Dear SPMers,
I have a questions concerning parametric regressors in an event-related fmri working-memory task with three levels of memory load.
In my first level design matrix I have specified one regressor for the working memory load :
WM load 1 -> parametric modulation = 1
WM load 2 -> parametric modulation = 2
WM load 3 -> parametric modulation = 3
Additionally I have a regressor for the baseline condition (fixation cross) and a regressor for the “missed” events.
My questions:
1. Is it reasonable to include the regressors for the baseline condition and the “missed” events in the 1-level designa matrix?
2. Does the does the order in which I specify the regressors in the 1-level design matrix (e.g. baseline / working memory load / missed) matter?
Thanks in advance & best regards
Ben
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