Dear Christian,
Thank you very much for your helpful answer. I never run melodic with command line, do you have any documentation explaining that?
Mohamed
----- Mail original -----
De: "Christian F. Beckmann" <[log in to unmask]>
À: [log in to unmask]
Envoyé: Vendredi 18 Juin 2010 23:37:50
Objet: Re: [FSL] ICA global signal question
Hi
melodic does not remove the mean time course - though you can request
this to happen using the --remove_meantc command line option. I suspect
that what you see is simply due to the fact that melodic by default
performs variance normalisation in order to avoid the tissue-type bias
in the PCA step. Have you run melodic without this (i.e. use --vn) to
see if that explains things?
hth Christian
On 18 Jun 2010, at 08:41, Mohamed Bahri wrote:
> Dear FSL experts,
>
> I performed a single-session ICA both with Melodic FSL and
> BrainVoyager. The visual inspection of the results (Z-map) reveals the
> presence of one component representing a mean signal (global signal).
> This global signal component is present only in the BrainVoyager
> results. So, my question is: does Melodic ICA filter out the global
> signal? if yes, how does it do that?
>
> Any comment will be very welcome,
>
> Many thanks in advance,
>
>
> Mohamed
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