[FieldTrip] ft_connectivityanalysis

Janssen, L.K. (Lieneke) lieneke.janssen at student.ru.nl
Mon Jul 18 17:28:48 CEST 2011

Hello again dear fieldtrippers, 

Last week I wanted to run my coherence script again, but unfortunately it didn't work with me anymore. I hadn't changed anything in either the input or settings, so it's a mystery to me. In addition, I have two other questions related to ft_connectivityanalysis.

1. I get the following error: 'Error using ft_selectdata, selection of or averaging across channels in the presence of both label and labelcmb is not possible'. 

-> My output from ft_freqanalysis and input to ft_connectivityanalysis = 'powerandcsd'. Eric didn't have the problem when using 'fourier', but then you don't get the field 'labelcmb' in your output. 

-> I can't help getting both label and labelcmb from freqanalysis if choosing 'powerandcsd'. If I remove the field 'label' from the structure, the function gives an error missing the field 'label' elsewhere. So I need both fields 'label' and 'labelcmb'. Previously, this problem did not exist. 

Did something change here? This brings me to point 2. 

2. I would like to run ft_connectivityanalysis for a selected group of channelpairs. Again, I get the aforementioned error. 
The same error I get if I run ft_freqdescriptives for a selection of channels (not all channels!, in contrary to my point 1... there I get the error both when I select channels as well as if I say channels = 'all'). Therefore I suspect that the first problem is caused by a bug in ft_connectivityanalysis, not in the more general function ft_selectdata that both ft_freqdescriptives and ft_connectivityanalysis make use of. Does that make sense?

3. In addition, I would like to calculate the standard error of my coherence output (if I can get it again at some point :)) using the method 'jackknife' (as recommended by Eric). ft_connectivityanalysis still has the option to use jackknife in its code, it just doesn't do anything with the setting anymore. The same goes for ft_freqdescriptives (but having it in ft_connectivityanalysis would do for me!). 

I hope the points I've made are a bit clear, otherwise please let me know. It's a serious problem for me not being able to run the coherence analysis, since I'm trying to finish my master thesis within a few weeks from now... So it would be great if somebody could help me! 

Thanks in advance :). 


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