No, there is not. optseq assumes you will be doing an FIR analysis (=finite
impulse response = not assuming a shape to the hemodynamic response). In this
analysis, this must be the relationship. If you assume a shape, then this
relationship is not necessary. In your case, you can set the dPSD=1.
On 7/1/2019 7:19 AM, Davide Nardo wrote:
External Email - Use Caution
Dear Prof Greve,
I hope you don’t mind if I ask you a question about OptSeq.
It looks like a constraint in using OptSeq is that any event duration must be
an integer multiple of the dPSD, which in turn needs to be an integer multiple
of the TR, and seemingly there is no exception to this rule.
I am in a situation in which my TR = 2 sec, and my event duration = 3 sec,
therefore I get an error message when running OptSeq.
However, I am puzzled by this, as in my experience with fMRI an event duration
does not necessarily need to be a multiple of the TR…
Is there any way I can circumvent this requirement in OptSeq?
Best.
Davide Nardo
--
Davide Nardo, PhD
MRC Cognition and Brain Sciences Unit
University of Cambridge
15 Chaucer Road
Cambridge, CB2 7EF
davide.na...@mrc-cbu.cam.ac.uk<mailto:davide.na...@mrc-cbu.cam.ac.uk>
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