[Eeglablist] Problem with Channel Locations (Makoto's Preprocessing Pipeline)

[Clement Lee]

Hi Mahjabeen,

When you first import the data into EEGLAB, check channel locations and
click "cancel" instead of "ok" when it asks what templates to use. Likely
the fields will be empty besides the labels - it's possible that EEGLAB
does not import the raw data format properly so the channel information is
lost, or that your manufacturer meant to say "channel labels are already in
the raw data." That means while you do not have to import any files, you
have to look up locations based on a template anyways. Try the MNI template
that is available by default with EEGLAB.

Best,
Clement Lee
Applications Programmer
Swartz Center for Computational Neuroscience
Institute for Neural Computation, UC San Diego
858-822-7535


On Mon, Mar 23, 2020 at 9:07 AM Mahjabeen Rahman <
mahjabeen.rahman at knights.ucf.edu> wrote:

> Hello everyone,
>
> I am a novice EEG researcher and not very good at coding. We are using a
> Cognionics system of 10-10 configuration (64 channels). The device
> manufacturer said,  the channel locations are already in the raw data, so
> no need to import any file.  When I try to select BEM DIPFIT model and opt.
> head center, then I am getting the following:
> I dont know if its something to worry about. Our raw data is in .bdf
> format.
>
> "readlocs(): 'elc' format assumed from file extension
> Reading file (lines): 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
> 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340
> 350 360 370 380 390 400 410 420 430 440 450 460 470 480 490 500 510 520 530
> 540 550 560 570 580 590 600 610 620 630 640 650 660 670 680 690 698
> readlocs(): 'elc' format assumed from file extension
> Reading file (lines): 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
> 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340
> 350 360 370 380 390 400 410 420 430 440 450 460 470 480 490 500 510 520 530
> 540 550 560 570 580 590 600 610 620 630 640 650 660 670 680 690 698
> Radius values: 97.2255 (mean) +/- 11.2354 (std)
> Optimizing center position...
> Wobble too strong ( 12%)! Re-centering data on (1.19058,-16.0254,2.35827)
> Wobble (5.7%) after centering data on (1.19058,-16.0254,2.35827)
> Note: automatically convert XYZ coordinates to spherical and polar
> EEG checkset note for expert users: Noze direction now set to default +X
> in EEG.chanlocs and EEG.dipfit."
>
>  After this message, I  thought I would check if it converted to BEM. So I
> tried edit=>channel locations, it shows coordinates in BESA.   I am really
> stuck here. I think, for this , I am also facing problems in later steps
> (e.g. AMICA,DIPFIT). If anyone with experience helps, I would be grateful.
>
> P.S. If I go with BESA, would that be a problem ?
>
> Thanks in advance,
> Mahjabeen Rahman
> PhD Student
> Industrial Engineering & Management Systems
> University of Central Florida
> _______________________________________________
> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
> To unsubscribe, send an empty email to
> eeglablist-unsubscribe at sccn.ucsd.edu
> For digest mode, send an email with the subject "set digest mime" to
> eeglablist-request at sccn.ucsd.edu
>