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help > RE: Performing gPPI on a subset of sessions/runs
May 29, 2014 05:05 PM | Christian Utzerath
RE: Performing gPPI on a subset of sessions/runs
Thank you for the information. It is indeed tricky to adress
specific conditions.
I solved the problem by modifying one of the PPPI scripts to accept custom vectors. In the file spm_contrasts_PPI.m, I expanded the 'Compute contrasts' section of the script to accept a user-generated input for the variables xCon and SPM.xCon. This way, sessions can be 'ignored'. However, one should remember that the contrast weights within the vector are usually scaled by the number of sessions (i.e., the weights for an experiment with 9 sessions will be 1/9=0.1111), so that scaling should also be applied onto the user-generated vectors.
Thank you very much!
I solved the problem by modifying one of the PPPI scripts to accept custom vectors. In the file spm_contrasts_PPI.m, I expanded the 'Compute contrasts' section of the script to accept a user-generated input for the variables xCon and SPM.xCon. This way, sessions can be 'ignored'. However, one should remember that the contrast weights within the vector are usually scaled by the number of sessions (i.e., the weights for an experiment with 9 sessions will be 1/9=0.1111), so that scaling should also be applied onto the user-generated vectors.
Thank you very much!
Threaded View
Title | Author | Date |
---|---|---|
Christian Utzerath | May 15, 2014 | |
Donald McLaren | May 16, 2014 | |
Christian Utzerath | May 29, 2014 | |