[FieldTrip] calculating the ITC or PLV from animal EEG data

Russell G Port russgport at gmail.com
Thu Jan 3 23:02:29 CET 2013

Hello All,

I was hoping someone could lend me a hand with an issue I have. I have
animal EEG sets, which I have processed with fieldtrip. Each animal had 1
electrode and one reference electrode, and were run in a CED system. From
the way it was setup in the past; each animal was listed as a channel. I.E.
channel 1
corresponded to animal 1, etc etc. When I read it into fieldtrip,as would
be correct normally each channel is again an animal and each run it a data
set (which
would normally be a subject). This is fine, since I have found ways to work
around this, and can also separate each animal's data into seperate data
and rename their channel "electrode 1". What interests me though is
computing the phase-locking value over trials, and/or making grand averages
of the phase-locking
value over certain conditions (a certain subset of mice), I think another
name for this phase-locking value would be intertrial coherence..? I am
found useful things on
this board, i.e. to use ft_connectivityanlaysis, or using

tmpdat = freq.fourierspctrm;

tmpdat = tmpdat./abs(tmpdat); ; % this will normalise each trial for
its amplitude;
itc = abs(mean(tmpdat)); % this will give the itc

>From reading other messages I know that everyone on this board is
knowledgeable. How would other people compute this PLV for the kind of
data I have? Is it the same as

ITC? I assume theres critical details that I am glossing over. Lastly
is there a way using ft_singleplotERS, to plot this PLV measure (or
atleast measure of

coherence), since when plotting cross-spectra you would need a
reference channel?


Russell Port

Upenn Neuroscience Graduate Group
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