[Eeglablist] how to add markers in continuous EEG data

[Cedric Cannard]

Dear Humera,

Do you have the exact time stamps for your markers (either in seconds, millisecond, or samples). EEGLAB stores markers in the EEG.event structure. Latencies must be in samples (so if you have them seconds, multiply by your sample rate). 

You can simply add them like this:

EEG.event(1).type = 'condition_1';
EEG.event(1).latency = 553;
EEG.event(2).type = 'condition_2';
EEG.event(2).latency = 2437;
etc....
EEG = eeg_checkset(EEG); % to check that formating is correct, will fix inconsistencies or send error if something is not right.

Hope this helps. 

Cedric


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------- Original Message -------
On Tuesday, June 20th, 2023 at 5:57 PM, Lue, James C. via eeglablist <eeglablist at sccn.ucsd.edu> wrote:


> Hi Humera,
> 
> I think the way that event markers are associated with EEG data will vary depending on the type of system one uses. My lab uses EGI Geodesic sensor nets. Net Station produces a .mff file, which is like a .zip file. Inside, in addition to the recording, is an .xml file for user-initiated event markers.
> 
> There were times I had to edit this file to add event markers that were inadvertently missed during the session. Having said that, I've never actually created one from scratch in the case where no event markers were pressed at all. You might want to look at one of your older recordings that have event markers to get an idea of how the event file is formatted.
> 
> James Lue
> ________________________________
> From: eeglablist eeglablist-bounces at sccn.ucsd.edu on behalf of Humera Sharif via eeglablist eeglablist at sccn.ucsd.edu
> 
> Sent: Saturday, June 17, 2023 6:19 AM
> To: eeglablist at sccn.ucsd.edu eeglablist at sccn.ucsd.edu
> 
> Subject: [Eeglablist] how to add markers in continuous EEG data
> 
> Hi,
> 
> I have collected continuous EEG data. For some reason, I could not add
> stimulus markers to it. Could anyone help me how to add markers afterwards
> in my data?
> 
> Thanks in advance!
> 
> Best regards
> Humera Sharif
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