[Eeglablist] Question about Order of rereferencing and artifact removal

[Steven Pillen]

Hello, EEGLABList.

There was a question we had at our lab about the order of operations when
it comes to rereferencing and other steps of preprocessing.  Is considered
better to remove artifactual data before rereferencing to the average, or
before filtering the data?

In addition, when we tried to rereference to the average immediately after
removing artifactual data, when we got to the point where we tried to run
ICA, we got an error message that read:

"EEGLAB has detectat that the rank of your data matrix is lower the number
[sic] of input data channels.  This might be because you are including a
reference channel or because you are running a second ICA decomposition.
 The proposed dimension for ICA is 31 (out of 32 channels). Rank
computation may be innaccurate so you may edit this number below.  If you
do not understand, simply press OK."

It would not run with either 31, or 32 channels, and we're not sure why.

Does anyone have any insight as to why?

Thank you,
Steven Pillen
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