[Eeglablist] Detrending segmented data before ICA

[Makoto Miyakoshi]

Dear Yamil,

> My concrete question is about the usefulness of detrending to improve
data stationarity before ICA

Yes, detrending helps.

The problem arises when you chop up your continuous data into too short
epochs (< 1 sec, for example) and detrend them separately for channels.
This introduces susceptibility to noise fluctuation.

Makoto

On Wed, Oct 21, 2015 at 4:50 AM, Yamil Vidal Dos Santos <
hvidaldossantos at gmail.com> wrote:

> Hi all,
> I have a question regarding getting data ready for ICA.
> As one factor that affects the quality of an ICA decomposition is the
> stationarity of the data, I decided to segment and detrend my data before
> running ICA. But I have read that if one would run ICA on segmented data,
> one should have a long enough baseline and/or should not remove baseline.
> This sounds strange to me, because as far as I know, ICA is not concerned
> about time. Furthermore, data is whitened before running ICA. Doesn't this
> imply a baseline removal?
>
> My concrete question is about the usefulness of detrending to improve data
> stationarity before ICA, but any clarifications about how to improve the
> chances of getting a good ICA decomposition will be appreciated.
> Thanks,
> Yamil
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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