[FieldTrip] problems with ft_redefinetrial - data seem inconsistent afterwards (sample info - timepoints problem?)

[Mazzetti, C. (Cecilia)]

Hello everyone,

I am facing a problem when running ft_timelockanalysis on preprocessed MEG data, whose onset have that has been re-defined with ft_redefinetrial (with option cfg.offset). Specifically, stimulus locked data were re-defined to be response locked.

Now, I have to run time lock analysis to later apply LCMV beamformer.

Unfortunately, for some subjects (inexplicably, to me) I encounter the following error:


when running:

cfg                       = [ ];

cfg.covariance     = 'yes';
cfg.keeptrials       = 'yes';
tmlock_resp         = ft_timelockanalysis(cfg, megresp);


the input is raw data with 270 channels and 235 trials
the call to "ft_selectdata" took 1 seconds and required the additional allocation of an estimated 2 MB
Unable to perform assignment because the size of the left side is 1-by-270-by-2348 and the size of the right side is 270-by-2349.
Error in ft_checkdata>raw2timelock (line 1527)
    tmptrial(i,:,begsmp(i):endsmp(i)) = data.trial{i};
Error in ft_checkdata (line 468)
      data = raw2timelock(data);
Error in ft_timelockanalysis (line 144)
  datacov      = ft_checkdata(datacov, 'datatype', 'timelock');



I know this seems to be something related to the number of trials, or timing (in those datasets, I also cannot seem to cut epochs to get shorter time windows) but I checked the data and sample info, and everything seems ok (I also don't know what that 2348 - 2349 refers to)


Someone knows what this error refers to? Maybe how to fix it or where to look into?

Importantly, if I do not redefine those data everything goes fine (meaning if they stay stimulus locked).

Is something going on during ft_redefinetrial?



Thanks in advance to all a lot!





All the best,
Cecilia

Cecilia Mazzetti, Postdoc Researcher
Department of Basic Neurosciences
University of Geneva
Chemin des Mines 9,
1202 Genève, Switzerland


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