I am trying to programming fMRI (BOLD) data processing via SPM12 using MATLAB. I have four stimuli that each participant should note and respond according to each stimulus. When I want to set conditions for 1st-Level, in data some runs lack some stimuli (some of the stimuli have not been used). for example, there is no second-stimulus in run-2, but in others have been used.
Now, should I define an empty vector/zero value for "Onsets of the Condition" or in general I should not set a second-stimulus condition for run-2?
Dear Amin,
You may follow https://www.researchgate.net/post/Failed_Model_Estimation---There_is_no_significant_Voxels
https://www.fil.ion.ucl.ac.uk/spm/doc/spm12_manual.pdf
https://www.researchgate.net/post/fMRI_First_level_analysis_in_SPM_do_i_have_to_separate_sessions
Hey Amin, I have the same situation. Did you find a solution? When I give a 0... It sometimes gives me problems for contrasts but sometimes it works. Do you know if you just leave that condition out in one of the sessions if SPM takes that into account for the betas? For example:
session 1: A B C D
session 2: A C D
If you then concatenate sessions, are the first 4 beta regressors still for A B C D but with less data for B?
Hello dear Lennie Dupont
No, but I use the empty array for that instead of zero for onsets and it works.
I do not find any answer from RG users yet, although one of my supervisors said in this situation we assume that we have the same conditions but for onsets, we should set an empty array.
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