[FieldTrip] Sample script for spike+LFP analysis?

Stan van Pelt stan.vanpelt at fcdonders.ru.nl
Tue Jan 21 10:23:00 CET 2014

Hi Jay,

In addition to Eelke's reply, you may also find the examples in these
pages useful in creating your trial definition (cfg.trl):


Stan van Pelt, PhD
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognition
Montessorilaan 3, B.01.34
6525 HR Nijmegen, the Netherlands
tel: +31 24 3616288

-----Original Message-----
From: fieldtrip-bounces at science.ru.nl
[mailto:fieldtrip-bounces at science.ru.nl] On Behalf Of Eelke Spaak
Sent: dinsdag 21 januari 2014 9:30
To: FieldTrip discussion list
Subject: Re: [FieldTrip] Sample script for spike+LFP analysis?

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
> 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
> _______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip

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