Problem to configurate electrode positions for freqstatistic analysis

Eric Maris maris at NICI.RU.NL
Fri Mar 23 13:59:05 CET 2007

Hi Conrado,

> I am currently analyzing some old EEG data., butI have some problems
> to define the electrode configuration to run clusterrandanalysis or
> freqstatistics. All data were register in a Neuroscan equipment with a
> strange configuration of 80 channels that is not easy to find in the
> internet or in the Neuroscan website. However, using the script
> prepare_layout, I could get a .lay file with the positions, that is
> very useful to make topographies, but I am not able to use this file
> to define electrode position for statistical analysis. My question is:
> Is there any way to obtain a cfg.elec configuration starting from the
> .lay file so i could use with freqstatistics?

I think not, because the .lay file contains coordinates in a plane, whereas
the cfg.elec structure must contain coordinates in 3 dimensions.

You can construct the neighborhood-structure manually. This is described in
the help documentation of clusterrandanalysis (and in one of the
subfunctions that is called by freqstatistics). This is a boring job and
takes a couple of hours, but it may well be the most time-efficient

Good luck,

Eric Maris

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