EEG lab conversion

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polivaoren
Posts: 2
Joined: 14 Jul 2023, 18:10

EEG lab conversion

Post by polivaoren » 14 Jul 2023, 18:16

Hi. I'm getting contradicting results when converting to EEGlab format. When I load the dat file to MatLab with load_bcidat.m function I get a signal with 197720 time points. However, when I convert to EEGlab with pop_loadBCI2000.m I get 209280 time points. What is the meaning of this difference?

mellinger
Posts: 1207
Joined: 12 Feb 2003, 11:06

Re: EEG lab conversion

Post by mellinger » 14 Jul 2023, 18:41

Hi,

welcome to the BCI2000 forum.

pop_loadBCI2000.m actually uses load_bcidat.m internally, so there should be no differences.
If the problem persists, I would appreciate if you sent me an example file for which this happens, as a private message.

Best regards,
Jürgen

polivaoren
Posts: 2
Joined: 14 Jul 2023, 18:10

Re: EEG lab conversion

Post by polivaoren » 14 Jul 2023, 22:19

Found my mistake. It occurred because I uploaded the filename with an event( EEG = pop_loadBCI2000(filename,{'StimulusCode'}); ). But that leads to a follow up issue/question. When I load BCI, I can go to states and find my variables (StimulusCode). But how do I access this variable after I convert to EEGlab (and without changing the number of time points as we discovered here)?

PS I tried to attach to this thread an example dat file, but the system is sending me an error 'Invalid file extension'

mellinger
Posts: 1207
Joined: 12 Feb 2003, 11:06

Re: EEG lab conversion

Post by mellinger » 15 Jul 2023, 15:09

Events are available as EEG.events, but they are present there in "compressed" form, i.e. only changes are recorded.
If you use pop_loadBCI2000.m from inside EEGLAB, state information will be present in the GUI.
If you are not using EEGLAB, I am not sure why you would want to use pop_loadBCI2000.m instead of load_bcidat.

Upload of raw data to this forum is not possible, but you may send me a private email to mellinger@neurotechcenter.org.

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