[FieldTrip] surrogates for Phase lag index

[HINDRIKS, RIKKERT]

http://www.vis.caltech.edu/~rodri/papers/PNB.pdf


On Wed, Jul 9, 2014 at 10:10 PM, Bastien Boutonnet <bastien.b1 at gmail.com>
wrote:

> That makes sense. How would you implement phase-randomisation? Is it
> similar to estimating the connectivity between the same pairs of electrodes
> but with data coming from different trials? Or even simpler?
>
> My interest to know about PLI/wPLI however still holds.
>
> B
>
> –
> Bastien Boutonnet, Ph. D.
> Postdoctoral Research Associate
> Department of Psychology
> University of Wisconsin, Madison
> bastienboutonnet.com
>
>
> On 9 July 2014 14:42, HINDRIKS, RIKKERT <rikkert.hindriks at upf.edu> wrote:
>
>> Constructing surrogate time-series for PLV is more straightforward since,
>> in this case, the nullhypothesis is the absence of phase-locking.
>> Surrogate pairs of time-series can be constructed for example by
>> phase-randomization in the Fourier domain.
>>
>> Rikkert
>>
>>
>> On Wed, Jul 9, 2014 at 9:01 PM, Bastien Boutonnet <bastien.b1 at gmail.com>
>> wrote:
>>
>>> I guess I will tag along to this discussion, in saying that I have been
>>> having the same burning question for a while.
>>>
>>> My issues have been along those lines: when I run some kinds of
>>> connectivity analyses (be it PLI, wPLI or PLV), how do I make sure the
>>> values I obtain are "legal" (or different from 0).
>>>
>>> B
>>>
>>> –
>>> Bastien Boutonnet, Ph. D.
>>> Postdoctoral Research Associate
>>> Department of Psychology
>>> University of Wisconsin, Madison
>>> bastienboutonnet.com
>>>
>>>
>>> On 9 July 2014 13:39, HINDRIKS, RIKKERT <rikkert.hindriks at upf.edu>
>>> wrote:
>>>
>>>> Hi Lidia,
>>>>
>>>> I have the same question and I don't think the answer is trivial: one
>>>> would have to construct pairs of surrogate time-series under the
>>>> nullhypothesis of zero phase-lag-index. With other words: construct
>>>> pairs of time-series who's instantaneous phases are coupled
>>>> to the same extent as the recorded time-series but with zero lag. In my
>>>> case, the question is how to test for a significant lag via the
>>>> cross-correlation function.
>>>>
>>>>
>>>> Kind regards,
>>>> Rikkert
>>>>
>>>>
>>>> On Wed, Jul 9, 2014 at 8:18 PM, Lidia Mijas <lid.mijas at gmail.com>
>>>> wrote:
>>>>
>>>>> Hi all,
>>>>>
>>>>> I am wondering if fieldtrip has any options for computing surrogates?
>>>>> I am tryng to assess confidence level for my Phase Lag Index results (
>>>>> to determine whether it is significantly larger then 0)
>>>>>
>>>>> But maybe someone has a better idea how to do it?
>>>>> Not sure if it matters so just to mentioned that my PLI was computed
>>>>> at the source level on beamformed signals.
>>>>>
>>>>> Many thanks for any suggestion.
>>>>>
>>>>> Lidia
>>>>>
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>>>>>
>>>>
>>>>
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>>
>>
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>
>
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