[Eeglablist] Defining channels locations for Biosemi data

[Fucci, Enrico]

Dear all,


I hope you will help me elucidating this simple question:


After importing EEG data (64 electrodes cap) from Biosemi format into EEGlab (through Biosig), I procede to define channel coordinates. For this, I tried two different ways, that result in slightly different electrode configurations when plotted on a 2D template.


The first method consists in adding a .loc file where electrode locations are derived from the template "GSN64v2_0.sfp" provided by EEGlab. Regarding the second method, I just automatically retrieve channel locations using the BESA file "standard-10-5-cap385.elp" implemented in dipfit, after having renamed channel labels from Biosemi to 10:20 convention.


Both methods give locations coherent with the Biosemi layout, but slightly different in terms of matching with the 2D template (electrodes defined by BESA trepass the head model border). Does anyone know what is this difference caused by?


You can find the .loc file and the two plots on the 2D template at the following link (do not mind the external electrodes) :


https://www.dropbox.com/sh/56x8z3u8j80lyg9/AAC2lm95zy4eKxOr1kHSByMFa?dl=0



Thank you very much for the support.


Best,


Enrico Fucci

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sccn.ucsd.edu/pipermail/eeglablist/attachments/20161118/d0f7d306/attachment.html>