[FieldTrip] Sample script for spike+LFP analysis?

Eelke Spaak eelke.spaak at donders.ru.nl
Tue Jan 21 09:30:14 CET 2014

Hi Jay,

A "trl" matrix is an Nx3 matrix that gives, for each of N trials, the
begin and end sample, and the 'offset' (shift in time axis to
determine t=0; offset=0 means begin sample will be t=0).

In typical cognitive experiments, such a matrix is generated by a call
to ft_definetrial, which in turn calls either a user-specified
"trialfun" to find events of interest in the data (recorded in a
trigger channel), or ft_trialfun_general. ft_trialfun_general is a
simple trialfun that looks for specified event values in a specified
trigger channel, and creates trials spanning from X seconds before the
event to Y seconds after the event. For using ft_definetrial, see this
tutorial: http://fieldtrip.fcdonders.nl/tutorial/preprocessing

If for any reason (e.g. you don't have triggers) you don't want to use
ft_definetrial, you can simply create a trl matrix yourself by
specifying the sample indices and offset.


On 21 January 2014 02:30, Jay Hegdé <jhegde at gru.edu> wrote:
> Hi Everyone,
> I'd like to use FieldTrip for the joint analysis of spike and local field
> potential (LFP) data.  I'm proficient in Matlab, but very new to FieldTrip.
> I'm trying to write a script by precisely following the relevant tutorial
> (http://fieldtrip.fcdonders.nl/tutorial/spikefield). Everything goes OK for
> the first couple of steps, but I'm getting stuck when it comes to
> constructing "a cfg.trl matrix to preprocess the LFP data" described in the
> tutorial.
> So can anyone share an example script that actually runs and does this
> analysis, so I can see what the tutorial is talking about?
> Thank you very much in advance,
> Jay Hegdé
> Medical College of Georgia
> Georgia Regents University
> Augusta, GA, USA
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> fieldtrip at donders.ru.nl
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