[Eeglablist] Problem with epoching and boundary events

Philipp Spachtholz Spachtholz at psy.lmu.de
Fri Jan 10 03:20:02 PST 2014


Dear all,

i am new to EEGLAB and started doing some scripting and came across a 
problem. Maybe
someone can help me.

I import data from Brain Vision Analyzer (where i marked bad data 
stretches). I then read out the
datapoints of these bad strechtes using the event "userdefined" and 
subject those values to
eeg_eegrej. This seems to work well and the bad stretches are replaced 
with a boundary event.

However when I do epoching over all stimulus events (each stimulus event 
only occurs once in my experiment), some of them are epoched although 
the interval contains a boundary event.
For example i have a Stimulus type 'S 79' which is followed by a 
boundary event within 1 second. If i specifically select this event for 
epoching with a time range of [-0.6 1.8] i get an error (which makes 
sense to me).
If i select stimulus type 'S 79' and the succeding event after the 
boundary event (or another one), only the event
after the boundary is selected for epoching --> I get 1 epoch.

However when i select more than 2 stimulus types for epoching, e.g. 3 
events then I get 3 epochs,
including the S 79.

Do you have any idea why this might happen?
This happens both using the script and the gui.

thank you very much for your help

Philipp Spachtholz


-- 
Dipl. Psych. Philipp Spachtholz

Department of Psychology
University of Munich
Leopoldstrasse 13
80802 Germany
Phone: +49 (89) 2180-5229
E-Mail: Spachtholz at psy.lmu.de



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