[FieldTrip] Adding Manual Markers

MUSTAFA YAVUZ m.yavuz.18 at ogr.iu.edu.tr
Wed Nov 25 02:03:20 CET 2020


Merhaba Stephen :),

Thank you for your informative response! Indeed, I already have data as
separate segments (trials) before any initiation with Fieldtrip. I was just
wondering if I can plot the event markers just for visualization purposes.
However, I've learnt why it is the case now. In my case, I believe a
solution would be ; concatenating the trials and manipulating the time axis
to arbitrarily create a single trial (continuous?) data  structure and then
building a custom trialfun to be able to visualize markers in
ft_databrowser.

Thank you again,
All the best,
Mustafa

Stephen Whitmarsh <stephen.whitmarsh at gmail.com>, 24 Kas 2020 Sal, 11:04
tarihinde şunu yazdı:

> Merhaba Mustafa,
>
> Welcome to FieldTrip!
> Just to be clear - I assume you segmented your continuous data into trials
> by passing your marker timing as a cfg.trl in ft_preprocessing, right?
> When you did, the temporal information about the markers became
> irrelevant, because the trials are then expressed *not *in samples from
> the onset of the continuous data anymore, but instead as time relative to
> the markers. I.e. each trial now starts at t=0s (-offset), rather and, say
> [13, 104, 206, ...] samples (i.e. your initial trl). See the resultant
> data.time field.
> Secondly, ft_databrowser does not take cfg.trl as the location of markers,
> rather it does so in cfg.artfctdef.xxx.artifact (yes, a bit strange, partly
> historical, and because databrowser is typically used to manually scan for
> artifacts).
>
> So, in your case, you could either:
>
> Use ft_databrowser to plot the original, unsegmented, continuous, data,
> and pass your trialinfo (as a Nx2 matrix, with only start and end sample)
> to cfg.artfctdef.xxx.artifact. Replace xxx with whatever your want, e.g.
> "trialnumber"
> Use ft_databrowser to plot the segmented data, as trials, with new
> time-axis, without the markers.
>
> Note that ft_databrowser will try to fit your cfg.artfctdef.xxx.artifact
> to your segmented trial data as well, by doing some intelligent checking of
> your past cfg (which is tracked in your segmented data structure and
> beyond), and treating your data as continuous data. That might work, or it
> might not, but now you know why!
>
> Happy fieldtripping,
> Stephen
>
>
>
> Op di 24 nov. 2020 om 02:29 schreef MUSTAFA YAVUZ <
> m.yavuz.18 at ogr.iu.edu.tr>:
>
>> Hi all,
>>
>> I've been trying to adjust my EEG data (segmented and .mat file) to be
>> analyzed by FT. I already have separate trials and have temporal
>> information about the event markers' time courses. I constructed a Nx3 trl
>> structure and passed it as cfg.trl while calling ft_preprocessing. Whilst
>> the function worked and I can see the cfg.trl field in the output
>> structure, when I call ft_databrowser, the event markers are not displayed
>> on trials. Do you have any idea/solution for this situation?
>>
>> Thank you in advance,
>> Mustafa
>>
>> --
>> *Mustafa Yavuz *
>>
>> Ph.D. Candidate in Neuroscience
>>
>> Department of Neuroscience
>> İstanbul University
>>
>> _______________________________________________
>> fieldtrip mailing list
>> https://mailman.science.ru.nl/mailman/listinfo/fieldtrip
>> https://doi.org/10.1371/journal.pcbi.1002202
>>
> _______________________________________________
> fieldtrip mailing list
> https://mailman.science.ru.nl/mailman/listinfo/fieldtrip
> https://doi.org/10.1371/journal.pcbi.1002202
>


-- 
*Mustafa Yavuz *

M.Sc. Candidate in Neuroscience

Department of Neuroscience
İstanbul University
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20201125/cc681d60/attachment.htm>


More information about the fieldtrip mailing list