[Eeglablist] Problems about DIPFIT

[lxraplikelx at qq.com]

Dear EEGLABLIST

Recently I am in trouble in using DIPFIT. I found a same problem in the archive of eeglablist but I couldn't find any solution. 

The problem is "atatype_raw error", and the error information is "inconsistent number of channels in trial 1". 

My dataset was average-referenced, and PCA to (EEG.nbchan-1) when I run ICA decomposition. I thought that maybe the discrepancy between the number of channels and components caused that (I actually know it must reduce the rank of the data when average-reference is used). Therefore I experimented not to reduce the rank of data, but directly run ICA. With the data of same numbers of channels and ICs, there is not aforementioned error any more. However, It resulted in bad dipole fitting (e.g. all dipoles are outside or converging to a same location). I do not know if my analysis pipeline is correct. My pipeline is below:

    1. import data (brain vision)
    2. 1-Hz high-pass filtering (considering good ICA results)
    3. clean line noise (CleanLine)
    4. downsample to 256-Hz
    5. load channel location and append online reference channel (FCz)
    5. average reference and add online reference channel back to data at the same time
    6. remove channels (VEO, HEOR)
    7. run clean_rawdata (only to identify bad channels)
    8. average re-reference
    9. epoch and baseline-correction with the mean of whole epoch data
    10. reject bad epoch (semi-automatic)
    11. run ICA (with 'pca', EEG.nbchan-1)
    12. DIPFIT ---> error

    PS: eeglab version is 13.2.2b; matlab version is 7.13.0.564 (R2011b)
    PPS: I will try Prep Pipeline to pre-processe data in the future, so with its robust average, it could also run into trouble for the unbalancing number of channels and ICs.
    
If any step of my pipeline is inappropriate and causes error I came across, please tell me. I appreciate your helps!

Best regards,

Li Xiang
Southwest University, China
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