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I'm trying the EEGLAB and FASTER plugins for MATLAB in order to do some processing for my EEG data,
When trying to load the data file, I'm asked to choose the "channel location file", but I don't have that with my data, I was wondering if I can create it myself? And if so, How?
I know that each channel in my data corresponds to a specific electrode, how can I write that in the location file?
Thank you

epo3
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hussein hammoud
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2 Answers2

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You can do it by file or by code.

By file (I did not test it so it may not work):

  • create a text file with electrode names - one electrode per line, the order should be the same as in your file. Load the file through edit -> channel locations --> read locations (left bottom corner of the gui). Choose your text file and then use "look up locs" button to get corresponding locations on BESA or MNI head model.

By code and gui (should work well):

  • Create a variable with electrode names (have to be correct names in correct order): 

    elec_names = {'Cz', 'O1', 'O2', 'Fp1', 'Fp2'};
[EEG.chanlocs.labels] = deal(elec_names{:});
eeglab redraw;

    Then use the edit -> channel locations --> look up locs option. Later you can type eegh in command window to get the command that would work on your computer.

mmagnuski
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  • Thanks alot that's exaclty what I wanted. I have a question tho, what if the look up locs didn't find all the channel locations? For example I have the 'RS' Channel which doesn't seem to appear anywhere.. – hussein hammoud Jan 21 '15 at 10:09
  • I'm getting this: Channel lookup: no location for SP1, SP2, RS, EMG, ECG, and PHO. Any idea how can I find the locations for these? Thanks alor for everything – hussein hammoud Jan 21 '15 at 10:45
  • You probably would have to search the web a little to find these. But bear in mind that there is no standard location for EMG - it may be on the face, neck, hand, wherever you want it to be. – mmagnuski Jan 22 '15 at 11:18
  • You could also set an approximate location for these elecs (if you know it) and then use dipfit to project all electrodes to BEM or MNI model surface. – mmagnuski Jan 22 '15 at 11:20
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This sounds like you are not really aware of how EEGLAB works.

From the EEGLAB wiki page on the topic of "Channel Location"

To plot EEG scalp maps in either 2-D or 3-D format, or to estimate source locations for data components, an EEGLAB dataset must contain information about the locations of the recording electrodes.

KEY STEP 5: Load the channel locations.

To load or edit channel location information contained in a dataset, select Edit > Channel locations.

Marcus Müller
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    This sounds like you didn't get my question, I'm aware of all of that, but i don't have the channel location file as stated in my question, so I'm trying to work around it and create the file myself. – hussein hammoud Jan 18 '15 at 11:50
  • That's not working around -- that is *doing exactly what has to be done*. I don't understand why you'd downvote my answer. – Marcus Müller Mar 06 '15 at 15:02