[Eeglablist] Event Markers from multiple channels

[Rinkel, Bridget]

Hi everyone,

I am working to import a .mat EEG data file into matlab with EEGLab using the biosig plug in. I have two main questions:

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What are the options I could put for "event mode import" when importing data with the biosig plug in and what do they mean?
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Is it possible for me to extract event markers from multiple different data channels?

For example, the .mat file I have has 19 total columns. Columns 1:15 are EEG channels, plus 2 EOG, 1 ECG, and one respiration column. Columns 16:19 are the event marker data channels. There are 4 data channels because each of the 4 channels represents a different even type. When events occur, they are marked with a '5' in each of the 4 channels (I need to work on changing the value to a different number for each event type).
To import the data, I use file -> import data -> using EEGLab functions and plugins -> from Biosemi BDF file (BIOSIG toolbox). When doing so, I deselect the 'extract event from marker channel' so that it doesn't assume my last column is my only event marker column. I am not sure what to list for the 'event mode import' but the default is populated with a 4 so I leave that as is. This seems to read in all of my data okay.
To indicate the event channels, I do: File -> import event info -> from data channel. To specify that my event markers are in channels 16-19, In the 'event channel(s)' box, I input '16 17 18 19'. This then deletes these event marker channels from my data, and labels the events. However, when I try checking the labels visually by doing plot -> channel data (scroll), they are all labeled with the same label, as "chan 16 17 18 19". When I go to inspect them further, by doing Edit -> event values, I also see that every single event is labeled as 'chan 16 17 18 19'. In my actual data, in each column, the event markers have a numerical label (5). I must be importing the event markers incorrectly, but I'm not sure where I'm going wrong. How do I get the event labels to be the numerical value that occurs in each data column for each of my four event marker channels, and not 'chan 16 17 18 19'? Is it possible to use event markers from different channels like this?

Thank you,
Bridget