[FieldTrip] import own format (long trials)

gj gina.joue at univr.it
Fri Mar 18 19:08:42 CET 2016


In case anyone else is having the same problem, my mistake was how I set 
"data.time".

According to the FT Wiki, "data.time" should be a "cell-array containing 
a time axis for each trial (1 X Ntrial), each time axis is a 1*Nsamples 
vector"

but it should be in seconds and I had specified it in number of samples 
instead, which triggered the error

            Error using ft_specest_mtmfft (line 96)
            "the padding that you specified is shorter than the data


On 16/03/16 19:07, gj wrote:
> Hi,
>
> I am trying to import EEG data preprocessed and averaged in BrainVision
> Analyzer. I have a 2-second segment of data per condition per subject
> which corresponds to the averaged signal across all trials of each
> condition for the subject.
>
> Is the following approach correct?
>
> Import the 4 conditions as 4 long trials (2 sec or 2000 samples with
> sampling freq of 1000 Hz)
> => data.trial is a 1x4 cell array
>     and each cell array contains an nchan x 2000 matrix
>
> I am trying to fill in the other fields of the data structure to mimic
> FieldTrip's raw data but I think I am having problems with
>      data.sampleinfo
> which, if I understand correctly, needs to be specified for long trials.
>
> According to the wiki, this should be an array containing [startsample
> endsample] to specify the position of each trial, with info for each
> trial on every row. However, it doesn't seem right to have
> data.sampleinfo = repmat([1 2000],4,1)
>
> Thanks in advance for any help!
> Gina



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