[FieldTrip] question for using ft_timelockgrandaverage

[Constantino Méndez Bértolo]

Dear Anne,

I think ft_timelockgrandaverage expects your individual average (iavg) data
structures to have equal label fields. I know that trying to "grandaverage"
iavgs with different channel labels led to grand averages data structures
with empty-matrix as values. If fieldtrip find labels common to all the
iavg data structures they will be averaged. They are averaged on a "label"
name basis, not on an ordinal basis. If you set cfg.channel to, say 1:3,
and the first three channels of all your iavg datas do not have exactly the
same label names it will return an empty matrix or throw an error. Hence,
if you want to grand average iavgs with different channel labels, you need
to previously manually change the labels so they are the same (maybe there
is a more elegant solution than this workaround).

I hope it was helpful, and correct, otherwise, I wish I will be corrected;
Always give it a try first. It may work, it may throw an error, but
understanding it you will be nearer to the solution


2013/10/22 van Hoogmoed, Anne H - (annevanhoogmoed) <
annevanhoogmoed at email.arizona.edu>

>  Dear all,****
>
> ** **
>
> I’m using ft_timelockgrandaverage to make a grand average of my ERP data.
> However, the order of the channels is different for some people I want to
> include in the average. Does ft_timelockgrandaverage take this into account
> (i.e. does it average on channel name or on channel order)? Or do the
> channels need to be ordered the same for each participant. And if so, how
> should I do this?****
>
> ** **
>
> Thanks for your help,****
>
> ** **
>
> Anne****
>
> ** **
>
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> fieldtrip at donders.ru.nl
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>



-- 
Constantino Méndez-Bértolo
Laboratorio de Neurociencia Clínica, Centro de Tecnología Biomédica (CTB)

Parque Científico y Tecnológico de la UPM, Campus de Montegancedo

28223 Pozuelo de Alarcón, Madrid, SPAIN
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