[FieldTrip] WPLI

[Xie Wanze]

Dear Linzhang,
As Cris mentioned, you cannot calculate the WPLi value with one trial. The
WPLI toolbox calculates the CSD and PSD for each single trial, and then get
the "correlation" of the phase information across trials.  This apparently
could not be done with one trial.
If you have continuous data you may try to segment it into epochs.

Wanze


Cristiano Micheli <michelic72 at gmail.com>于2017年9月4日 周一上午7:35写道：

> Dear Linzhangysu
>
> the wPLI metric requires you to have your experimental design matrix
> organized in 'repetitions' or 'trials'.
> This is typically the case (but not only) of an evoked related design,
> where the repetitions dimension is used to calculate your 'average' wPLI
> across trials, and this is what the FT code is doing for you in the
> *ft_connectivity_wpli* function.
> In summary, with this formula you will not be able to apply wPLI to a
> single trial (e.g. like in resting state). If your experiment allows
> organizing the experimental data into 'trials' (with the operation of
> epoching) then you can solve your problem, otherwise you will have to use
> other metrics of phase coupling.
>
> IHTH
> Cris Micheli
>
>
>
> On Mon, Sep 4, 2017 at 1:09 PM, linzhangysu at outlook.com <
> linzhangysu at outlook.com> wrote:
>
>>
>>
>> [image: cid:image002.png at 01D325AA.E537BE20]
>>
>>
>>
>> I want to calculate the WPLI of 64 channels for one subject. But I met
>> some questions.
>>
>> Firstly, I didn’t understand the meaning of repetitions (just as the
>> maker of the figure ). The dimension of repetitions was 1 in my MATLAB code
>> , which resulted  in the WPLI result are NaN vectors. How can I solve the
>> problem about ‘repetitions’?
>>
>> I am looking forward to your reply very urgently, Thank you !
>>
>>
>>
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>
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