Dear Justine,
DCM uses a different haemodynamic model than the canonical model in spm_hrf. It based on the balloon model and has parameters which are separately estimated in each region to improve model fit. See spm_fx_fmri and spm_gx_fmri.m for more details. If you'd like any more details, feel free to get in touch with me and I'll pass your query on to the relevant people.
Best,
Peter
-----Original Message-----
From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On Behalf Of Justine Cléry
Sent: 15 April 2015 13:16
To: [log in to unmask]
Subject: [SPM] DCM : parameters for monkey
Hi everyone,
I want to do a DCM analysis on monkey fMRI data to analyse effective connectivity.
The human HRF saved by default in spm8 (file "spm_hrf.m") has been replaced by a monkey HFR (that in particular takes into account the fact that we do not measure BOLD by use a contrast agent to enhance SNR). This new HRF has been renamed as the default, so all is transparent to spm8.
My question is the following: does the DCM procedure make any assumption on the human based HRF, that I should be aware of, or does it only use the parameters defined in the spm_hfr.m file ?
Anybody already tried DCM on monkey fMRI data?
Thank you!
Justine.and
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