[FieldTrip] Trigger channel for edf

Robert Oostenveld r.oostenveld at donders.ru.nl
Sun Mar 20 14:41:41 CET 2011

Hi Ivano

Good that it works.

The EDF format is written in blocks. Depending on the software that wrote the EDF file, those blocks might represent experimental trials or might represent subsequent segments from a continuous data stream (which usually contains triggers to indicate the timing of stimuli and responses). 

FieldTrip by default represents each EDF datablock as a trial, and that is reflected in the events (from ft_read_event). With the option cfg.continuous=yes you can tell fieldtrip that it is a continuous recording and that it should not care about the blocks. And you can indeed safely ignore the events of type 'trial' in the event structure.


On 20 Mar 2011, at 13:24, Ivano Triggiani wrote:

> Hi,
> just wanna tell you that changing MATLAB version now everything works!!! Actually I'm using a 2010 version (own by a friend of mine) and everything seems to work.
> However it coul be useful for other users to know that reading edf files, fieldtrip uses a particular field of the edf header called "number of data records" ( http://www.edfplus.info/specs/edf.html ) and another called " duration of data records" that not correspond (at least for my files...) at real number of events occurred. So in my trigger function I have to ignore those informations (or change header of my file!)
> Thanks to all.
> Ivano
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