[FieldTrip] EGI 64 - channel locations doesn't work in FTrip

Anna Wieczorek-Taraday anna.wieczorek.taraday at gmail.com
Tue May 12 10:17:40 CEST 2015

Dear Fieldtrippers,

I have a problem while reading EEG (EGI) electrode location file to FieldTrip.
I am using EGI Amp 300, 64-channel cap, data were exported to .raw files.

When I read locations to EEGLAB, it works well  (lilnk to pictures<https://www.dropbox.com/sh/aq4purahda5iq1x/AAABpAqJJTYAXcMgW4FsBDzWa?dl=0> || see pic. eeglab_chanlocs.jpg). The layout corresponds with the actual electrode placement in the cap.
When I read the same file into FieldTrip, the electrodes seem to have similar layout (see pic. fieldtrip_chanlocs.jpg).
However, it seems like the electrodes are confined within the plot too much. Electrodes E61:E64 should be outside of boundaries of the layout plot.

I was wondering whether anybody else had similar issue and did overcome it? Could anybody suggest what is wrong and how can I read the locations properly?
Any support will be appreciated.

I am using Matlab 2015, eeglab eeglab13_4_4b and the latest version of fieldtrip.


Here is code I used to read these locations:

cfg.layout      = 'C:\Users\annwie\Documents\awt_chanlocs\GSN-HydroCel_64.sfp';
cfg.feedback    = 'yes';
layout          = ft_prepare_layout(cfg);

Here is the code that I used to preprocess my data in Fieldtrip:

cfg = [];
cfg.trialfun = 'ft_trialfun_general';
cfg.dataset = '136.set';
cfg.trialdef.eventtype  = 'trigger';
cfg.trialdef.eventvalue = 'DIN8'
cfg.trialdef.prestim    = 0.5;
cfg.trialdef.poststim   = 2.5;
cfg = ft_definetrial(cfg);

cfg.lpfilter = 'no';
cfg.hpfilter = 'yes';
cfg.hpfreq = 0.3;
data = ft_preprocessing(cfg);

Anna Wieczorek-Taraday.

PhD Student
Nencki Institute of Experimental Biology
Pasteur Street 3, 02-093 Warsaw, Poland

Warsaw University of Social Sciences and Humanities
Chodakowska Street 19/31, 03-815 Warsaw, Poland
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