[Eeglablist] How can I use 128 Biosemi channel locations in DIPFIT?

[Makoto Miyakoshi]

Dear James,

This is from my experience of collaboration. I was using MNI model.

1. My conclusion is that you must have 10-5 labels to warp electrodes.
I remember I tried to pair the channels that did not have 10-5 labels
but did not work.

2. So what I did was to pick up 5-10 electrodes that had closest
positions to 10-5 and rename their channels with (approximately)
corresponding 10-5 label names. Using those channels, I could warp
electrodes to fit the model.

3. Of course, you can warp your channels manually. I'm not sure about
availability of fiducials now (I knew there were some issues in it,
but it could have been solved by update. If you find problems please
let us know). The only drawback of this manual adjusting is that it
takes time. However, if your channel locations are not measured but
just using MNI 10-5 template AND your head model is standard MNI
template and not subject' MRI, then you can use parameters obtained
from one subjects for all other subjects.

I know this head model setting has many issues, and sometimes
solutions are not pretty straightforward. Sorry about that. We'll
support you so just let us know when you encounter problems.

Makoto


2012/8/13 James Schaeffer <schaefj3 at gmail.com>:
> Dear eeglablist
>
> I am trying to use 128 Biosemi channel locations in DIPFIT, but I am having
> trouble aligning my electrodes to match the DIPFIT head model.  Do the
> biosemi locations correspond with the 10-20 system?  If so, does anyone have
> the 10-20 labels?  If not, how can I work around this?  I have tried
> aligning the fiducials but the channel locations appear far too low on the
> head model and need to be manually moved into place.  If I move all the
> locations up about 60 mm, they look like they are in place.  Has anyone else
> experienced this? Is there a better way to do this?  Any help would be
> greatly appreciated.
>
> Thanks in advance,
> James
>
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-- 
Makoto Miyakoshi
JSPS Postdoctral Fellow for Research Abroad
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego