Hello!
I imported EGI .mff file to Brainstorm and in place of regular triggers (at one timepoint - e.g., 5.00 sec) I have extended triggers (4.00 - 6.00 sec). I can simply transform then into the simple events (Convert to simple event) but then I am asked "What part of the extended events do you want to keep?". Does it mean that I need "Start" function to have a trigger position at the beginning of stimulus?
Thank you!
I'm sorry, I'm not sure I understand your question.
You have an extended event lasting for 2s. You can import them as is into the database (in that case you do not have the option to set an "epoch time"), or you can convert it to a simple event (and them import it with the parameter "epoch time" enabled, as in the introduction tutorials).
In the latter case, you can decide whether your want to keep the first sample, the central sample or the last sample. If the beginning of the stimulus correspond to the first sample of this segment, then select "keep the start of the events" and use the option "epoch time" to define how much data you want in your epochs before and after this sample.
Hi Francois,
Thank you for the replay. I am sorry for the uncertain question, my question was more about the importing .mff file to Brainstorm with correct trigger positions. When I open .mff file in Net Station or EEGLAB, I have regular triggers, but when I open the same file in Brainstorm, triggers are imported only as extended triggers. To convert them to the regular triggers, I used "Events -> Convert to simple events" and it asks "What part of the extended events do you want to keep?". So, it would generate simple events and put a trigger at the beginning / middle / or end of the extended trigger. My question is about where I need to put the simple event (during conversion from extended to simple) to have it at the beginning of the stimulus.
My question is about where I need to put the simple event (during conversion from extended to simple) to have it at the beginning of the stimulus.
I don't know, it depends on your data.
Look at one example where you can identify clear features in the EEG signals, that you can observe both in Brainstorm and in EEGLAB/NetStation.
Can you please share this example file?
(upload it somewhere and post the download link here)
I'd like to check whether there is something wrong with the MFF library.