FSL -
Each subject has 12 EVs. For two subjects, one of their EVs has all 0s in the third column. Thus the main effect maps are blank and I've removed these subjects from group level analyses. The third column values are parametric modulators with expected value or prediction error rather than indication that a certain event occurred.
1) Is there an appropriate way to address this so that I do not have to exclude these subjects? (i.e. add 1 to every single value for every regressor in the third column; alternatively, put .001 in just one element in the 0 regressor)
2) As mentioned I am using values derived from a standard TDRL model. As I understand it, in SPM the parametric modulator looks at variance above and beyond the main effect. Am I doing the same thing in FSL by putting the expected value and/or prediction error in the third column of the regressors?
3) If not, is there a way to do this type of analysis in FSL?
Cheers,
Edward
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