Hard to say. Mostly, it does not make much of a difference, especially if you have a block design. In theory, you could see which one has the lowest residual error, but in general I would not agonize over it.Hi Freesurfers
I have a few questions about gammafit flag in mkanalysis-sess command and I appreciate if you could respond whenever you had time.
-How should we decide which function is best to apply on hemodynamic response signal? I have used both spmhrf and gammafit and I see slightly different results.
No, you have to supply one. I usually use --spmhrf 0-Does Freesurfer has a default function that applies on hemodynamic response signal if I don't use these flags?
We always used delta=2.5 and tau=1.25. These are from Dale and Buckner, HBM 1997, Selective Averaging of Rapidly Presented Individual Trials Using fMRI-Where should I get gfdelta and gftau from?
Thanks
Mona
Zahra (Mona) Nasiriavanaki
Postdoctoral Research Fellow
Martinos Center for Biomedical Imaging
Massachusetts General Hospital
149 13th Street, 149-2615
Charlestown, MA, USA, 02129
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