triggers and BioSemi

[christophe]

Hi everybody

I'm a new Cartool user and i record visual ERP with BioSemi
As you know triggers are already included in Biosemi output file,
but in my experiment, i have only one type of trigger for many
conditions
so i have another file which tell me which trial match whit what
condition
In order to replace triggers contained in the *.bdf file, I've created
a trigger validation file (.tva) with a trigger code for each
condition, but when i want to average the ERPs for each condition,
Cartool compare the trigger code I've created with the trigger
contained in the Biosemi file instead of replacing it, so all trials
are rejected
I don't know how can it be done...

thanks for your help

[Denis]

On Dec 9, 5:36 pm, christophe <magg_ch...@hotmail.fr> wrote:
> Hi everybody
>
> I'm a new Cartool user and i record  visual ERP with BioSemi
> As you know triggers are already included in Biosemi output file,
>  but in my experiment, i have only one type of trigger for many
> conditions

(not the best way actually, sorry)

> so i have another file which tell me which trial match whit what
> condition
> In order to replace triggers contained in the *.bdf file, I've created
> a trigger validation file (.tva) with a trigger code for each
> condition, but when i want to average the ERPs for each condition,
> Cartool compare the trigger code I've created with the trigger
> contained in the Biosemi file instead of replacing it, so all trials
> are rejected
> I don't know how can it be done...
>
> thanks for your help

You'd rather play with marker file .mrk rather than the .tva file:
- duplicate your triggers into markers (menu Markers)
- edit the new file "youreegfile.mrk" (text file) with whatever you
fancy (Excel, Notepad++, Python, Matlab...) and update the third field
of each line with the actual trigger name. Keep the double quotes, but
feel free to set to any (not too long) text.
- reopen your eeg filen, and check/see your new markers are correct.
- average your eeg file, being careful on the frst dialog to select
Markers and deselect Triggers for averaging.

The second step is of course the sensitive one. Should you miss one
trigger code, and you're experiment is gone without a way to know what
is the problem!

See also:

http://brainmapping.unige.ch/cartool/refguide/eeg.htm#menu%20markers
http://brainmapping.unige.ch/cartool/refguide/files%20formats.htm#mrk
http://brainmapping.unige.ch/cartool/refguide/terms.htm#trigger

Denis

[NicoB]

Hi

which kind of software do you use for the presentation of your
experiement?

Nicolas

[christophe]

thanks a lot Denis
Actually i've found exactly the same method so i'm happy to see i
understand better Cartool

so i import my new marker file on the EEG file, there are all good
(i've tried "import a new marker file" and set "Set Current file for
markers")
but when i want to average my ERPs and that I select only markers for
the averaging
it seems that Cartool don't take into account the new markers I've
imported as if the new marker file and the old bdf files weren't
linked together
Or during the averaging, Cartool tell me it can't write the file and
tell me to indicate a new path file

Excuse me for these numerous questions, I'm a big beginner in Cartool,
I continue to look for a solution on my side
and thanks for the advices

[christophe]

actually it's a program a colleague have created, i don't know how it
works very well

[Denis]

Nice to hear you're getting a grasp on Cartool! :-)

Actually, the way you're importing is correct, but it doesn't set up
things for the next re-opening. To open correctly all your markers
next time, the marker file name has to be "exactly the eeg file name
and its extension.mrk", like "Subject 1 block 1.bdf.mrk". So, just re-
use the file the "Duplicate into Markers" has generated and it should
work like a breeze!

[christophe]

thanks a lot Denis
all work perfectly