lcmv localization

Luca Ciancetta luca.ciancetta at TISCALI.IT
Tue Oct 31 18:28:50 CET 2006

Dear List members,

I'm trying to localize a source with the lcmv method.

Following, it's the configuration I use:

time_step = 1/h.smpfq; % the time step depends by sampling frequency
time = 0:time_step:(500*time_step); % I want to see 500 points of data

data.trial{1} = data_raw(gch,0:500); % gch: list of good channels
data.time{1} = time;

cfg = [];
cfg.method = 'lcmv';
cfg.grid.pos = model; % model is a matrix [number_of_sources X 3].
This represent position of dipoles in the reference of the sphere
which contains them.
cfg.grad.tra = zeros(nch,nch); % number of good sensors ( size of 'gch' list )
for i=1:nch
     cfg.grad.pnt(i,: ) ='; %
positions of MEG sensors in the reference of the spherical model
     cfg.grad.ori(i,: ) ='; %
orientations of MEG sensors in the reference of the spherical model
     cfg.grad.tra(i,i) = 1;
     cfg.grad.label{i} = sprintf('MZ_%d\n',gch(i)-1);

cfg.vol = [];
cfg.vol.r = 65;

cfg.bpfilter      = 'yes';
cfg.bpfreq        = [1 100];

data.avg = squeeze(data.trial{1});

source = sourceanalysis(cfg,data);

In this case I used only one trial and the result is a localization
in the center of the sphere ( the source is a dipole simulation, it
was placed on the surface of my spherical model).
Also analyzing over more trials or using different data set, for
example a median nerve stimulation, the result was the same.

can you help me?


More information about the fieldtrip mailing list