[FieldTrip] sloreta doest not get unity source variance

[Yiyao Ye Lin]

Dear researchers,

 

I am sorry to not formulate correctly the question. In the attached file I attempted to explain my doubt. Hope that you can understand my question this time and can help me to better understand sLortea. 

 

What I can not understand is that sLoreta is standardized minimum norm solution, the source covariance matrix should be identity matrix. However, I could not check this. I think that there be something that I did not understand correctly.

Thank you very much for your attention

Best regards

*******************

Yiyao Ye Lin

C/Camino de Vera SN

Universidad Politècnica de València

Departamento de Ingeniería Electrónica, Ed. 7F

46022, València

València

Ext. 76026 

 

 

 

De: fieldtrip <fieldtrip-bounces at science.ru.nl> En nombre de Schoffelen, J.M. (Jan Mathijs) via fieldtrip
Enviado el: jueves, 6 de octubre de 2022 8:09
Para: FieldTrip discussion list <fieldtrip at science.ru.nl>
CC: Schoffelen, J.M. (Jan Mathijs) <janmathijs.schoffelen at donders.ru.nl>
Asunto: Re: [FieldTrip] sloreta doest not get unity source variance

 

Hi Yiyao, 

 

To be honest, I don’t understand your question. And it is not clear what the problem is. 

 

Can you please have a look at the documentation below and reformulate your question, so that the readership of the list can constructively think along?

 

https://www.fieldtriptoolbox.org/faq/how_to_ask_good_questions_to_the_community/

 

https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1002202

 

http://www.catb.org/esr/faqs/smart-questions.html

 

Best wishes,

Jan-Mathijs

 

 





On 5 Oct 2022, at 18:49, Yiyao Ye Lin via fieldtrip <fieldtrip at science.ru.nl <mailto:fieldtrip at science.ru.nl> > wrote:

 

 

Dear researchers,

 

After reading the sLoreta theory, I attempted to understand the sloreta implementation detail. I attempted to obtain the source covariance matrix, and I could not get the expected unit variance. To do this, I attempted to calculate by two ways:

a)       lf'*invG*lf after line 268 of ft_inverse_sloreta

b)      lf(:,ii)'*invG*lf(:,ii) at line 267 of ft_inverse_sloreta

For this, I used EEG signal with average reference. 

What's wrong? How can the unity variance of source variance matrix? 

 

Best regards

*******************

Yiyao Ye Lin

C/Camino de Vera SN

Universidad Politècnica de València

Departamento de Ingeniería Electrónica, Ed. 7F

46022, València

València

Ext. 76026 

 

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 <https://doi.org/10.1371/journal.pcbi.1002202> https://doi.org/10.1371/journal.pcbi.1002202

 

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