[Eeglablist] Interpolation and ICA

Bernhard Meyer a0302186 at unet.univie.ac.at
Mon Jan 4 16:20:25 PST 2010

As I need to use the algorithm eeg_interp(EEG, Channel, 'spherical') for
channel-interpolation in combination with ICA I found a possible
contradiction regarding the question what to apply first, ICA or

Arno Delorme wrote in 2006 (Archive): 'Note that it is not recommended
to perform interpolation before running ICA. The attached function will
take care of you ICA information when you perform interpolation.'

Andreas Widmann wrote in 2009 (Archive): 'However, be aware that a
possibly existing ICA weight matrix will be invalid as only part of the
dataset is interpolated!'

In my opinion I would run ICA after interpolation. On the one hand I
am afraid to have invalid ICA-data in the end, especially if I
interpolate just a part of the epochs of the channel. On the other hand
I want to have all channels as clean as possible, otherwise I could lose
degrees of freedom for useless data.
I hope the EEGLAB-community can clarify that step.

Bernhard Meyer

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