Error: DC offset - Cell contents reference from a non-cell array object

Discussions
1

I am trying to run a dc offset to my raw files.
Half of them run fine and the other half say that the cell reference is not an array.

i looked at the file contents and there appears to be no difference between working and non working files.

ERROR BELOW
** Error: [process_baseline] Pre-process > Remove DC offset
** Cell contents reference from a non-cell array object.
** File: 43b-stim_b/@raw43b-2b-stim/data_0raw_43b-2b-stim.mat

Any thoughts on what i am doing wrong?

Thanks
Josh

2

Hi Josh,

Can you please post the full error message?
Could you also send me one of the files you’re having trouble with?
(upload it somewhere, eg dropbox, and send me then link in a separate email - click on my user name on this forum)

Thanks,
Francois

3

Hi Josh,

I looked at your file and could not reproduce the error you mentioned. But I probably didn’t do exactly what you did.
I need more precise directions on what you did with these files: list exactly all the operations you did, step by step, and add screen captures of the processes that have many options (like the ICA).

I have a few comments about your pipeline:

Things i have done to these raw files.
Run an ica
changed the mastoid channels from eeg to misc
added the position icbm152 neuroscan 64 quick cap
manually rejected artifact.

  1. You should first change the type of the channels and then run the ICA
  2. I would recommend you also add the positions before the ICA, otherwise you cannot look at the topography of the ICA components (which is a mandatory step)
  3. You should also change the type of channel HR to “ECG”
  4. Manual artifact rejection: this is not something I can reproduce on my end
  5. I would recommend you run the DC offset correction while importing the recordings instead of on the continuous files, unless you have a really good reason to it this way. Another common way to remove the DC is to apply a high-pass filter to the recordings.

Francois

4

Also, make sure you update Brainstorm first, so we are testing the exact same thing.

5

I managed to fix this by removing extraneous head location data in the channel file which had for some reason populated the word EXTRA over and over again.

6

Hello,
The field .HeadPoints.Label is supposed to be populated with “EXTRA” strings, for all the points that are not anatomical landmarks (NAS, LPA, RPA). This convention comes from the Elekta Neuromag .fif files.
Francois