You can also look at:
K.Friston et al. Non-linear event-related responses in fMRI. MRM 39(1):41-52(1998).
>
> While it is similar to that derived empirically by Zarahn and colleagues,
> I think the HRF used in SPM was actually derived by Karl Friston from
> a PCA across activated voxels (activation as determined by a Fourier set)
> from the data described in Josephs et al. (1997), but apologies to anyone
> concerned if my historical understanding is wrong.
>
>
> "Johnson, Sterling - MHA" wrote:
>
> > I believe the shape of the HRF was empirically derived based on the work of
> > Zarahn
> >
> > Zarahn, E., G. Aguirre, and M. D'Esposito, A trial-based experimental design
> > for fMRI. Neuroimage, 1997. 6(2): p. 122-38.
> >
> > Best wishes,
> >
> > Sterling C. Johnson, Ph.D.
> > Neuropsychology
> > Barrow Neurological Institute
> > 222 W. Thomas Rd. Ste 315
> > Phoenix AZ 85013
> > ph: 602-406-3671
> > fx: 602-406-6115
> > email [log in to unmask]
> >
> > > -----Original Message-----
> > > From: Dr Afraim Haddadi [mailto:[log in to unmask]]
> > > Sent: Wednesday, February 07, 2001 11:39 AM
> > > To: [log in to unmask]
> > > Subject: SPM HRF Reference
> > >
> > >
> > > Dear all,
> > >
> > > Can anyone provide me with a literature reference for
> > > the default canonical HRF shape, assumed by spm_hrf?
> > >
> > > Much appreciated,
> > >
> > > Afraim
> > >
> > >
> > > ----------
> > > Dr A Salek-Haddadi
> > > Clinical Research Fellow
> > > Institute of Neurology
> > >
>
> --
> ---------------------------8-{)}-------------------------
>
> DR R HENSON
> Institute of Cognitive Neuroscience &
> Wellcome Department of Cognitive Neurology
> 17 Queen Square
> London, WC1N 3AR
> England
>
> EMAIL: [log in to unmask]
> URL: http://www.fil.ion.ucl.ac.uk/~rhenson
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