[FieldTrip] databrowser and merged data

[Eelke Spaak]

Dear Marco,

Let me make three points in response to your question.

(1) Actually, in general, timelock data structures should never
contain sampleinfo, since sampleinfo describes which samples in the
original recording your trials correspond to (I'm not sure about
timelocked data with cfg.keeptrials='yes').

(2) However, I don't think that point (1) is relevant to your problem.
More relevant is this: why do you want to use the databrowser to
visualise timelocked data? The databrowser is meant to conveniently
page through data with a big time axis. Usually, your timelocked data
will not have a big time axis, but a small one. For this, we have the
ft_singleplotER-function, or simply matlab's plot().

(3) When you provide data that lacks a sampleinfo field to a fieldtrip
function that requires a sampleinfo field, the sampleinfo should be
automatically constructed. (This is taken care of by ft_checkdata,
which is also responsible for converting your timelocked data into raw
data in case you pass it to the databrowser.) So, even if you decide
that you really want to use the databrowser to display timelocked
data, it should actually just work :) Are you using the latest version
of fieldtrip? If so, could you provide me with some more details on
the error and its circumstances?

Best,
Eelke


2011/8/8 Marco Dahmane <marco.dahmane at gmail.com>:
> Hi all,
> I have a rather straightforward question. I would like to be able to
> visualize the output of ft_timelockanalysis in butterfly mode using the
> databrowser function.
> However, since my data was made by merging several raw datasets together,
> the sampleinfo field was erased during the process, and databrowser doesn't
> like that (even though the timelock.time and timelock.avg fields are fine)
> What I would like to know is, since I have quite a lot of small datasets to
> be merged together, is there a way to make FT automatically reconstruct the
> sampleinfo field after merging two datasets together ? In other words, do I
> *have* to manually add the sampleinfo field at the end (and how come it is
> lost upon merging two datasets?)?
> And if yes, what is the easiest way to go about it?
> Many thanks,
> --Marco
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