The PDC formula implelemted in SPM was given to Will Penny by Luiz
Baccala himself while he was visiting here. If I remember correctly it
was an improved formula that he was about to present at a conference
at the time which might explain the difference. We'll look into it and
try to either find a reference or correct the formula if there is
indeed a mistake.
On Tue, Jul 7, 2009 at 5:42 PM, Elisa Visani<[log in to unmask]> wrote:
> Dear SPM group,
> I'm newcomer in SPM world because usually I work on EEG signal.
> Since few months, we've started to co-register EEg and fMRI.
> I'm trying to use the toolbox 'Spectral', but maybe I found an error in
> spm_mar_spectra.m file.
> In the PDC formula a normalization is performed as Baccalà suggest, but the
> term of variance is used only in the denominator and not in numerator.