I have a pre-post two session study with six conditions in each session. I tried to run a GLM for each subject by specifying the two sessions in the same model, but having separate names to identify the events in each session ( like ses1condition A, and ses2condition A, etc.) While the design matrix I get looks the way it is supposed to look, the predicted vs observed looks messed up with respect to the event onsets. Could this be because I am specifying the onset vectors in terms of samples and somehow there is a confusion between the two sessions ( I assumed PsPM would be reading the onset files only in relation to the specific session's data file, is this not the case?)
Thanks!
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If the design matrix looks ok in the review model menu, then there is little to worry about in terms of the onsets - this is exactly the same matrix used for model inversion.
It's always a good idea to check predicted vs. observed and reconstructed responses. If there is something wrong, perhaps the timing did not match the experiment stimuli in the first place? In any case, I'm happy to look at it if you post it here or send via email.
Dominik
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi!
I have a pre-post two session study with six conditions in each session. I tried to run a GLM for each subject by specifying the two sessions in the same model, but having separate names to identify the events in each session ( like ses1condition A, and ses2condition A, etc.) While the design matrix I get looks the way it is supposed to look, the predicted vs observed looks messed up with respect to the event onsets. Could this be because I am specifying the onset vectors in terms of samples and somehow there is a confusion between the two sessions ( I assumed PsPM would be reading the onset files only in relation to the specific session's data file, is this not the case?)
Thanks!
Hi.
If the design matrix looks ok in the review model menu, then there is little to worry about in terms of the onsets - this is exactly the same matrix used for model inversion.
It's always a good idea to check predicted vs. observed and reconstructed responses. If there is something wrong, perhaps the timing did not match the experiment stimuli in the first place? In any case, I'm happy to look at it if you post it here or send via email.
Dominik