[FieldTrip] Negative values of debiased wPLI

[Ramin Azodi]

Hello,

I a bit confused about result which I got from debiased wPLI, because it
has the negative value inside the 'wpli_debiasedspctrm'. As I searched for
that I found this strange explanation,

"...We therefore estimated the squared wPLI by using the debiased wPLI
estimator (Vinck et al., 2011), ranging from zero *(negative values can
incidentally occur because of limited sampling)* to one (maximum
coherence)......."

Beta coherence within human ventromedial prefrontal cortex precedes
affective
value choices, N. Lipsman  et al, NeuroImage 85 (2014) 769–778.

Could someone explain me, what it means and what should I do with these
negative values?

Best,
Ramin
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