[Eeglablist] Importing .bdf channel locations

[Brett Christopher Bays]

Hi Steve,

Thanks very much, renaming the fields of EEG.chanlocs seems to have worked
well with one exception: I don't know what to rename the two mastoids, the
two HEOG channels, and the four VEOG channels or, without renaming them, I
don't know what coordinates to assign them.  I want to run an ICA so that I
can remove eyeblink components but without being able to properly place the
EOGs I'm not sure how I'd find the proper components.  Can you (or anyone
else) suggest the proper way to localize the remaining electrodes?

Best,
Brett

On Sat, Jan 23, 2016 at 7:30 PM, Stephen Politzer-Ahles <
stephen.politzer-ahles at ling-phil.ox.ac.uk> wrote:

> Looking up the channel names from the BESA template requires that you have
> standard 10-20 names (e.g. F7, Cz, etc.). These names are probably set
> somewhere in your Biosemi acquisition setup. For files that you've already
> recorded that have a different naming scheme, you could manually change the
> channel names after loading the data in EEGLAB (using a loop to go through
> each element of EEG.chanlocs and change the name) and then the template
> should work.
>
> Best,
> Steve
>
>
>
> ---
> Stephen Politzer-Ahles
> University of Oxford
> Language and Brain Lab
> Faculty of Linguistics, Phonetics & Philology
> http://users.ox.ac.uk/~cpgl0080/
>
> On Sun, Jan 24, 2016 at 1:24 AM, Brett Christopher Bays <
> brett.bays at email.ucr.edu> wrote:
>
>> Hi all,
>>
>> Relative newbie to EEGLAB here, so I apologize if I'm missing something
>> obvious, but I cannot figure out how to properly assign channel locations
>> to my bdf data in EEGLAB.  I'm using a BioSemi ActiveTwo 64+8 channel setup
>> (2 mastoids, 2 horizontal eog, 2 vertical lower eog, 2 vertical upper eog)
>> and have an .elp file created in EMSE with all of the matched locations for
>> each electrode.  The .bdf file loads into EEGLAB fine, but trying to load
>> the .elp file using the "Read locations" option of Edit->Channel locations
>> produces the following:
>>
>>
>>
>>
>>
>>
>>
>>
>> *TIP: Call this function directy from the prompt, ">>
>> pop_chanedit([]);"     to convert between channel location file
>> formatsreadlocs(): 'polhemus' format assumed from file extensionreadlocs():
>> Could not read Polhemus coords. Trying to read BESA .elp file.readlocs():
>> 'besa' format assumed from file extensionreadlocs() warning: Fewer columns
>> in the input than expected.                    See >> help readlocsBESA
>> format detected ( Theta | Phi )*
>>
>> [then multiple copies of this warning:]
>>
>>
>>
>>
>>
>>
>>
>>
>> *Warning: Out of range or non-integer values truncated during conversion
>> to character. > In convertlocs (line 180)  In convertlocs (line 200)  In
>> readlocs (line 485)  In readlocs (line 396)  In pop_chanedit (line 664)  In
>> inputgui (line 204)  In pop_chanedit (line 350) *
>>
>> [then:]
>>
>>
>>
>>
>>
>>
>> *Warning: coordinate conversion failedReadlocs: BESA spherical coords.
>> converted, now deleting BESA fields          to avoid confusion (these
>> fields can be exported, though)readlocs(): Inserting electrode labels
>> automatically.Warning: coordinate conversion failed>> *
>>
>> If I allow EEGLAB to look up coordinates using its default of "BESA file
>> for 4-shell dipfit spherical model", I get the following error:
>>
>>
>>
>>
>>
>>
>>
>> *readlocs(): 'BESA' format assumed from file extensionBESA header
>> detected, skipping three lines...Readlocs: BESA spherical coords.
>> converted, now deleting BESA fields          to avoid confusion (these
>> fields can be exported, though)Channel lookup: no location for
>> A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,A24,A25,A26,A27,A28,A29,A30,A31,A32,B1,B2,B3,B4,B5,B6,B7,B8,B9,B10,B11,B12,B13,B14,B15,B16,B17,B18,B19,B20,B21,B22,B23,B24,B25,B26,B27,B28,B29,B30,B31,B32,EXG1,EXG2,EXG3,EXG4,EXG5,EXG6,EXG7,EXG8,StatusSend
>> us standard location for your channels at eeglab at sccn.ucsd.edu
>> <eeglab at sccn.ucsd.edu>>> *
>>
>> Can anyone offer any suggestions or tell me if I'm doing something
>> obviously wrong?  I've read through the EEGLAB Tutorial and tried searching
>> through the archives of this mailing list and found what might be similar
>> problems but couldn't find a solution.  Any help is appreciated, thanks!
>>
>> Best,
>> Brett
>>
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>
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