[FieldTrip] Working with own data format - events

Eelke Spaak eelke.spaak at donders.ru.nl
Wed Mar 16 15:59:09 CET 2011

2011/3/16 Marco Dahmane <marco.dahmane at gmail.com>:
> A (very) simple example of what I want to do would be : given that my trials
> are each about 8 seconds long, let's say the region of interest for me spans
> from 3s to 6s in every trial subset. How would I write that in FT ?

This could indeed best be achieved by using ft_redefinetrial, just
specifying as time limit from 3s to 6s and then conducting your
analyses on the resulting data slices.

> And what if on certain trials only, I spot a very interesting spike. Does FT
> allow me to put an event marker on that specific spike ? If yes, how so?
> Am I being any clearer now?

If you want to mark the trial in which that interesting spike
occurred, you could dedicate an extra column in your data.trialinfo
matrix to this, e.g., place a 1 there for every trial that contains
such an interesting spike. Then, just use cfg.trials = find(...) again
in subsequent steps to limit analysis to trials containing interesting

Or, if you want to mark the exact time at which such a spike occurs
(relative to the trial), you could use Jan-Mathijs' suggestion and
have a column in your data.trialinfo correspond to the sample index of
the spike, relative to the trial. ft_redefinetrial could then slice
out the interesting parts, if you specify cfg.begsample and


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