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Bug 1867 - enhancement to reading events from neuromag data

Reported 2012-12-03 15:24:00 +0100
Modified 2014-05-14 20:08:52 +0200
Product: FieldTrip
Component: fileio
Version: unspecified
Hardware: All
Operating System: All
Importance: P3 enhancement
Assigned to: Robert Oostenveld
Depends on:
Blocks: 2489
See also:

Thomas Hartmann - 2012-12-03 15:24:19 +0100

the neuromag system has two different types of trigger channels: a number of analogue channels, each representing one ttl-pulse-line and one digital trigger channel, representing the binary combination of these analogue channels. the combination is done within the elekta neuromag software. we have been experiencing the problem that if trigger lines were not set at exactly the same time, the flanks might be on different samples in the analogue channels. the digital channel represents this then as two different triggers. the attached patch to ft_read_event adds a new version of the reading routine for elekta/neuromag events. it uses the analogue channels to build a new trigger type called "Trigger". the important advantage of the new version is that it has a 'tolerance' option that specifies, how tolerant the building algorithm should be. in order to be used, eventformat has to be set to 'neuromag_fif_v2' i hope it is usefull.

Thomas Hartmann - 2012-12-03 15:25:01 +0100

Created attachment 387 patch for ft_read_event

Juan Vidal - 2013-07-05 14:01:24 +0200

Hi, has this update been integrated into FT? I could use it right now, i need to analyze some neuromag data :-) Best, Juan

Jan-Mathijs Schoffelen - 2014-03-06 15:55:05 +0100

may be related to 2489. Stephen, you may want to look into this.

Thomas Hartmann - 2014-03-06 15:58:20 +0100

(In reply to Jan-Mathijs Schoffelen from comment #3) well, it's only related in the sense that my patch relies on the correct identification of these chantypes.... but i am glad that it reappeared on your radar....

Stephen Whitmarsh - 2014-03-31 12:40:41 +0200

(In reply to Thomas Hartmann from comment #1) Hi there, Thanks for the patch Thomas. I was wondering in what cases you experienced this problem, and using what hardware/software? Although we have not had this problem yet, it would be good to know in what kind of setup this could occur. I'm new with this .diff patch. How should I use it? Cheers, Stephen

Robert Oostenveld - 2014-04-26 20:02:19 +0200

I downloaded the patch from as txt file and applied it to the master svn copy. roboos@mac011> patch -p1 < 36.diff patching file fileio/ft_read_event.m I reviewed the code, and consider it to be a fine change. roboos@mac011> svn commit fileio/ft_read_event.m Sending fileio/ft_read_event.m Transmitting file data . Committed revision 9457. @Thomas, could you comment on the original patch from Dec 2012 (attached in bugzilla) still being relevant?

Thomas Hartmann - 2014-04-27 12:53:24 +0200

(In reply to Robert Oostenveld from comment #6) hi robert, this is great news. thanks for pulling and merging. the pull request superseded the old diff in this bug. the issue can be closed. best, thomas

Robert Oostenveld - 2014-05-14 20:08:52 +0200

closed several of my bugs that have been resolved