[Eeglablist] Channel order after interpolation

[Makoto Miyakoshi]

Dear Shingo,

If you create STUDY using ICs, difference in the number of channels across
subject does not matter. Generally speaking, I would be nervous if I need
to edit channels after ICA since I've experienced some troubles. If you
want to run ICA with interpolated channels, you need to estimate data rank
(by running Matlab function 'rank' note that if you provide too long data
it'll return very low rank!) and use option 'pca' to reduce rank. Thus I
usually recommend one does not interpolate channels after rejecting bad
ones.

> The topography seems different between before and after the re-location
of the channels.

I believe it's just interpolation algorithm returns the different
coordinates than the original coordinates (which were digitized)... if
that's the case it's normal.

Makoto

ps Hirokazu Tanaka who has been with us in SCCN told me that he met you in
ASCON.

On Mon, Nov 23, 2015 at 4:36 AM, Shingo Tokimoto <tokimoto at mejiro.ac.jp>
wrote:

> Dear EEGLAB users,
>
> I am analyzing my EEG data following Makoto's preprocessing pipeline. For
> some of my participants' data, I remove bad channels and interpolate them
> after ICA. When I present the ERP and the ERSP, a warning message appeared
> noticing that the channel locations were different among the participants.
> Therefore, I now re-locate the channels so that the numbers of the channels
> will be identical with that before the channel removal. The topography
> seems different between before and after the re-location of the channels. I
> am wondering whether I should re-locate the channels after the
> interpolation. I appreciate any comments and suggestions. Thank you in
> advance.
>
> ************************************************
> Shingo Tokimoto, Ph.D.
> in Linguistics and Psychology
> Department of Foreign Languages
> Mejiro University
> 4-31-1, Naka-Ochiai, Shinjuku, Tokyo,
> 161-8539, Japan
> tokimoto at mejiro.ac.jp
> ************************************************
>
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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