Re: [Erppcatoolkit-support] Problem loading/appending data and question

[Andreas W. <wi...@un...>]

Dear Joe,

> Sorry for long delay!  I came down with a really bad cold.
Oh, I hope you have fully recovered!

> 1) Could you send me a copy of your file so I can test it out?  I can’t assume that all such files would trigger the error.
I will send two files in a separate mail without copy to the list. I hope this is ok.

It is well possible (likely? ;) that I use the function in an incorrect or unintended way (and it worked in previous versions by accident). I try to add a second (within subject) condition to an already loaded grand-average dataset by appending a cell. Reading the first dataset (e.g., gavr-d.set, order doesn’t matter) from my EEGLAB grand-average works flawlessly. Trying to Edit -> Cells -> Append the second dataset (gavr-s.set) gives the reported error (because EPdataIn.trialSpecs is empty).

Should I add the condition/cell in a different way? Should I store both conditions in a single grand-average file? How to encode/store condition information then?

> I’d don’t remember exactly why I made the change but expect it was to fix a bug of some sort.
> I’ll see what I can do to come up with a better solution.
Thanks a lot!

> It’s not possible to use the Single File Mode since it is designed for files where each file is a single waveform and the Widmann variant by definition has multiple waveforms in it.
Ok.

> 2) I’ll take a closer look at it.
> 
> 3) I think that approach makes sense.  I do much the same for the function where it provides a test of the lateralization of dipole pairs.
Very good! Thank you!

Best,
Andreas

> Cheers!
> 
> Joe
> 
>> On Mar 31, 2015, at 13:11, Andreas Widmann <wi...@un...> wrote:
>> 
>> Dear Joe and list!
>> 
>> Thank you for providing your toolbox (and supporting the „Widmann variant“ of the EEGLAB file format; which I didn’t even know that it exists :)))! May I ask three short questions?
>> 
>> (1) I have a problem appending cells with the above mentioned file format in 2.47 and 2.48 but not in 2.45:
>> The error is:
>> 
>> Conversion to double from cell is not possible.
>> Error in ep_addData (line 287)
>>                EPdataOut.trialSpecs(end+1:end+numAdded,:)=cell(numAdded,size(EPdataIn.trialSpecs,2));
>> Error in ep_editData (line 2666)
>>            EPoverview.workData=ep_addData(EPoverview.workData,newData,'cells'); 
>> Error while evaluating uicontrol Callback
>> 
>> If I add a check in ep_addData whether EPdataIn.trialSpecs is empty (as it was in previous versions) it works:
>> if ~isempty(EPdataIn.trialSpecs)
>>                EPdataOut.trialSpecs(end+1:end+numAdded,:)=cell(numAdded,size(EPdataIn.trialSpecs,2));
>> end
>> 
>> Would you expect any unexpected side effects from this workaround? Why did you remove the check? (Btw: Is there a way to use the single cell file mode for reading this file format? Couldn’t get that to work. Most probably due to my ignorance.)
>> 
>> (2) Only short suggestion: In ep_addEloc, line 134 ...
>>        if ~isempty(eloc(i).labels) && ~isempty(eloc(i).theta) && isempty(eloc(i).type)
>> … it could be helpful to check whether theta is numeric before wiping. EEGLAB pop_chanedit always ignores type when importing ced-files even if it is contained in the file. This practically disables importing electrode locations if one does not know that the type field has to be filled manually.
>> 
>> (3) My main question: I would like to compare the oddball P3a component latency with the latency of some other external non-ERP psychophysical measurement. Usually, we would do this using jackknifing with some relative peak amplitude criterion. However, I would prefer doing this with a „true" PCA-P3a component and not the ERP-P3a. I cannot separate N1/P2/P3a components with spatial PCA as they are too similar. Now, I hope my question is not too stupid: Do you think it would be a valid approach to do so some kind of jackknifing temporal PCA? That is, performing several temporal PCAs omitting one subject and estimating jackknifing latency from each of the resulting PCA-P3a component time courses?
>> 
>> Thank you! Best regards,
>> Andreas
>> 
>> 
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