[Eeglablist] ICA preprocessing and bipolar montage configuration

[Scott Makeig]

Velu -

ICA is a linear decomposition, so should be able to decompose bipolar and
common-reference channels in the same session together. However, the
bipolar channels will be 'floating' with respect to the common-reference
channels.  This might interfere with the decomposition (I have no practical
experience here) - but even if not it will mean that the ICA scalp maps
should not be plotted to include the bipolar channels. Here I imagine you
might try to find fixed offsets representing a 'standing difference'
between each bipolar channel and the common reference channel that would
produce max smooth  IC maps -- but are these differences reliably
stationary? I'd be interested to see a result of attempting this ...

Scott Makeig

On Wed, Jun 1, 2022 at 11:42 AM Velu Prabhakar Kumaravel <
velu.kumaravel at unitn.it> wrote:

> Dear EEGLABers,
>
> Does anyone know the effects of ICA preprocessing on EEG acquired using
> bipolar configuration?
> I tried on a few datasets and it looks like the decomposition is not
> effective. Classifying using ICLabel results in more number of "Other"
> category.
>
> Could someone provide insights on this?
>
> Best regards,
>
> Velu Prabhakar Kumaravel, Ph.D. Student
> Center for Mind/Brain Sciences,
> University of Trento, Italy
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-- 
Scott Makeig, Research Scientist and Director, Swartz Center for
Computational Neuroscience, Institute for Neural Computation, University of
California San Diego, La Jolla CA 92093-0559, http://sccn.ucsd.edu/~scott