Neuromag stats

[Thomas Thesen]

Hi FieldTrippers,

I am trying to run clusterrandanalysis on single-subject data that have been
collected on a Neuromag system. It seems that I am running into problems
with the neighbouring channel geometry.
The epochs are already in a format that went through timelockanalysis and
gives the following structure:

timelock_data = 

           avg: [102x102 double]
           var: [102x102 double]
       fsample: 250
    numsamples: [297x1 double]
          time: [1x102 double]
        dofvec: [1x102 double]
         label: {1x102 cell}
         trial: [297x102x102 double]
        dimord: 'rpt_chan_time'
          grad: [1x1 struct]
           cfg: [1x1 struct]


When trying to run the data through clusterrandanalysis using:

cfg = [];
cfg.statistic = 'depsamplesT';
cfg.alphathresh = 0.01;;
cfg.makeclusters = 'yes';
cfg.minnbchan = 0;
cfg.clusterteststat =  'orderedsums';
cfg.smallestcluster = 5; 
cfg.onetwo = 'twosided';
cfg.alpha = cfg.alphathresh ; 
cfg.nranddraws = 10;
cfg.gradfile = data.grad.pnt;

[clusrand] = clusterrandanalysis (cfg, timelock_data, timelock_data);

It gives the following error message:


Selecting and formatting the data.
selected 102 channels
selected 1 time bins
selected 1 frequency bins
Calculating the neighbourhood structure of the channels.
Obtaining the gradiometer configuration from a file.
??? Error using ==> exist
The first input to exist is a string.

Error in ==> read_fcdc_elec at 60
if ~exist(filename)

Error in ==> clusterrandanalysis>getneighbgeometry at 496
        data.grad = read_fcdc_elec(cfg.gradfile);

Error in ==> clusterrandanalysis at 461
[cfg,data] = getneighbgeometry(cfg,data,varargin{1});



There seems to be some problem with the gradfile, but I am not sure what
exactly.

 data.grad.pnt contains the sensor configuration. Here is an excerpt:

    0.0545   -0.1029    0.0548
    0.1002    0.0059    0.0467
    0.1002    0.0059    0.0467
    0.1023   -0.0238    0.0226
    0.1023   -0.0238    0.0226
    0.0946   -0.0541    0.0357
    0.0946   -0.0541    0.0357
    0.0972   -0.0246    0.0603
    0.0972   -0.0246    0.0603

The data file timelock_data.m can be downloaded at
http://mmil.ucsd.edu/thomas/FT/
if someone could be so nice to have a look at it, I'd really appreciate it.

Thanks a lot,

Thomas