[FieldTrip] global field power

Eelke Spaak eelke.spaak at donders.ru.nl
Thu Nov 8 20:46:34 CET 2012

Dear Nenad,

The only definition I could find for 'global field power' in the
context of EEG is indeed as JM suggested, the standard deviation over
channels. Of course, computing this std collapses across the channel
dimension, so you end up with a dimensionality of 1 where previously
there was the dimensionality of nChannels.

If this is not what you are after, you need to give us a clear
definition of what you mean by 'global field power'.


On 8 November 2012 20:34, Nenad Polomac <polomacnenad at gmail.com> wrote:
> Dear Jan and Elke,
> Thank you for your ansewers!
> I have applied The Matlabs std function on data.avg matrix and it doesn't
> give me good results. Namely, it returns matrix with  [1 x time points] so
> it reduces number of channels to one, which is not what I want. I believe
> this is because the sum function sums data column-wise. My question is could
> I do only sqrt(data.var). Would this result be proper way of calculating
> global field power?
> All the best!
> Nenad
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