[FieldTrip] ancova for sources analysis

["Jörn M. Horschig"]

Dear Gabriel,

if you have a .stat field, you did already run statistics on your data. 
I wouldn't regress anything out of e.g. t-values. Rather, the idea is to 
regress out confounding factors before doing statistics, so that you 
reduce variance across trials and subsequently maximize sensitivity of 
your statistical test. I could really advise you to read the paper I 
suggested, the rationale is explained there.
Moreover, if you are interested in a covariate like 'age', a simple 
correlational analysis might make more sense. As stated, the idea of 
regressconfound is to explain and remove variance across observations, 
but depending on what you want, a correlation might make more sense.
Want to improve your stats? Then go for regressconfound. Find out if 
there is age explains neural effects? Then go for a simple correlation.

Best,
Jörn

On 7/31/2013 11:56 AM, Gabriel Gonzalez Escamilla wrote:
> Thank you all for your responses.
>
> The last problem I did wrote is now solved, see below.
>
> I had a field called 'stat' instead of the 'pow', I'm guessing this 
> field was set before, so, now i'm using this field as if it was the 
> 'pow' I needed and it's working, Is that OK?
>
> Now it takes me to the next question, my data has the avg field, and 
> it says that will update the descriptives but that the 'method' is 
> missing, is this update necessary? or can I just skeep it?
>
>
> Many thanks in advanced,
> Gabriel
>
>
> ----- Mensaje original -----
> De: "Stolk, A." <a.stolk at fcdonders.ru.nl>
> Fecha: Miércoles, 31 de Julio de 2013, 10:04 am
> Asunto: Re: [FieldTrip] ancova for sources analysis
> A: FieldTrip discussion list <fieldtrip at science.ru.nl>
>
> >Dear Gabriel,
> >
> > This page demonstrates how to remove contributions to the data 
> originating from head movement, but one could as well follow the same 
> principle for any other type of covariate (e.g. eye movement related 
> activity).
> >
> > http://fieldtrip.fcdonders.nl/example/how_to_incorporate_head_movements_in_meg_analysis?
> >
> > Yours,
> > Arjen
> >
> ------------------------------------------------------------------------
>
>     *> Van: *"Gabriel Gonzalez Escamilla" <ggonesc at upo.es>
>     *> Aan: *"fieFieldTrip discussion list" <fieldtrip at science.ru.nl>
>     *> Verzonden: *Woensdag 31 juli 2013 09:05:34
>     *> Onderwerp: *[FieldTrip] ancova for sources analysis
>     >
>     > Dear fieldtrip experts,
>     >
>     > I'm wondering if it is possible to perform an ancova or to remove
>     the effect of a covariate in a source analysis?
>     >
>     > Many thanks in advanced,
>     > Gabriel
>     > _______________________________________________
>     > fieldtrip mailing list
>     > fieldtrip at donders.ru.nl
>     > http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
>
>
> > _______________________________________________
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> > http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
>
> <font size="3">--------------------------<br />PhD. student Gabriel 
> González-Escamilla<br />Laboratory of Functional Neuroscience<br 
> />Department of Physiology, Anatomy, and Cell Biology<br />University 
> Pablo de Olavide<br />Ctra. de Utrera, Km.1<br />41013 - Seville<br 
> />- Spain -<br /><br />Email: ggonesc at upo.es<br 
> />http://www.upo.es/neuroaging/es/</font>
>
>
> _______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip


-- 
Jörn M. Horschig
PhD Student
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognitive Neuroimaging
Radboud University Nijmegen
Neuronal Oscillations Group
FieldTrip Development Team

P.O. Box 9101
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The Netherlands

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