[FieldTrip] Referencing

[Conrado Bosman]

Dear Hweeling,

There is indeed an easy way to re-referencing electrodes using local derivation in Fieldtrip.
You need to create an structure call montage, that in your case should be:

montage = []
montage.labelorg = {'E1' 'E2' 'E3' 'E4'}
montage.labelnew = {'E2-E1'  E3-E2'  'E4-E3'}
montage.tra = [1 -1 0 0;0 -1 1 0;0 0 -1 1];

then...

cfg = [];
cfg.reref = 'yes'
cfg.montage = montage;

dat = ft_preprocessing(cfg,dat) % dat is your original data structure containing your original channels

Hope it works!

Best,
Conrado


On 25 Feb 2014, at 10:32, Hwee Ling Lee <hweeling.lee at gmail.com> wrote:

> Dear all,
> 
> I have 4 electrodes, and I would like to reference my data by subtracting from the neighbouring electrode. In other words, E2-E1, E3-E2, E4-E3.
> 
> I was wondering if there is an easier way in fieldtrip to perform this calculation, and then to change the data structure with these new channel labels.
> 
> Thanks.
> 
> Cheers,
> Hweeling
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