[Eeglablist] Recovering single component's channel data manually

Robert Gougelet rgougelet at gmail.com
Wed Aug 7 13:10:46 PDT 2019


I just wanted to verify the following:

EEG.icaact = EEG.icaweights*EEG.data;
EEG.data = EEG.icawinv*EEG.icaact;

When applying an ICA decomposition to a dataset in earlier preprocessing, I
want to see the channel-level activity of a single component. Is this the
correct approach?:

comp_chan_data = EEG.icaweights(comp_i,:)'.*EEG.data;
EEG.icaact(comp_i,:) = sum(comp_chan_data,1);

Where comp_chan_data is a nbchan x pnts or nbchan x trials x pnts matrix?
So, if I wanted to look at the contribution of a single component at
channel 15 I'd simply use comp_chan_data(15,:) or comp_chan_data(15,:,:)?

Is polarity adequately "undistributed" from the ICA decomposition back to
the channels with these transformations? Thanks.

Rob


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