[FieldTrip] ft_source2sparse usage for EEG data

gj gina.joue at univr.it
Wed Apr 6 17:42:47 CEST 2016

Hi FieldTrip community,

Sorry for the onslaught of newbie questions.

I would like to run a whole-brain network analysis on source level on a 
2-sec continuous recording of EEG data. Following the tutorials (for 
MEG), I first run ft_source2sparse to reduce the matrix to only voxels 
inside the skull:

>> source_sparse = ft_source2sparse(source_proj);
total number of dipoles        : 6804
number of dipoles inside  brain: 3294
number of dipoles outside brain: 3510

When I then try to run the connectivity analysis 
(ft_connectivityanalysis), regardless of which connectivity method, I 
get the error:

---- error ---
Requested 92232x92232 (126.8GB) array exceeds maximum array size 
preference. Creation of arrays greater than
this limit may take a long time and cause MATLAB to become unresponsive. 
See array size limit or preference
panel for more information.

Error in univariate2bivariate (line 314)
           data.crsspctrm = (transpose(mom)*conj(mom))./nrpt;

Error in ft_connectivityanalysis (line 434)
         [data, powindx, hasrpt] = univariate2bivariate(data, 'mom', 
'crsspctrm', dtype, 'cmb', cfg.refindx,
         'keeprpt', 0);

----end error---

I guess it is related to how I might have created the sourcemodel 
(ft_freqanalysis run with method='mtmfft', output='fourier', 
keeptrials='yes')?  I am using FieldTrip ver.20160309.

Thank you very much in advance for any help!

More information about the fieldtrip mailing list