[FieldTrip] ft_source2sparse usage for EEG data

[gj]

Thank you for your help, Jan Mathijs!

These are all the related steps I did leading up to the ft_source2sparse 
call, in case.

My input EEG data to FieldTrip are 2 seconds of passive visual 
stimulation, preprocessed and averaged across all trials per condition 
per subject in another software.

Thank you!
g

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cfg = [];
cfg.method = 'mtmfft';
cfg.output = 'fourier';
cfg.keeptrials = 'yes';
cfg.tapsmofrq = 2;
cfg.foi = 12;
fft = ft_freqanalysis(cfg, data);

cfg           = [];
cfg.output    = {'brain','skull','scalp'};
mri_seg  = ft_volumesegment(cfg, mri); % mri from standard_mri.mat (mm)

cfg=[];
cfg.tissue={'brain','skull','scalp'};
cfg.numvertices = [3000 1600 800];
mesh_hd=ft_prepare_mesh(cfg,mri_seg);

cfg = [];
cfg.method = 'bemcp';
headmodel = ft_prepare_headmodel(cfg, mesh_hd);

cfg = [];
cfg.grid.warpmni = 'yes';
cfg.grid.template = template_grid; % standard_sourcemodel3d10mm.mat
cfg.grid.nonlinear = 'yes';
cfg.mri = mri;
sourcemodel = ft_prepare_sourcemodel(cfg);

cfg                 = [];
cfg.elec            = elecR;	   % elec realigned to standard_bem.mat
cfg.headmodel       = headmodel;   % output from ft_prepare_headmodel
cfg.grid            = sourcemodel; % output from ft_prepare_sourcemodel
lf = ft_prepare_leadfield(cfg);

cfg = [];
cfg.frequency = fft.freq;
cfg.elec = elecR;
cfg.method = 'eloreta';
cfg.grid = lf;
cfg.vol = vol;               % from standard_bem.mat
cfg.keeptrials = 'yes';
%cfg.rawtrial = 'yes';
source = ft_sourceanalysis(cfg, fft);

cfg = [];
cfg.projectmom = 'yes';
source_proj = ft_sourcedescriptives(cfg,source);

------------- end snippet --------------