[Eeglablist] How to add channels/ channel-number problem

[Makoto Miyakoshi]

Dear Florian,

> to prepare my EEG data for ERP analysis, I removed bad channels (noisy
from tDCS and one GSR channel) in my datasets using *“Edit>select
data>channel range (the remove box ticked)” *in the gui. When I calculated
grand averages (using the ERP-toolbox), logically, the error “different
numbers of channels” occurred.

Though I have never used ERP-toolbox, this does not sound right. After
removing the channel, save the set file, close matlab, load the saved data
and do the same process to see if the problem is replicated.

Makoto

On Sun, Jun 29, 2014 at 5:12 AM, Florian Faehling <
florian.faehling at gmail.com> wrote:

> Dear EEGLAB-community,
>
>
>
> to prepare my EEG data for ERP analysis, I removed bad channels (noisy
> from tDCS and one GSR channel) in my datasets using *“Edit>select
> data>channel range (the remove box ticked)” *in the gui. When I
> calculated grand averages (using the ERP-toolbox), logically, the error
> “different numbers of channels” occurred.
>
>
>
> I therefore tried to add new channels  with both the “append channel” in
> the “Edit-> channel locations” gui of eeglab and “EEG-channel operation” of
> the ERP-toolbox-GUI . I do get the same amount of channels in the datasets
> then, yet now the error “matrix dimensions must agree” when I try any
> operation such as interpolating the channels.
>
>
>
> Is there any way of adding channels or better, edit the channel numbers? I
> fear that this problem is due to my rather premature understanding EEGLAB
> and would very much appreciate any explanation of what I did wrong on a
> deeper level (I assume that I somehow changed the channel numbers in the
> dataset yet not in the channel location file etc?).
>
>
>
> Also, I would be very grateful for an advice of how to treat bad channels
> in a more sensible way, when, as in my case, it is inevitable to remove
> some of them ( I read that interpolating them before ICA is not advisable
> and had the above described option from an EEGLAB lecture online)
>
>
>
> Thank you so much for ideas & sorry if this is a hypercomplication of a
> for you seemingly trivial error J
>
>
>
> Florian Faehling
>
> Tübingen
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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