[Eeglablist] EOG channels included in ICA and DIPFIT

[Tarik S Bel-Bahar]

Hello Alessio,

There is no perfect solution for mixed ICs, and some ICs still get some
artifactual pollution.
There is usually only one eye-blink IC and one lateral-eye-movement IC,
sometimes double that, but that's it, normally.
So getting multiple big ICs that explain a lot of variance and have a lot
of eye-artifact activity suggests the data and/or decompositions may not be
ideal.
It depends on the researchers whether or not those ICs are considered
artifactual or not (the mixed ICs, that is).
You will get ICs corresponding to blinks and lateral eye movement if these
are represented well-enough in the data,
regardless of whether you have EOG channels or not. The important thing is
if there are channels near/above the eyes/forehead, which easily capture
eye-related artifacts. However, including EOG channels might "increase" the
validity of eye-blinks ICs, in some way providing ICA good information.
Note however that ICA focuses mainly (I believe) on spatial patterns across
multiple channels, and not really single channels.
Please see Luca's online ICA classification examples and training tool
mentioned in the eeglablist several times. You might get some ideas from
there.
It's likely that the field will continue to see mixed-ICs for some time
until classification techniques get more robust.

On Sun, Feb 12, 2017 at 4:31 AM, Alessio Matiz <muec at inbox.com> wrote:

> Very dear EEGLAB-list,
>
> is it correct to fit dipoles (via DIPFIT2-plugin) to ICs that have been
> found including EOG channel in the ICA decomposition (as Arno suggested in
> https://sccn.ucsd.edu/pipermail/eeglablist/2007/001801.html)?
>
> From my datasets I removed ICs where EOG channel contributes for >90% of
> IC power (considering them artifactual ICs), but how to deal with ICs where
> EOG contributes for example for 20%, or 40%, or 60%?
>
> Thanks,
> Alessio
>
>
>
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