[FieldTrip] Concatenate different size of trials into single one trial

Yadwinder Kaur yadwinder.kaur at stud.uni-greifswald.de
Sun Jul 1 23:00:55 CEST 2018

Hi Jan
Thanks for your reply.My idea was to extract trials (based on stimulus
followed by response) , perform preprocessing and at the end
concatenate them together, because my aim is to further divide the
concatenated segment into four parts to perform latent variable
analysis. Am I doing wrong in this way? 

On Sunday, 01-07-2018 at 20:16 Schoffelen, J.M. (Jan Mathijs) wrote:

 Hi Yadwinder, 

Why would you want this? 

For this purpose, ft_appenddata is not your friend, if you want to
‘create a single data matrix’. It concatenate a bunch of matrices,
you can use cat(2,data.trial{:}), but this will only be a meaningful
operation in a very limited number of cases. Most of the time, the
last time point of trial n-1 will not be temporally aligned with the
first time point of trial n, and even if that were the case, trial
specific filtering, baseline correction, or any trial-specific
processing in general will lead to discontinuities in the signals.

Best wishes,



 On 30 Jun 2018, at 15:06, Yadwinder Kaur  wrote:

Dear All

I have pre-processed my EEG data cutting into different trials (35
trials total) using fieldtrip , now I wish to concatenate them into
one single data matrix. The length of each trial varies form each

ofcourse, ft_appenddata didn't work in this case.

I would highly appreciate any help to solve this issue.

Thanks in advance.

Yadwinder _______________________________________________
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