Dear SPMers
I have a question re. modelling response accuracy in an efMRI design (I’m assuming a
canonical HRF) which differs slightly from a number of related previous posts I can find.
I have conditions A & B, which, in some but not all cases, can be subdivided into correct &
incorrect responses. My question is, it more valid to specify a model with –
(1) Four canonical HRF-convolved regressors for accurate and inaccurate trials in each
condition; or
(2) Two canonically-convolved conditions with two non-convolved ‘accuracy’ regressors?
The former makes more sense to me theoretically but I’d greatly appreciate the
confirmation.
With thanks
Chris
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