Dear Karsten, Rik and others,
> No, they don't need to have the same length. You can specify the duration
> of a trial for each trial separately, i.e. entering a vector of durations,
> having the same length as your SOA vector.
>
Rik mentioned in a previous email:
"The scaling of the regressors in SPM depends on the underlying
neural model and basis functions. Your events are always
delta functions; your epoch model can vary, but assuming
you chose a box-car, and assuming you convolved both
with the same HRF, then the parameter estimates will
depend on the relative scaling of the delta functions
and boxcar."
http://www.jiscmail.ac.uk/cgi-bin/wa.exe?A2=ind02&L=spm&D=0&I=-1&P=102757
Does anyone know how a regressor with different durations is scaled? (which
m-file)
Many thanks,
Carsten
--
Carsten Giessing
Institut für Medizin
Arbeitsgruppe Kognitive Neurologie
Forschungszentrum Jülich
Tel. +(0) 2461/612483
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