Dear Hamed,
The ReML estimation takes place session by session, see
spm_est_non_sphericity.m.
The choice of covariance components, AR(1) or FAST, is unrelated to
having multiple sessions or not.
Best regards,
Guillaume.
On 11/11/16 14:44, hamed nili wrote:
> Dear SPM experts,
>
> I am writing to ask about the GLS implementation in SPM. So as far as I
> know SPM uses restricted ML to obtain an estimate of the covariance
> matrix (required for the GLS solution).
> So when entering multiple runs, how does SPM compute the covariance matrix?
>
> Intuitively, I think it is wrong to do the same as it does for one run
> via concatenating the raw time series and a modified design matrix.
> I am also curious whether FAST would be a better choice than AR(1) for
> the serial correlations in this specific case.
>
> thanks,
> Hamed
--
Guillaume Flandin, PhD
Wellcome Trust Centre for Neuroimaging
University College London
12 Queen Square
London WC1N 3BG
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