[Eeglablist] Processing ICA component activation prior to unmixing

[Evyatar.Arad at sheba.health.gov.il]

Dear Makoto,

Thanks for the reply. While trying to run the line, the following error is generated:

Error using  *
Inner matrix dimensions must agree.

icasphere is of size 30x30
icaweights is of size 24x30. This is due to the removal of 6 components (EOG, EMG etc.).

I could start by modifying the ICA activations before removing any other components, but I'm sure there's a way to perform it in the desired order (artefact removal >>> modifying components and running the aforementioned command).

Best regards,
Evyatar

From: Makoto Miyakoshi [mailto:mmiyakoshi at ucsd.edu]
Sent: יום ו 13 ינואר 2017 06:38
To: ערד אביתר <Evyatar.Arad at sheba.health.gov.il>
Cc: eeglablist at sccn.ucsd.edu
Subject: Re: [Eeglablist] Processing ICA component activation prior to unmixing

Dear Evyatar,

You can hack EEGLAB by saying EEG = NewEEG. But if you do this, beware that EEGLAB always runs a consistency check function, namely eeg_checkset(), so your modified data should be compatible with their check criteria.

By the way, in the eeg_checkset() you can find the line that does the same thing. You may want to check it out just to make sure. I think your code is correct, but I got always confused with the order of this matrix multiplications.

NewEEG = inv(EEG.icasphere * EEG.icaweights)*EEG.ICAact


Makoto

On Mon, Dec 26, 2016 at 12:02 AM, Evyatar.Arad at sheba.health.gov.il<mailto:Evyatar.Arad at sheba.health.gov.il> <Evyatar.Arad at sheba.health.gov.il<mailto:Evyatar.Arad at sheba.health.gov.il>> wrote:
Dear list,

I would like to process some of the ICA activations and then use the modified activations for the channel reconstruction. I suppose


NewEEG = inv(EEG.icasphere * EEG.icaweights)*EEG.ICAact

could be used, but I want the reconstructed dataset to be fully integrated into the EEGlab GUI. I've searched the list archives and haven’t found anything, so help would be much appreciated.

Thanks and good week.
Evyatar Arad
R&D Engineer
Centre of Advanced Technologies in Rehabilitation
Sheba Medical Centre



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--
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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