[FieldTrip] Help Manually Defining Trials

[Stephen Politzer-Ahles]

Hi Peter,

http://www.fieldtriptoolbox.org/reference/ft_definetrial describes the
format of the trial definition matrix; you can simply create a matrix like
this using the times that you would like to choose for your epochs, and
then run ft_preprocessing() with this matrix as the input for cfg.trl.
(This is basically a combination of methods (1) and (2) that you suggested
below.)

Best,
Steve


Stephen Politzer-Ahles
New York University, Abu Dhabi
Neuroscience of Language Lab
http://www.nyu.edu/projects/politzer-ahles/

On Mon, Jun 29, 2015 at 2:00 PM, <fieldtrip-request at science.ru.nl> wrote:

>
>
> Message: 1
> Date: Sun, 28 Jun 2015 23:51:19 -0400
> From: Peter Lyons <plyons at udel.edu>
> To: FieldTrip discussion list <fieldtrip at science.ru.nl>
> Subject: [FieldTrip] Help Manually Defining Trials
> Message-ID:
>         <CALq-V2qi104MwTnq26qr4EwKPkZkBMEBzstS5JPRxZKVMrr=
> sw at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Dear All,
>
> My name is Peter Lyons, and I am a researcher at the University of
> Delaware.  Currently, I am conducting resting state EEG research with the
> intention of using Fieldtrip to calculate the power of different frequency
> bands as well as phase lag index between various sensors.  My dataset is a
> continuous recording sampled at 1000 hz for 30 minutes.  I do not have any
> events or triggers in my data.
>
> I would like to manually select the cleanest segments of my data following
> artifact rejection, and define them as trials.
>
> Theoretically, I see three ways to segment my data manually:
>
> 1.  Insert individual triggers throughout my data (at locations determined
> via ft_databrowser), and then define trials based on these triggers.
>
> 2.  Define trials based on a beginning and ending sample number.
>
> 3.  Use ft_databrowser to select segments of data as if they were
> artifacts, and then define these "artifacts" as trials instead of rejecting
> them from the dataset.
>
> Could anyone advise on how to code one of the above methods?
>
> Any help is welcome and appreciated!
>
> Thanks,
> Peter
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