Hi All,
I've been trying to use the "Confound EV" option to add a bunch of really simple boxcar regressors to my GLM. Basically I want ones for the first N timepoints and zeros for everything else. However, when I enter this type of regressor (using a single column text file) and view the design, I get something that looks strange, almost like the second derivative of my boxcar regressor. In other words at the point when the regressor changes from 1 to 0 I get a spike, but otherwise the regressor looks flat.
Any ideas what might be causing something strange like this?
Thanks,
Sam
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