
Q1) Is it possible to use parametric effect to perform PPI analysis?
I'm confused because I knew that PPI is based on Interaction term.
Therefore, I'm wonder that parametric effect also can play a role as psychological variable.
Q2) If it is possible to use parametric effect to PPI analaysis, how do I manipulate input variables and contrast?
In the previous parametric analysis, two parametric regressors(A,B) were analysed.
Now I'm interested in the PPI result with parametric effect A.
This is the part of batch code
jobs{1}.spm.stats.ppi.spmmat = cellstr(fullfile(pwd,'SPM.mat'));
jobs{1}.spm.stats.ppi.type.ppi.voi = cellstr(fullfile(pwd,VOI_Session));
jobs{1}.spm.stats.ppi.type.ppi.u = [1 2 1];
jobs{1}.spm.stats.ppi.name = VOI_Session;
jobs{1}.spm.stats.ppi.disp = 1;
spm_jobman('run',jobs);
I want to know that the third line's code is correct.
The first column of the matrix [1] represent parametric effect 'A' which I'm interested in.
I'm not sure about the second column of the matrix [2].
Also, I omitted the another parametric effect 'B'.
Is it correct?
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